Abstract P2-13-03: Complications following total skin-sparing mastectomy and expander-implant reconstruction: Effects of radiation therapy on the stages of reconstruction

BACKGROUND

With increasing numbers of patients requiring post-mastectomy radiation therapy (PMRT), many patients undergoing total-skin sparing mastectomy (TSSM) and immediate two-staged expander-implant (TE-I) reconstruction will receive radiation therapy (XRT) during the course of their reconstruction. Additionally, many patients undergoing TSSM for recurrent cancer have a history of prior lumpectomy and XRT. While the increased risk of reconstructive complications in the setting of XRT has been well-documented, few studies have looked at the impact of XRT on the stages of TE-I reconstruction.

METHODS

All patients undergoing TSSM and immediate two-staged TE-I reconstruction between 2006 and 2013 were identified from a prospectively maintained database. The incidences of TE-I loss and severe infection requiring admission for IV antibiotics were assessed in the subsets of patients with a prior history of XRT and those who received PMRT. Complications were divided into those following the first stage of reconstruction (TSSM and TE placement) and those following the second stage (TE-I exchange).

RESULTS

A total of 218 TSSM and TE-I reconstruction cases were included in the analysis, 85 (39%) with prior XRT and 133 (61%) with PMRT, all of whom who received PMRT prior to TE-I exchange. Mean follow-up time was 2.5 years. Nearly all cases of prior XRT occurred in patients who developed a local recurrence and then underwent TSSM; mean time from prior XRT to TSSM was 7 years (range: 2 months to 22 years). Patients with prior XRT were much more likely to develop complications following the first stage of reconstruction than after the second stage (TE-I loss: 15% vs. 4%, p = 0.02; infection: 20% vs. 8%, p = 0.02). Patients who received PMRT had low rates of complications following the first stage of reconstruction, when they had not yet received any radiation exposure (TE-I loss: 3%; infection: 8%). However, rates increased significantly following TE-I exchange, with an 18% TE-I loss and 30% rate of infection, which was nearly 4-fold higher than patients with a prior history of XRT.

CONCLUSIONS

Patients with prior XRT are at significantly increased risk of reconstructive complications following the first stage of TE-I reconstruction after TSSM, even with a remote history of XRT. However, if these patients are able to successfully maintain their reconstruction through tissue expansion, their risk of complications at the second stage is comparable to patients without radiation exposure and significantly lower than patients receiving PMRT. Careful patient selection and appropriate pre-operative counseling for TSSM and TE-I reconstruction is critical to optimize outcomes and set appropriate expectations.

Citation Format: Sears M, Warren Peled A, Wang F, Foster RD, Alvarado M, Wong J, Ewing CA, Esserman LJ, Sbitany H, Fowble B. Complications following total skin-sparing mastectomy and expander-implant reconstruction: Effects of radiation therapy on the stages of reconstruction. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-13-03.

Abstract P2-13-01: An innovative risk-reducing approach to post-mastectomy radiation delivery following autologous breast reconstruction

Introduction:

There is no consensus among radiation oncologists regarding delivery of post-mastectomy radiation therapy (PMRT) after immediate autologous breast reconstruction, and plastic surgeons rarely participate in this decision-making process. However, radiation-induced changes markedly influence flap outcomes and affect the flap permanently. We present an innovative approach for PMRT delivery, through the use of custom bolus. This technique provides individualized, targeted PMRT to the reconstructed breast to minimize flap-related complications.

Methods:

All patients who underwent mastectomy with immediate autologous reconstruction between 2005 and 2014 at our institution were identified. Radiation was delivered to the reconstructed autologous breast in 29 patients. Post-irradiation complications and reconstruction outcomes were compared for patients treated with custom bolus, standard PMRT, and historical controls.

Results:

Over the past 10 years, 157 patients (226 breasts) underwent immediate autologous tissue breast reconstruction following mastectomy. Of the 29 patients who received PMRT, 10 were treated with custom bolus. The custom bolus uses perforated Aquaplast and a nearly tissue-equivalent wax to form a cast which conforms to the irregular contours of the chest wall, allowing for easy application through the duration of treatment. Pre-irradiation computed tomography was used to optimize dose distribution, evaluate the internal mammary vessels, and target the deeper tissues adjacent to the chest wall (minimizing dose inhomogeneity to the skin). Custom bolus resulted in fewer radiation-induced skin changes and less skin tethering/fibrosis than standard bolus (0% vs 10% and 20% vs 35%, respectively), and less volume loss and contour deformities compared with historical controls (10% vs 22.8% and 10% vs 30.7%, respectively).

Conclusion:

The use of custom bolus tailors radiation delivery to the internal mammary vessels, anastomoses, and skin; uniformly doses the surgical incision; and provides the necessary radiation dose to prevent recurrence, thus not compromising oncologic safety. It is easily fabricated, cost-effective and placement is straightforward and reproducible. Because radiation has negative effects on autologous breast reconstruction and often results in vascular intimal fibrosis and fat necrosis, plastic surgeons should participate in radiation planning. Our custom bolus PMRT technique reduces the incidence of these radiation effects.

Citation Format: Piper ML, Evangelista M, Amara D, Daar DA, Foster RD, Fowble B, Sbitany H. An innovative risk-reducing approach to post-mastectomy radiation delivery following autologous breast reconstruction. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-13-01.

Abstract CS01-2: The role of radiation in the treatment of the axilla in the setting of neoadjuvant chemotherapy

There is considerable controversy regarding the appropriate surgical procedure and its timing for evaluating the status of the axillary nodes in the neoadjuvant setting. Sentinel lymph node (SLN) surgery following initial chemotherapy avoids an axillary dissection and its associated morbidity in clinical N0 patients who have pathologic negative SLN. SLN identification and false negative rates (FNR) have been acceptable in these women and axillary recurrence rates without radiation directed to the axilla are £1%. For clinical N1 disease, 2 recent studies (SENTINA, ACOSOG 1071) reported SLN identification rates of 80% and 91%, FNR of 12.8 and 14% and ypN0 rates of 52% and 40% respectively. The SLN was the only positive node(s) in 58% and 40% of the ypN1 patients. Several studies have evaluated the role of regional node (RN) irradiation in clinical N1 patients who are ypN0 following neoadjuvant chemotherapy and have found no improvement in local-regional disease free survival. RN failure rates are low as reported by the NSABP B18 and 27 trials in the absence of post mastectomy radiation or with breast only radiation. The question of RN radiation is being addressed by an NRG (NSABP-RTOG) randomized trial. For women with clinical N1 disease who remain ypN1, axillary radiation may substitute for axillary dissection. Axillary radiation has been shown in randomized trials to be equivalent to axillary dissection in the adjuvant setting for clinical N0 women (NSABP B04) including those with positive SLN (Dutch Mirror, IBCSG 23-01, AMAROS). The Alliance trial will address this question. The potential advantage of neoadjuvant chemotherapy is the ability to adjust surgical and radiation treatment based on pathologic response and thereby minimize the morbidity of combined therapy. Various clinical scenarios will be presented with treatment options.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr CS01-2.

Abstract P4-01-13: Practice patterns of MRI utilization for breast cancer treatment within the University of California system as part of the Athena initiative

Background: The appropriate utilization of Breast MRI in breast cancer care remains controversial. As part of a quality improvement initiative for breast cancer screening and treatment, we sent out a survey to physicians who treat breast cancer patients. All respondents are participants in the ATHENA initiative, a program which unites physicians, researchers, and patients at the five University of California medical centers.

Objective: To use the ATHENA infrastructure to perform a qualitative analysis of variations in breast cancer care.

Methods: Surveys were sent to 50 physicians in the ATHENA network whose practices are focused on breast cancer. Respondents were presented with clinical scenarios, and asked whether they would recommend MRI always/usually or sometimes/never. Differences were compared by Chi square.

Results: 39 physicians completed the survey (78% response rate). Of these physicians 29% were surgeons, 26% radiation oncologists and 45% medical oncologists. Athena physicians were more likely to order MRI for high risk screening of mutation carriers than not (85% yes vs. 15% no, p < 0.003) but not based on breast density alone or previous history of breast cancer. They were also more likely to order it for monitoring neo-adjuvant chemotherapy (70% yes vs. 30% no, p < 0.03). Although the majority answered that they would order a Breast MRI for new breast cancer the difference between responses was not significantly different (56% yes vs. 44%, p = 0.07).

Conclusion: Athena physicians follow established published guidelines which demonstrate a benefit for Breast MRI screening for BRCA mutation carriers but not based on density or previous history of breast cancer. The Athena network allows a forum for new practice guidelines to be implemented as data becomes available to improve patient outcomes and utilize the best evidence for patient care, where both the patterns of MRI use as well as the outcomes of practice patterns will be evaluated prospectively.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-01-13.

Abstract P4-16-07: Selective use of post-mastectomy radiation therapy in the neoadjuvant setting

Background: Neoadjuvant chemotherapy, once reserved for locally advanced breast cancer, has become more common in Stage II disease. While one of its proven benefits is an increase in the frequency of breast conserving surgery, many women will undergo mastectomy despite an excellent clinical response. Indications for post-mastectomy radiation (PMRT) following neoadjuvant therapy are not well defined. Some studies have suggested that certain subgroups of women (young age, triple negative disease) with negative nodes or 1–3 positive nodes after chemotherapy have a significant risk of local-regional failure without PMRT. We conducted a single-institution retrospective study of women undergoing neoadjuvant chemotherapy and mastectomy without PMRT to assess clinical outcomes among this cohort.

Methods: 101 women with initial stage I-III disease (20% stage I, 72% stage II, 8% stage III) received neoadjuvant chemotherapy (doxorubicin-based +/− taxane) followed by mastectomy without PMRT between 2005 and 2011. Mean age was 49 years (range 22–81 years). 16% were BRCA+. 66 patients (65%) had clinically negative axillary nodes at presentation, 34% had N1 disease and 1% had N2 disease. Subtype by IHC was 61% luminal A, 11% luminal B (ER+, Her2+), 20% triple negative and 8% ER−, Her2+. At the time of surgery, 81% were node negative and 19% had 1–3 positive nodes. Pathologic complete response (pCR) (breast + axilla) occurred in 28%. Median follow-up was 34 months (range 5.5–84.5 months).

Results: There were 2 (2%) local-regional failures (1 axillary recurrence at 52 months after mastectomy and 1 chest wall recurrence at 10 months). Both of these recurrences were in patients with negative nodes and luminal A tumors; patients had 2.2 and 2.5 cm of residual invasive cancer, respectively, and negative margins at mastectomy. There were no local-regional failures in women with triple negative cancers, those with 1–3 positive nodes, or patients younger than 40. Additionally, there were no failures in women with a pCR, including those with initial stage IIIA-B disease.

Conclusions: Among carefully selected patients fulfilling low risk criteria for local-regional recurrence, PMRT following neoadjuvant chemotherapy may be omitted without compromising local-regional control.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-16-07.

Evidence-based indications for post-mastectomy radiation after neoadjuvant chemotherapy for stage II-III breast cancer

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Background: There are no established guidelines to define the role of post-mastectomy radiation therapy after neoadjuvant chemotherapy. We sought to identify a cohort of women with stage II-III breast cancer in whom radiation may be omitted based on the risk of local-regional failure (LRF).

Methods: Seven breast cancer physicians participating in the multi-campus University of California (UC) Athena Breast Health Network identified, reviewed and abstracted the available literature (from MEDLINE and Cochrane databases), formulated evidence tables (endpoints LRF, disease-free, and overall survival) and developed a risk assessment table of women undergoing mastectomy after neoadjuvant chemotherapy. We created 18 hypothetical clinical case scenarios, and using the American College of Radiology appropriateness criteria methodology, assigned appropriateness ratings for post-mastectomy radiation for each scenario based on our literature review.

Results: 23 of 24 studies identified were retrospective from single institutions. Consensus (80% agreement in a category) in the appropriateness rating was achieved for 78% of the clinical scenarios. Distinct LRF risk categories emerged. Patients who presented with clinical stage II (T1-2N0-1) ER(+) disease with age at diagnosis ≥35-40 years who had either a pathologic complete response (pCR) or 0-3 positive nodes without LVI or ECE were identified as having ≤10% risk of LRF without radiation. Limited data support pCR stage IIIA patients as being low risk.

Conclusions: In the absence of randomized trial data, we identified existing data to guide the use of PMRT in the neoadjuvant chemotherapy setting. Using this data and the appropriateness ratings, we found a high concordance of treatment recommendations for PMRT in our clinical scenarios and were able to identify a cohort of women with a low risk of LRF without radiation. These women will form the basis for future clinical studies in the UC Athena Breast Health Network.

Abstract PD06-02: Are Outcomes Really Similar after Lumpectomy and Mastectomy for Early Stage Invasive Breast Cancer? Evidence from Population-Based Data

Background: Randomized clinical trials have established equivalent survival for patients undergoing breast conserving therapy and radiation (BCT) compared to those undergoing mastectomy (M). However, these studies were conducted over two decades ago prior to the era of widespread systemic therapy and improved locoregional therapy and did not assess separately effects by age and tumor type types. We examined survival in a contemporary and representative series of women undergoing BCT or M without radiation for early stage (I-II) breast cancer to assess observationally whether survival varied by surgical treatment among age groups and tumor types.

Methods: We used the population-based California Cancer Registry supported by the NCI's Surveillance, Epidemiology and End Results (SEER) Program. We included women diagnosed with stage I and II breast cancer between 1990 and 2003, treated with either BCT or M, and followed for vital status for through the end of 2008. Overall survival (OS) and disease-specific survival (DSS) were compared between BCT and M groups using the Cox proportional hazards model, adjusting for tumor stage at diagnosis, tumor size, grade, number of positive nodes and race. Analysis was stratified by age group (<50 years and ≥50 years) and tumor estrogen receptor (ER) status.

Results: 139,430 women fulfilling eligibility criteria and 15,917deaths were identified in the cohort between 1990 and 2003; overall 5-year survival was 93.7% (95% CI 93.6-93.9%). 26% of the total cohort were <50 years of age at diagnosis; 62% were ER-positive. Stage at diagnosis, tumor size, grade, number of positive nodes and race differed significantly among the BCT and M groups. Adjusting for all of these factors, women undergoing BCT had a significantly lower hazard of mortality when compared to women who had M (hazard ratio (HR) 0.84, 95% confidence interval (CI) 0.79 - 0.89), with a more pronounced survival difference among women >50 (HR 0.76, 95% CI 0.73 — 0.79). This effect did not differ by ER status among women aged <50. However, among women aged ≥50, this effect was significantly stronger among ER(+) (HR 0.76, 95% CI 0.71-0.80) than ER(-) tumors (HR 0.81, 95% CI 0.75-0.89).

Conclusion: In a large, representative series of patients with early stage breast cancer, irrespective of age group or ER status, BCT was independently associated with a significant 19-32% improvement in OS. Although it is highly likely that at least some of this difference relates to unmeasured tumor characteristics or baseline health characteristics influencing treatment choice or overall survival, these findings are provocative and should be further explored in data resources with greater clinical detail.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD06-02.

Abstract P5-14-02: Immediate Breast Reconstruction: The Effect of Radiation

Background:

Prior history of breast irradiation or anticipated need for postmastectomy radiation have been considered relative contraindications for immediate breast reconstruction. We evaluated the surgical outcomes between three groups of patients: patients without radiation exposure, those with radiation prior to immediate reconstruction, and those with radiation following immediate reconstruction to determine the differences in risk of post-surgical complications among groups. Methods:

All patients undergoing mastectomy and immediate reconstruction with either a tissue expander or implant between January 1, 2005 and June 30, 2009 were entered into an IRB-approved prospective database. Routine institutional protocol consisted of immediate reconstruction with tissue expander, expansion during the1-2 months following surgery, radiation if indicated, followed by implant exchange at 3-6 months after completion of radiation. All complications were collected and recorded within a week of the event, and all patients had a minimum follow-up period of 6 months after implant exchange to allow for sufficient monitoring of complications. Major complications included infection requiring IV antibiotics, unplanned return to surgery, and tissue expander/implant loss. Results:

A total of 446 mastectomies were identified. Of these, 341 had no radiation history, 33 had prior ipsilateral breast radiation, and 72 had post-mastectomy radiation. Overall, there were 160 major complications (36%), including 50 (11%) expander/implant losses. Patient age, BMI, diabetes, and history of tobacco use were not associated with increased risk of major complications in this cohort. However, both prior and postoperative radiation was associated with higher risk of both major complications and implant loss.

Conclusion:

Immediate reconstruction with implant or tissue expander is associated with a 36% risk of major postoperative complications, with the greatest number seen in those patients with history of previous chest wall irradiation. However, most implants were salvaged even in the setting of complications, and the overall implant loss rate was only 8% in unirradiated patients and 22% in those patients with postoperative RT. Although radiation history is not a contraindication to immediate breast reconstruction, patients undergoing this procedure must be well informed of their substantial risk of postoperative complications.

Low complication rates are achievable after postmastectomy breast reconstruction and radiation therapy

PURPOSE

To report our institution's experience of complications and cosmetic results among patients who underwent modified radical mastectomy followed by reconstruction and radiation therapy (RT).

METHODS AND MATERIALS

Between 1987 and 2002, 85 patients with breast cancer underwent modified radical mastectomy, breast reconstruction, and postoperative RT. Reconstruction consisted of tissue expander/implant (TE/I) in 50 patients and an autologous transverse rectus abdominis myocutaneous (TRAM) flap in 35 patients. The primary end point of this study was the actuarial incidence of major and minor complications involving the reconstruction. Cosmesis was also assessed at each follow-up visit.

RESULTS

The median follow-up from reconstruction was 28 months. The 5-year major complication rate was 0% in the TRAM group vs. 5% in the TE/I group (p = 0.21). The 5-year minor complication rate was 39% for the TRAM group vs. 14% for the TE/I group (p = 0.04). None (0%) of the TRAM complications required any corrective surgery, whereas 2 (33%) of the TE/I complications required implant removal. Of the TRAM patients with complications, 100% had superior cosmetic scores of excellent/good compared to only 17% of the TE/I patients who had complications (p = 0.003). Use of our custom-fashioned bolus resulted in a lower complication rate compared with standard bolus (p = 0.05).

CONCLUSIONS

Patients treated with breast reconstruction and RT can experience a very low rate of major complications. We demonstrate no significant difference in the overall rate of major complications between TRAM and TE/I patients. Bolus can be safely used during postmastectomy RT with reconstruction, and we advocate the use of a custom wax bolus in the treatment of these patients. Postmastectomy RT should be considered in all eligible patients, even in the setting of reconstruction.

Recursive partitioning identifies patients at high and low risk for ipsilateral tumor recurrence after breast-conserving surgery and radiation

PURPOSE

Recursive partitioning analysis (RPA), a method of building decision trees of significant prognostic factors for outcome, was used to determine subgroups at significantly different risk for ipsilateral breast tumor recurrence (IBTR) in early-stage breast cancer.

PATIENTS AND METHODS

Nine hundred twelve women underwent breast-conserving surgery, axillary dissection, and radiation. Systemic therapy was chemotherapy with or without tamoxifen in 32%, tamoxifen in 27%, or none in 41%. RPA was used to create a decision tree according to predictive variables that classify patients by IBTR risk, and the Kaplan-Meier method was used to calculate 10-year risks. Median follow-up was 5.9 years.

RESULTS

Age was the first split in the partition tree. Patients more than 55 years old had a 4% 10-year IBTR, the only further division being use of tamoxifen or not (2% v 5%, P =.03). For patients </= 55 years old, extensive intraductal component (EIC) was the next significant split. For EIC-negative tumors, age </= 35 years and negative margins were associated with a 10-year IBTR of 3%; with close (</= 2 mm) or positive margins, 34%. Patients 36 to 55 years old with estrogen receptor-positive tumors receiving tamoxifen had a risk of IBTR of 5%, but had a 20% risk without tamoxifen.

CONCLUSION

This RPA showed that age </= 55 versus more than 55 years was the most significant factor for IBTR. Patients </= 35 years old had a low risk of IBTR when tumors were EIC-negative with negative margins. EIC was an independent factor for IBTR for ages </= 55 years. Use of tamoxifen was the most significant factor for patients older than 55 years, but it resulted in a greater absolute decrease in risk of IBTR for patients 36 to 55 years old.

Quantifying radiation therapy-induced brain injury with whole-brain proton MR spectroscopy: initial observations

PURPOSE

To quantify the extent of neuronal cell loss imparted to the brain by means of radiation therapy through the decline of the amino acid derivative N-acetylaspartate (NAA) by using proton (hydrogen 1) magnetic resonance (MR) spectroscopy.

MATERIALS AND METHODS

Proton MR spectroscopy in a clinical MR imager was used to ascertain the amount of whole-brain NAA before and immediately after whole-brain radiation therapy 3-4 weeks later. Eight patients (four women, four men; median age, 55 years; age range, 39-70 years) were studied. All subjects had lung cancer (non-small cell lung cancer [n = 5], small-cell lung cancer [n = 3]) and received either palliative or prophylactic whole-brain radiation therapy. Six of them also underwent a Mini-Mental Status Examination (MMSE) for correlation with the whole-brain NAA. Two-tailed Student t tests were used to evaluate the data.

RESULTS

A significant (P = .042) average decline in whole-brain NAA of -0.91 mmol per person was observed in the cohort. No corresponding changes occurred in MMSE scores. There was no significant difference in whole-brain NAA decline between prophylactic and therapeutic whole-brain radiation therapy.

CONCLUSION

Since whole-brain NAA loss was detected even when MMSE scores were unchanged, the former seems to be a more sensitive measure of radiation therapy injury than is the latter.

Second cancers after conservative surgery and radiation for stages I-II breast cancer: identifying a subset of women at increased risk

PURPOSE

To assess the risk and patterns of second malignancy in a group of women treated with conservative surgery and radiation in a relatively contemporary manner for early-stage invasive breast cancer, and to identify a subgroup of these women at increased risk for a second cancer.

METHODS AND MATERIALS

From 1978 to 1994, 1,253 women with unilateral Stage I-II breast cancer underwent wide excision, axillary dissection, and radiation. The median follow-up was 8.9 years, with 446 patients followed for >or= 10 years. The median age was 55 years. Sixty-eight percent had T1 tumors and 74% were axillary-node negative. Radiation was directed to the breast only in 78%. Adjuvant therapy consisted of chemotherapy in 19%, tamoxifen in 19%, and both in 8%. Factors analyzed for their association with the cumulative incidence of all second malignancies, contralateral breast cancer, and non-breast cancer malignancy were: age, menopausal status, race, family history, obesity, smoking, tumor size, location, histology, pathologic nodal status, region(s) treated with radiation, and the use and type of adjuvant therapy.

RESULTS

One hundred seventy-six women developed a second malignancy (87 contralateral breast cancers at a median interval of 5.8 years, and 98 non-breast cancer malignancies at a median interval of 7.2 years). Nine women had both a contralateral breast cancer and non-breast cancer second malignancy. The 5- and 10-year cumulative incidences of a second malignancy were 5% and 16% for all cancers, 3% and 7% for contralateral breast cancer, 3% and 8%, for all second non-breast cancer malignancies, and 1% and 5%, respectively, for second non-breast cancer malignancies, excluding skin cancers. Patient age was a significant factor for contralateral breast cancer and non-breast cancer second malignancy. Young age was associated with an increased risk of contralateral breast cancer, while older age was associated with an increased the risk of a second non-breast cancer second malignancy. A positive family history increased the risk of contralateral breast cancer, but not non-breast cancer malignancies. The risk of a contralateral breast cancer increased as the number of affected relatives increased. Tamoxifen resulted in a nonsignificant decrease in contralateral breast cancer and an increase in non-breast cancer second malignancies. The 5-and 10-year cumulative incidences for leukemia and lung cancer were 0.08% and 0.2%, and 0.8% and 1%, respectively. There was no significant effect of chemotherapy or the regions treated with radiation on contralateral breast cancer or non-breast cancer second malignancy. The most common types of second non-breast cancer malignancies were skin cancers, followed by gynecologic malignancies (endometrial), and gastrointestinal malignancies (colorectal and pancreas).

CONCLUSION

The 10-years cumulative incidence of a second cancer in this study was 16%. Young age and family history predicted for an increased risk of contralateral breast cancer, and older age predicted for an increased risk of non-breast cancer malignancy. The majority of patients treated with conservative surgery and radiation with or without adjuvant systemic therapy will not develop a second cancer. Long-term follow-up is important to document the risk and patterns of second cancer, and knowledge of this risk and the patterns will influence surveillance and prevention strategies.

Lobular carcinoma in situ increases the risk of local recurrence in selected patients with stages I and II breast carcinoma treated with conservative surgery and radiation

BACKGROUND

Lobular carcinoma in situ (LCIS) is a known risk factor for the development of invasive breast carcinoma. However, little is known regarding the impact of LCIS in association with an invasive carcinoma on the risk of an ipsilateral breast tumor recurrence (IBTR) in patients who are treated with conservative surgery (CS) and radiation therapy (RT). The purpose of this study was to examine the influence of LCIS on the local recurrence rate in patients with early stage breast carcinoma after breast-conserving therapy.

METHODS

Between 1979 and 1995, 1274 patients with Stage I or Stage II invasive breast carcinoma were treated with CS and RT. The median follow-up time was 6.3 years.

RESULTS

LCIS was present in 65 of 1274 patients (5%) in the study population. LCIS was more likely to be associated with an invasive lobular carcinoma (30 of 59 patients; 51%) than with invasive ductal carcinoma (26 of 1125 patients; 2%). Ipsilateral breast tumor recurrence (IBTR) occurred in 57 of 1209 patients (5%) without LCIS compared with 10 of 65 patients (15%) with LCIS (P = 0.001). The 10-year cumulative incidence rate of IBTR was 6% in women without LCIS compared with 29% in women with LCIS (P = 0.0003). In both groups, the majority of recurrences were invasive. The 10-year cumulative incidence rate of IBTR in patients who received tamoxifen was 8% when LCIS was present compared with 6% when LCIS was absent (P = 0.46). Subsets of patients in which the presence of LCIS was associated with an increased risk of breast recurrence included tumor size < 2 cm (T1), age < 50 years, invasive ductal carcinoma, negative lymph node status, and the absence of any adjuvant systemic treatment (chemotherapy or hormonal therapy) (P < 0.001). LCIS margin status, invasive lobular carcinoma histology, T2 tumor size, and positive axillary lymph nodes were not associated with an increased risk of breast recurrence in these women.

CONCLUSIONS

The authors conclude that the presence of LCIS significantly increases the risk of an ipsilateral breast tumor recurrence in certain subsets of patients who are treated with breast-conserving therapy. The risk of local recurrence appears to be modified by the use of tamoxifen. Further studies are needed to address this issue.

Local recurrence of breast cancer in the stereotactic core needle biopsy site: case reports and review of the literature

Early mammographic detection of nonpalpable breast lesions has led to the increasing use of stereotactic core biopsies for tissue diagnosis. Tumor seeding the needle tract is a theorectical concern; the incidence and clinical significance of this potential complication are unknown. We report three cases of subcutaneous breast cancer recurrence at the stereotactic biopsy site after definitive treatment of the primary breast tumor. Two cases were clinically evident and relevant; the third was detected in the preclinical, microscopic state. All three patients underwent multiple passes during stereotactic large-core biopsies (14 gauge needle) followed by modified radical mastectomy. Two patients developed a subcutaneous recurrence at the site of the previous biopsy 12 and 17 months later; one had excision of the skin and dermis at the time of mastectomy revealing tumor cells locally. In summary, clinically relevant recurrence from tumor cells seeding the needle tract is reported in two patients after definitive surgical therapy (without adjuvant radiation therapy). Often, the biopsy site is outside the boundaries of surgical resection. Since the core needle biopsy exit site represents a potential area of malignant seeding and subsequent tumor recurrence, we recommend excising the stereotactic core biopsy tract at the time of definitive surgical resection of the primary tumor.

Local recurrence after mastectomy or breast-conserving surgery and radiation

Approximately 10% to 15% of patients with stage I/II invasive breast cancer will develop a clinically isolated local recurrence. The standard management of an ipsilateral breast tumor recurrence following breast-conserving surgery and radiation is salvage mastectomy, while local excision and radiation are optimal treatment of a chest wall recurrence following initial mastectomy. Although there are few data regarding the efficacy of systemic therapy after isolated local relapse, chemotherapy and/or hormonal therapy should be considered for most patients because of the high risk of subsequent distant relapse. However, local relapse does not always herald distant metastases. A prolonged interval between initial treatment and local recurrence is the most important prognostic factor for subsequent outcome, and when combined with other favorable characteristics, can predict 5-year survival rates of 70% or higher.

Accuracy of the extent of axillary nodal positivity related to primary tumor size, number of involved nodes, and number of nodes examined

PURPOSE

While a number of studies have evaluated the minimum number of axillary nodes that need to be examined to accurately determine nodal positivity or negativity, there is little information on the number of nodes which must be examined to determine the extent of nodal positivity. This study attempts to determine for patients with 1-3 positive nodes the probability that the number of positive nodes reported is the true number of positive nodes as well as the probability that 4 or more nodes could be positive based on primary tumor size and number of nodes examined.

MATERIALS AND METHODS

From 1979 to 1998, 1652 women with Stages I-II invasive breast cancer underwent an axillary dissection as part of their breast conservation therapy and had more than 10 lymph nodes examined. The mean and median number of nodes identified in the dissection was 19 and 17 (range, 11-75). The median age was 55 years. A total of 1155 women had T1 tumors and 497 had T2 tumors. Of the 459 node-positive women, 72% had 1-3 positive nodes, 18% had 4-9 positive nodes, and 10% had 10 or more positive nodes. A mathematical model based on tumor size and number of nodes examined was created using the hypergeometric distribution and Bayes Theorem. The resulting model was used to estimate the accuracy of the reported number of positive nodes and the probability of 4 or more positive nodes based on various observed sampling combinations.

RESULTS

For patients with T1 tumors and 1, 2, or 3 positive nodes, the minimum number of nodes examined needed for a 90% probability of accuracy is 19, 20, and 20. For T2 tumors and 1, 2, or 3 positive nodes, a minimum of 20 nodes is required. The probability of 4 or more positive nodes increases as tumor size and the number of reported positive nodes increase and as the number of examined nodes decreases. For a 10% or less probability of 4 or more positive nodes, a patient with a T1 tumor and 1, 2, or 3 observed positive nodes would require a minimum of 8, 15, and 20 nodes removed. For a T2 tumor and 1, 2, or 3 observed positive nodes, the corresponding numbers are 10, 16, and 20.

CONCLUSION

The accuracy of the extent of axillary nodal positivity is influenced by the number of observed positive nodes, tumor size, and the number of nodes examined. Underestimation of the number of positive nodes will result in errors in the assessment of an individual's risk for locoregional recurrence, distant disease, and breast cancer death and will adversely impact on treatment recommendations. This model provides the clinician with a means for assessing the accuracy of the number of positive nodes reported in patients with 1-3 positive nodes.

Internal mammary node irradiation neither decreases distant metastases nor improves survival in stage I and II breast cancer

PURPOSE

To compare outcome for ipsilateral breast tumor recurrence (IBTR), or regional node recurrence, initial and subsequent distant metastases, and overall and cause-specific survival in women treated with conservative surgery and radiation based on whether or not radiation was targeted to the internal mammary nodes (IMN).

METHODS AND MATERIALS

From 1979-1994, 1383 women with Stage I-II breast cancer underwent wide excision, axillary node dissection with >/=10 nodes removed, and radiation. Median follow-up was 6 years; median age was 55 years. A total of 114 women had radiation targeted to the IMN with deep tangents and 1269 did not. Women who received IMN treatment were more often axillary node-positive (40% vs. 25%, p = 0. 002), had central or inner quadrant tumors (61% vs. 40%, p = 0.001), and had T2 tumors (47% vs. 31%, p = 0.001). All axillary node-positive women received adjuvant chemotherapy and/or tamoxifen. For axillary node-negative women, 13% of the IMN treatment group received adjuvant systemic therapy compared to 37% of the no treatment group (p = 0.001). Radiation was directed to the breast only in 97% of the axillary node-negative women who had IMN treatment and 99% of the no IMN treatment group. For axillary node-positive women, 98% of the IMN-treated group had radiation to the breast and supraclavicular nodes +/- a posterior axillary field compared to 77% of the no IMN treatment group (p = 0.001). There were no significant differences between the two groups for median age, menopausal status, histology, final surgical margin, estrogen and progesterone receptor status, or the number of positive nodes.

RESULTS

There were no significant differences in the 5- and 10-year cumulative incidence of an IBTR, regional node recurrence, initial or total distant metastases for the two groups. Similarly 5- and 10-year actuarial overall and cause-specific survival were not significantly different. However, subset analysis revealed a statistically significant increase in initial (29% vs. 15% at 10 yr, p = 0.002) and total (30% vs. 17% at 10 yr, p = 0.01) distant metastases and a significant decrease in cause-specific survival (76% vs. 89% at 10 yr, p = 0.02) for postmenopausal women who received IMN treatment. These findings could not be attributed to differences in the use of systemic therapy or the number of positive nodes. Axillary node-positive patients did not experience a significant decrease in initial (36% vs. 22% at 10 yr, p = 0.21) or total distant metastases (37% vs. 28% at 10 yr, p = 0.62) or a significant improvement in cause-specific survival (72% vs. 76% at 10 yr, p = 0.76) with IMN treatment regardless of whether the tumor was lateral or medial/central in location. IMN treatment was not associated with an increase in non-breast cancer deaths during this period of observation.

CONCLUSIONS

This retrospective series was unable to identify a significant benefit for IMN irradiation in terms of distant metastases or cause-specific survival for the entire patient population, and in particular, for patients with positive axillary nodes and medially located lesions. The results of the proposed or ongoing prospective randomized trials will further address this controversial issue.

Microinvasive breast carcinoma: clinicopathologic analysis of a single institution experience

BACKGROUND

Microinvasive breast carcinoma (MIC) has a good prognosis but specific definitions have varied in the past, making the clinical significance of MIC a subject of debate.

METHODS

Microscopic slides of 59 cases of breast carcinoma originally diagnosed as MIC were reviewed retrospectively. Histologic parameters were correlated with clinical findings and outcome to define diagnostic criteria better.

RESULTS

On review, the 59 cases were recategorized as follows: pure DCIS (N = 16), DCIS with foci equivocal for microinvasion (N = 7), DCIS with > or =1 focus of microinvasion (N = 11), T1 invasive carcinomas with > or =90% DCIS (N = 18), and T1 tumors with <90% DCIS (N = 7). The MIC cases in the current study averaged 3 separate foci of early infiltration outside the basement membrane, each one not >1.0 mm. The mean follow-up was 95 months. Six patients (10%) had only local recurrence: 1 case each in patients with equivocal microinvasion, microinvasion, and T1 tumors with <90% DCIS and 3 cases among the patients with T1 tumors with > or = 90% DCIS. Four patients, all with T1 tumors with > or =90% DCIS, had distant failure (7%). In the MIC group, only one patient developed a local recurrence after breast conservation. No patient had axillary lymph node metastasis. For the entire series, factors associated with local recurrence were younger age, breast conservation versus mastectomy, and close surgical margins. The only factor associated with distant failure was the size of the DCIS component. Seven patients with T1 tumors with > or =90% DCIS experienced local or distant failure and 5 of these (71%) developed progressive disease or died of disease. All other patients who developed a recurrence were disease free at last follow-up. In a retrospective series, poorer outcome in carcinomas with > or =90% DCIS may be related to the greater likelihood of missed larger areas of invasive carcinoma. Therefore, meticulous and extensive sampling of these carcinomas is required.

CONCLUSIONS

MIC as defined has a good prognosis. It has a different biology than T1 invasive carcinoma with > or =90% DCIS, which may progress and cause death. Large tumors with multiple foci of microinvasion may have metastatic potential.

Should internal mammary lymph nodes in breast cancer be a target for the radiation oncologist?

PURPOSE

The elective treatment of internal mammary lymph nodes (++IMNs) in breast cancer is controversial. Previous randomized trials have not shown a benefit to the extended radical mastectomy or elective IMN irradiation overall, but a survival benefit has been suggested by some for subgroups of patients with medial tumors and positive axillary lymph nodes. The advent of effective systemic chemotherapy and potential for serious cardiac morbidity have also been factors leading to the decreased use of IMN irradiation during the past decade. The recent publishing of positive trials testing postmastectomy radiation that had included regional IMN irradiation has renewed interest in their elective treatment. The purpose of this study is to critically review historical and new data regarding IMNs in breast cancer.

METHODS AND MATERIALS

The historical incidence of occult IMN positivity in operable breast cancer is reviewed, and the new information provided by sentinel lymph node studies also discussed. The results of published randomized prospective trials testing the value of elective IMN dissection and/or radiation are analyzed. The data regarding patterns of failure following elective IMN treatment is studied to determine its impact on local-regional control, distant metastases, and survival. A conclusion is drawn regarding the merits of elective IMN treatment based on this review of the literature.

RESULTS

Although controversial, the existing data from prospective, randomized trials of IMN treatment do not seem to support their elective dissection or irradiation. While it has not been shown to contribute to a survival benefit, the IMN irradiation increases the risk of cardiac toxicity that has effaced the value of radiation of the chest wall in reducing breast cancer deaths in previous randomized studies and meta-analyses. Sentinel lymph node mapping provides an opportunity to further evaluate the IMN chain in early stage breast cancer. Biopsy of "hot" nodes may be considered in the future to select patients who are most likely to benefit from additional regional therapy to these nodes.

CONCLUSIONS

Irradiation of the IMN chain in conjunction with the chest wall and supraclavicular region should be considered only for those with pathologically proven IMNs with the goal of improving tumor regional control.

Ipsilateral breast tumor recurrence following breast-conserving surgery for early-stage invasive cancer

Ipsilateral breast tumor recurrence (IBTR) following conservative surgery and radiation for early stage invasive cancer occurs in approximately 15% of all patients at 10 years and is diminished with surgical excisions which achieve negative margins. Treatment strategies of breast-conserving surgery with or without radiation that result in IBTR rates of 30 40% will impact negatively on survival and the magnitude of this effect will be influenced by the predominant pattern of local failure as well as initial and subsequent distant metastases. Optimal local control in early-stage invasive breast cancer is important to minimize the risk of a salvage mastectomy and maximize the potential for long-term survival.

Patients with early stage invasive cancer with close or positive margins treated with conservative surgery and radiation have an increased risk of breast recurrence that is delayed by adjuvant systemic therapy

PURPOSE

The association between a positive resection margin and the risk of ipsilateral breast tumor recurrence (IBTR) after conservative surgery and radiation is controversial. The width of the resection margin that minimizes the risk of IBTR is unknown. While adjuvant systemic therapy may decrease the risk of an IBTR in all patients, its impact on patients with positive or close margins is largely unknown. This study examines the interaction between margin status, margin width, and adjuvant systemic therapy on the 5- and 10-year risk of IBTR after conservative surgery and radiation.

METHODS AND MATERIALS

A series of 1,262 patients with clinical Stage I or II breast cancer were treated by breast-conserving surgery, axillary node dissection, and radiation between March 1979 and December 1992. The median follow-up was 6.3 years (range 0.1-15.6). The median age was 55 years (range 24-89). Clinical size was T1 in 66% and T2 in 34%. Seventy-three percent of patients were node-negative. Only 5 % of patients had tumors that were EIC-positive. Forty-one percent had a single excision, and 59% had a reexcision. The final margins were negative in 77%, positive in 12%, and close (< or = 2 mm) in 11%. The median total dose to the tumor bed was 60 Gy with negative margins, 64 Gy with close margins, and 66 Gy with positive margins. Chemotherapy +/- tamoxifen was used in 28%, tamoxifen alone in 20%, and no adjuvant systemic therapy in 52%.

RESULTS

The 5-year cumulative incidence (CI) of IBTR was not significantly different between patients with negative (4%), positive (5%), or close (7%) margins. However, by 10 years, a significant difference in IBTR became apparent (negative 7%, positive 12%, close 14%, p = 0.04). There was no significant difference in IBTR when a close or positive margin was involved by invasive tumor or DCIS. Reexcision diminished the IBTR rate to 7% at 10 years if the final margin was negative; however, the highest risk was observed in patients with persistently positive (13%) or close (21%) (p = 0.02) margins. The median interval to failure was 3.7 years after no adjuvant systemic therapy, 5.0 years after chemotherapy +/- tamoxifen, and 6.7 years after tamoxifen alone. This delay to IBTR was observed in patients with close or positive margins, with little impact on the time to failure in patients with negative margins. The 5-year CI of IBTR in patients with close or positive margins was 1% with adjuvant systemic therapy and 13% with no adjuvant therapy. However, by 10 years, the CI of IBTR was similar (18% vs. 14%) due to more late failures in the patients who received adjuvant systemic therapy.

CONCLUSION

A negative margin (> 2 mm) identifies patients with a very low risk of IBTR (7% at 10 years) after conservative surgery and radiation. Patients with a close margin (< or = 2 mm) are at an equal or greater risk of IBTR as with a positive margin, especially following a reexcision. A margin involved by DCIS or invasive tumor has the same increased risk of IBTR. A reexcision of an initially close or positive margin that results in a negative final margin reduces the risk of IBTR to that of an initially negative margin. A close or positive margin is associated with an increased risk of IBTR even in patients who are EIC-negative or receiving higher boost doses of radiation. The median time to IBTR is delayed; however, the CI is not significantly decreased by adjuvant systemic therapy in patients with close or positive margins-the 5 year results in these patients underestimate their ultimate risk of recurrence.

Postmastectomy radiation in patients with one to three positive axillary nodes receiving adjuvant chemotherapy: An unresolved issue

The rationale for postmastectomy radiation is based on the prevention of locoregional recurrence in the chest wall, regional lymphatics, or both. The randomized trials of postmastectomy radiation in patients with one to three positive nodes receiving adjuvant chemotherapy have shown a proportional reduction in locoregional recurrence rates of two thirds. The absolute benefit, however, varies with the magnitude of the risk in patients who do not receive radiation. The survival benefit from radiation is best explained by the prevention of an isolated locoregional recurrence, which could serve as a source of fatal distant metastases and parallels the difference in the total incidence of distant metastases. The current dilemma is to identify patients with one to three positive nodes who have had an adequate axillary dissection and remain at substantial risk for a locoregional recurrence despite adjuvant chemotherapy. The routine use of postmastectomy radiation in all axillary node-positive patients requires further evaluation.

Postmenopausal hormone replacement therapy: effect on diagnosis and outcome in early-stage invasive breast cancer treated with conservative surgery and radiation

PURPOSE

To compare the pretreatment characteristics and outcome of postmenopausal women with stage I-II breast cancer treated with conservative surgery and radiation who had a history of hormone replacement therapy (HRT) with those who had never received HRT.

MATERIALS AND METHODS

From 1979 to 1993, 485 postmenopausal women underwent excisional biopsy, axillary dissection, and radiation for stage I-II breast cancer. The median follow-up was 5.9 years. One hundred forty-one patients reported a history of HRT. The median length of use was 5 years. Three hundred forty-four patients reported no history of HRT.

RESULTS

Statistically significant differences between the two groups were observed for median age (HRT 60 years v no HRT 64 years; P =.0009), median weight (HRT 142 lbs v no HRT 152 lbs; P =.004), clinical tumor size < or = 2 cm (HRT 77% v no HRT 66%; P =.02), and the use of re-excision (HRT 62% v no HRT 49%; P =.01). The method of detection by mammogram only (HRT 52% v no HRT 42%; P =.06) was of borderline statistical significance. The HRT patients had a statistically significant increased cumulative incidence of ipsilateral breast tumor recurrence (8% v 2%; P =.02), a statistically significant decreased cumulative incidence of distant metastases (HRT 6% v no HRT 17%; P =.01), and a borderline statistically significant improvement in cause-specific survival at 10 years (HRT 92% v no HRT 86%; P =.07). Postmenopausal women with a history of HRT did not have an increased risk of contralateral breast cancer or second non-breast cancer malignancy.

CONCLUSION

This study failed to identify an adverse effect of HRT on breast cancer mortality in patients with stage I-II disease treated with conservative surgery and radiation.

Locoregional failure 10 years after mastectomy and adjuvant chemotherapy with or without tamoxifen without irradiation: experience of the Eastern Cooperative Oncology Group

PURPOSE

To assess patterns of failure and how selected prognostic and treatment factors affect the risks of locoregional failure (LRF) after mastectomy in breast cancer patients with histologically involved axillary nodes treated with chemotherapy with or without tamoxifen without irradiation.

PATIENTS AND METHODS

The study population consisted of 2,016 patients entered onto four randomized trials conducted by the Eastern Cooperative Oncology Group. The median follow-up time for patients without recurrence was 12.1 years (range, 0.07 to 19.1 years).

RESULTS

A total of 1,099 patients (55%) experienced disease recurrence. The first sites of failure were as follows: isolated LRF, 254 (13%); LRF with simultaneous distant failure (DF), 166 (8%); and distant only, 679 (34%). The risk of LRF with or without simultaneous DF at 10 years was 12.9% in patients with one to three positive nodes and 28.7% for patients with four or more positive nodes. Multivariate analysis showed that increasing tumor size, increasing numbers of involved nodes, negative estrogen receptor protein status, and decreasing number of nodes examined were significant for increasing the rate of LRF with or without simultaneous DF.

CONCLUSION

LRF after mastectomy is a substantial clinical problem, despite the use of chemotherapy with or without tamoxifen. Prospective randomized trials will be necessary to estimate accurately the potential disease-free and overall survival benefits of postmastectomy radiotherapy for patients in particular prognostic subgroups treated with presently used and future systemic therapy regimens.

The presence of proliferative breast disease with atypia does not significantly influence outcome in early-stage invasive breast cancer treated with conservative surgery and radiation

PURPOSE

To evaluate the influence of the benign background breast-tissue change of atypical hyperplasia (AH) on outcome in patients with early-stage invasive breast cancer treated with conservative surgery and radiation.

MATERIALS AND METHODS

Four hundred and sixty women with Stage I--II breast cancer treated with conservative surgery and radiation from 1982-1994 had pathologic assessment of their background adjacent benign breast tissue. The median follow-up was 5.6 years (range 0.1-15). The median age was 55 years (range 24-88). Of these, 23% had positive axillary nodes; 25% received adjuvant chemotherapy (CMF or CAF) with (9%) or without (17%) tamoxifen. Of the total, 24% received adjuvant tamoxifen alone. The patients were divided into 2 groups: 131 patients with atypical hyperplasia (ductal, 99 patients; lobular, 20 pts; and type not specified, 12 pts), and 329 patients with no proliferative changes or proliferative changes without atypia.

RESULT

A statistically significant difference was observed between the 2 groups for method of detection, primary tumor size, presence of lobular carcinoma in situ (LCIS), pathologic nodal status, region(s) treated with radiation, and type of adjuvant therapy. Patients with atypical hyperplasia (AH) had smaller primary tumors (T1 80% vs. 70%) more often detected solely by mammography (51% vs. 36%) with negative axillary nodes (87% vs. 73%) and radiation treatment to the breast only (93% vs. 78%). LCIS was observed in 9% of the patients with AH and 3% of those without AH. Patients with AH more often received tamoxifen alone (32% vs. 21%), rather than chemotherapy (15% vs. 29%). There were no statistically significant differences between the 2 groups for race, age, menopausal status, family history, histology, histologic subtype DCIS when present, the presence or absence of an extensive intraductal component, final margin status, estrogen or progesterone receptor status, use of re-excision, or total radiation dose to the primary. The 5- and 10-year actuarial ipsilateral breast tumor recurrence rates were 2% and 12% for patients with AH and 4% and 8% for those without AH (p=0.44). Younger women or those with a positive family history of breast cancer with AH did not have an increased rate of breast failure when compared to similar patients without AH. There were no significant differences in the 5- and 10-year actuarial rates of distant metastases (AH 5- and 10-year 7% and 7%, no AH 5- and 10-year 8% and 16%,p=0.31), regional node recurrence (AH 1% and 1%, no AH 1% and 1%,p=0.71), contralateral breast cancer (AH 3% and 3%, no AH 3% and 8%,p=0.71), overall survival (AH 95% and 86%, no AH 95% and 89%, p=0.79), or cause-specific survival (AH 98% and 95%, no AH 96% and 91%,p=0.27). Subset analysis for ipsilateral breast tumor recurrence, distant metastases, overall, and cause-specific survival for T1 vs. T2 tumors and path node-negative vs. path node-positive patients revealed no significant differences between the 2 groups.

CONCLUSION

AH was not associated with an increased risk of ipsilateral breast tumor recurrence or contralateral breast cancer in this study of patients with invasive breast cancer treated with conservative surgery and radiation. Therefore, the presence of proliferative changes with atypia in background benign breast tissue should not be a contraindication to breast-conservation therapy.

Lung and heart dose volume analyses with CT simulator in radiation treatment of breast cancer

PURPOSE

Radiation pneumonitis and cardiac effects are directly related to the irradiated lung and heart volumes in the treatment fields. The central lung distance (CLD) from a tangential breast radiograph is shown to be a significant indicator of ipsilateral irradiated lung volume. Retrospective analysis of the pattern of dose volume of lung and heart with actual volume data from a CT simulator in the treatment of breast cancer is presented with respect to CLD.

METHODS AND MATERIALS

The heart and lung volumes in the tangential treatment fields were analyzed in 108 consecutive cases (52 left and 56 right breast) referred for CT simulation. All patients in this study were immobilized and placed on an inclined breast board in actual treatment setup. Both arms were stretched over head to avoid collision with the scanner aperture. Radiopaque marks were placed on the medial and lateral borders of the tangential fields. All patients were scanned in spiral mode with slice width and thickness of 3 mm each, respectively. The lung and heart structures as well as irradiated areas were delineated on each slice and respective volumes were accurately measured. The treatment beam parameters were recorded and the digitally reconstructed radiographs (DRRs) were generated for the measurement of the CLD and analysis.

RESULTS

Using CT data the mean volume and standard deviation of left and right lungs were 1307.7+/-297.7 cm3 and 1529.6+/-298.5 cm3, respectively. The magnitude of irradiated volume in left and right lung is nearly equal for the same CLD that produces different percent irradiated volumes (PIV). The left and right PIV lungs are 8.3+/-4.7% and 6.6+/-3.7%, respectively. The PIV data have shown to correlate with CLD with second- and third-degree polynomials; however, in this study a simple straight line regression is used to provide better confidence than the higher order polynomials. The regression lines for the left and right breasts are very different based on actual CT data. The slopes of regression lines for the left and right lung are 0.6%/mm and 0.5%/mm, respectively which is statistically different with thep value of 0.01. A maximum heart PIV of >3.0% is observed in 80% of the patients. The heart PIV is inversely correlated with gantry angle and weakly correlated with CLD.

CONCLUSIONS

The CT-simulator provides accurate volumetric information of the heart and lungs in the treatment fields. The lung PIV is directly correlated to the CLD (0.6%/mm and 0.5%/mm for the left and right lungs). Left and right lungs have different volumes and hence, different regression lines are recommended. An additional 12% lung volume could be irradiated in the supraclavicular field. Heart volume is not correlated with the CLD. The heart PIV is associated to the beam angle. Heart volume may not be accurately visualized in a tangential radiograph; however, this can be easily seen in a DRR with contour delineation and can be minimized with proper beam parameters iteratively with a virtual simulator. Lung and heart PIV along with dose volume histograms (DVH) are essential in reducing pulmonary and cardiac complications.

Evidence for selective use of bone scans in early stage breast cancer

To determine the usefulness of bone scans in detecting metastatic disease in women with early stage breast cancer, records of 193 patients who had bone scans preformed and underwent breast conservation therapy at a single institution were reviewed. Patients with invasive T1 or T2 breast carcinomas were eligible for this study; patients with a true positive bone scan were excluded from conservation therapy and, thus, were excluded from this study. The incidence of false positive bone scans in this study population was 32.6% (63/193 patients). Patients over 50 years of age had a significantly greater incidence of false positive bone scans (p<0. 05). In the 63 patients with false positive bone scans, 101 radiographs were performed to exclude metastatic disease in areas of increased uptake identified on bone scan. No significant difference in the rate of false positive bone scans was seen in relation to tumor size, pathologic or clinical nodal status or hormone receptor activity of the primary tumor. Thus, selective use of bone scans is advocated in patients with early stage (T1 or T2) breast cancer.

A close or positive margin after mastectomy is not an indication for chest wall irradiation except in women aged fifty or younger

INTRODUCTION

Indications for postmastectomy radiation include primary tumor size > or = 5 cm and/or > or = 4 positive axillary nodes. In clinical practice, patients with a close or positive margin after mastectomy are also often treated with postmastectomy radiation. However, there is little data regarding the risk of a chest wall recurrence in patients with close or positive margins who otherwise would be considered low risk (tumor size <5 cm and/or 0-3 positive nodes). To address this issue, we assessed the risk of a chest wall recurrence in women with Stage I-II breast cancer who underwent mastectomy and were found to have primary tumor size <5 cm and 0-3 positive nodes with a close or positive deep margin.

METHODS AND MATERIALS

The pathologic reports from 789 patients treated by mastectomy between 1985 and 1994 at our institution were retrospectively reviewed. Of these, 136 (17%) had tumor within 1 cm of the deep resection margin. The study population consists of 34 of these patients with close or positive margins whose primary tumor size was <5 cm with 0-3 positive axillary nodes and who received no postoperative radiation. The median age was 43 years (range 29-76). Of these, 44% had T1 tumors and 56% T2 tumors. Pathologic axillary nodal status was negative in 65% and positive in 35%. The median number of positive nodes was 1. The deep margin was positive in 2 patients, < or = 2 mm in 17 patients, 2.1-4 mm in 7 patients and 4.1-6 mm in 8 patients. Of the 34 patients, 67% received adjuvant chemotherapy +/- tamoxifen and 21% received tamoxifen alone. The median follow-up was 59 months (range 7-143).

RESULTS

There were 5 chest wall recurrences at a median interval of 26 months (range 7-127). One was an isolated first failure, one occurred concurrent with an axillary recurrence, and three were associated with distant metastases. The 5- and 8-year cumulative incidences of a chest wall recurrence were 9% and 18%. Patient age correlated with the cumulative incidence of chest wall recurrence at 8 years; age < or = 50 years had a rate of 28% vs. 0% for age >50 (p = 0.04). There was no correlation with chest wall failure and number of positive nodes, ER status, lymphovascular invasion, location of primary, grade, family history, or type of tumor close to the margin. Of 5 chest wall failures, 4 were in patients who had received adjuvant systemic chemotherapy +/- tamoxifen. Chest wall failures occurred in 1 patient with a positive deep margin, 3 patients with margins within 2 mm, and 1 patient with a margin of 5 mm. The estimated cumulative incidence probability of chest wall recurrence at 8 years by margin proximity was 24% < or = 2 mm vs. 7% 2.1-6 mm (p = 0.36), and by clinical size 24% for T2 tumors vs. 7% for T1 (p = 0.98).

CONCLUSIONS

A close or positive margin is uncommon (< or = 5%) after mastectomy in patients with tumor size <5 cm and 0-3 positive axillary nodes but, when present, it appears to be in a younger patient population. The subgroup of patients aged 50 or younger with clinical T1-T2 tumor size and 0-3 positive nodes who have a close (< or = 5 mm) or positive mastectomy margin are at high risk (28% at 8 years) for chest wall recurrence regardless of adjuvant systemic therapy and, therefore, should be considered for postmastectomy radiation.

Use of the prone position in radiation treatment for women with early stage breast cancer

PURPOSE

The prone position has been advocated for women with large pendulous breasts undergoing breast-conserving treatment with radiation therapy. However, there is no information in the literature regarding the coverage of the target volume with this technique. The purpose of this study was to evaluate the effectiveness of the prone treatment position in including at least the biopsy cavity with a 2-cm margin.

METHODS AND MATERIALS

Eleven consecutive patients who underwent CT simulation in the prone position were included in this study. Patients underwent CT simulation in the prone position using a flat platform containing an aperture for the breast to hang through in a dependent fashion. CT slices were 5-mm thick taken at 3-mm intervals. The biopsy cavity was localized and outlined on sequential CT images using the surgical clips (when present) as well as the residual seroma. A 2-cm margin was included around the biopsy cavity to define the minimal target volume (mTV). Lateral fields were used for treatment planning. The beam arrangements were considered adequate if the mTV was totally included in the lateral fields.

RESULTS

Median age of the patient population was 55 years. Bra sizes ranged from 36A-44DD. The majority of patients had mammographically detected T1 lesions. Median volume of the biopsy cavity was 48 cm3. Five of 11 (45%) patients underwent reexcision of the biopsy cavity, and 6 of 11 (55%) had surgical clips placed in the biopsy cavity. Overall, 8 of 11 (73%) patients did not have the entire mTV included in the lateral opposed tangential fields in the prone position. This was especially true in patients whose biopsy cavity extended down to the chest wall. There were no other clinical factors that could predict for the adequacy of coverage in the prone position.

CONCLUSION

Special attention must be paid to the location of the surgical clips to determine the proximity of the biopsy cavity to the chest wall, or CT simulation should be performed to determine the exact location of the biopsy cavity prior to selecting patients with large pendulous breasts for treatment in the prone position.

Results of conservative surgery and radiation for mammographically detected ductal carcinoma in situ (DCIS)

PURPOSE

The role of conservative surgery and radiation for mammographically detected ductal carcinoma in situ (DCIS) is controversial. In particular, there is little data for outcome with radiation in a group of patients comparable to those treated with local excision and surveillance (mammographic calcifications < or = 2.5 cm, negative resection margins, negative postbiopsy mammogram). This study reports outcome of conservative surgery and radiation for mammographically detected DCIS with an emphasis on results in patients considered candidates for excision alone.

METHODS AND MATERIALS

From 1983 to 1992, 110 women with mammographically detected DCIS (77% calcifications +/- mass) and no prior history of breast cancer underwent needle localization and biopsy with (55%) or without a reexcision and radiation. Final margins of resection were negative in 62%, positive 7%, close 11%, and unknown 20%. The median patient age was 56 years. The most common histologic subtype was comedo (54%), followed by cribriform (22%). The median pathologic tumor size was 8 mm (range 2 mm to 5 cm). Forty-seven percent of patients with calcifications only had a negative postbiopsy mammogram prior to radiation. Radiation consisted of treatment to the entire breast (median 50.00 Gy) and a boost to the primary site (97%) for a median total dose of 60.40 Gy.

RESULTS

With a median follow-up of 5.3 years, three patients developed a recurrence in the treated breast. The median interval to recurrence was 8.8 years and all were invasive cancers. Two (67%) occurred outside the initial quadrant. The 5- and 10-year actuarial rates of recurrence were 1 and 15%. Cause-specific survival was 100% at 5 and 10 years. Contralateral breast cancer developed in two patients. There were too few failures for statistical significance to be achieved with any of the following factors: patient age, family history, race, mammographic findings, location primary, pathologic size, histologic subtype, reexcision, or final margin status. However, young age, positive or close margins, and the presence of a mass without calcifications had a trend for an increased risk of recurrence. There were no recurrences in the subset of 16 patients who would be candidates for surveillance by Lagios' criteria.

CONCLUSION

For selected patients, conservative surgery and radiation for mammographically detected DCIS results in a low risk of recurrence in the treated breast and 100% 5- and 10-year cause-specific survival. Improved mammographic and pathologic evaluation results in better patient selection and reduces the risk of the subsequent appearance of DCIS in the biopsy site. The identification of risk factors for an ipsilateral invasive breast recurrence is evolving.

Patterns of dose variability in radiation prescription of breast cancer

PURPOSE

Comparison of radiation outcome of various treatment protocols is difficult due to the variability of dose prescription. A retrospective analysis of the pattern and intercomparison of dose prescriptions is presented for the treatment of breast cancer.

MATERIALS AND METHODS

To represent the clinical practice for breast irradiation with tangential fields, commonly used prescription points were chosen that lie on the perpendicular bisector of the chest wall separation (s) that represents the breast apex height (h). These points are located at 1.5 cm from the posterior beam edge, at the chest wall-lung interface (2-3 cm), at distances of h/3 and h/2, and at the isocenter. One hundred consecutive patients treated with intact breast following excisional biopsy were used in this study. For analysis, treatment planning was carried out without lung correction with a 6 MV beam for all patients, even though some of the patients were treated with high energy beams for dose uniformity. Dose distributions were optimized with wedges and beam weights to provide a symmetrical dose distribution on the central axis plane. The statistical analyses of the different parameters, s, h, maximum dose, and doses at various prescription points were carried out.

RESULTS

The maximum dose (hot spot) in breast varied from +5% to +27% above the prescribed dose among the patient population. The hot spot was directly related to s, and appeared to be independent of h and the ratio h/s. Among 55%, 40%, and 5% of the patients, the magnitude of the hot spot was 5-10%, 10-15%, and >15%, respectively. Except for the magnitude of the hot spot, the doses at various prescription points were independent of the breast size. For a prescription point at h/3 or at the lung-chest wall interface, the dose variation within +/- 1% is observed for 90% of the patient population. On the other hand, the average dose variation is about +/- 3% among other protocols with dose prescription point varying up to the h/2 point. With the prescription point at the isocenter, an average and maximum variation of 4-5% and 11% were observed, respectively. The maximum dose inhomogeneity for some patients was significantly higher, i.e. up to +27% even without the lung correction.

CONCLUSIONS

A wide variation in prescription dose is observed among the different treatment protocols commonly used in breast treatment. For a total dose of 46-50 Gy delivered at 2 Gy/fraction to the breast, the prescribed dose may vary between 50 and 55 Gy and the hot spot dose per fraction may range between 2.3 and 2.5 Gy depending on the protocol and breast size. Thus dose normalization at hot spot and the isocenter should be discouraged unless the total dose to the breast is modified. A uniform definition of dose prescription for breast treatment is greatly required for intercomparison of clinical data.

Dosimetric comparison of treatment planning systems in irradiation of breast with tangential fields

PURPOSE

The objectives of this study are: (1) to investigate the dosimetric differences of the different treatment planning systems (TPS) in breast irradiation with tangential fields, and (2) to study the effect of beam characteristics on dose distributions in tangential breast irradiation with 6 MV linear accelerators from different manufacturers.

METHODS AND MATERIALS

Nine commercial and two university-based TPS are evaluated in this study. The computed tomographic scan of three representative patients, labeled as "small", "medium" and "large" based on their respective chest wall separations in the central axis plane (CAX) were used. For each patient, the tangential fields were set up in each TPS. The CAX distribution was optimized separately with lung correction, for each TPS based on the same set of optimization conditions. The isodose distributions in two other off-axis planes, one 6 cm cephalic and the other 6 cm caudal to the CAX plane were also computed. To investigate the effect of beam characteristics on dose distributions, a three-dimensional TPS was used to calculate the isodose distributions for three different linear accelerators, the Varian Clinac 6/100, the Siemens MD2 and the Philips SL/7 for the three patients. In addition, dose distributions obtained with 6 MV X-rays from two different accelerators, the Varian Clinac 6/100 and the Varian 2100C, were compared.

RESULTS

For all TPS, the dose distributions in all three planes agreed qualitatively to within +/- 5% for the "small" and the "medium" patients. For the "large" patient, all TPS agreed to within +/- 4% on the CAX plane. The isodose distributions in the caudal plane differed by +/- 5% among all TPS. In the cephalic plane in which the patient separation is much larger than that in the CAX plane, six TPS correctly calculated the dose distribution showing a cold spot in the center of the breast contour. The other five TPS showed that the center of the breast received adequate dose. Isodose distributions for 6 MV X-rays from three different accelerators differed by about +/- 3% for the "small" patient and more than +/- 5% for the "large" patient. For two different 6 MV machines of the same manufacturer, the isodose distribution agreed to within +/- 2% for all three planes for the "large" patient.

CONCLUSION

The differences observed among the various TPS in this study were within +/- 5% for both the "small" and the "medium" patients while doses at the hot spot exhibit a larger variation. The large discrepancy observed in the off-axis plane for the "large" patient is largely due to the inability of most TPS to incorporate the collimator angles in the dose calculation. Only six systems involved agreed to within +/- 5% for all three patients in all calculation planes. The difference in dose distributions obtained with three accelerators from different manufacturers is probably due to the difference in beam profiles. On the other hand, the 6 MV X-rays from two different models of linear accelerators from the same manufacturer have similar beam characteristics and the dose distributions are within +/- 2% of each other throughout the breast volume. In general, multi-institutional breast treatment data can be compared within a +/- 5% accuracy.

Identification of women with T1-T2 breast cancer at low risk of positive axillary nodes

BACKGROUND AND OBJECTIVES

The diagnostic and therapeutic significance of axillary dissection has been questioned. We sought to define a subgroup of patients with early-stage breast cancer who are at low risk for positive axillary nodes.

METHODS

Between 1970 and 1995, 1,598 women with stage I and II breast cancer underwent level I-II axillary dissection with a minimum of 10 nodes removed. The following factors were examined in univariate analysis for predicting positive nodes: race, method of detection, location of the primary tumor, age, menopausal status, obesity, ER status, PR status, pathologic tumor size, lymphatic vascular invasion, tumor grade, and histology.

RESULTS

Four hundred and forty-five of the 1,598 patients (27.8%) had histologically positive axillary nodes. Significant factors in univariate analysis for positive nodes included: tumor size, lymphatic vascular invasion, grade, method of detection, primary tumor location, and age. The only group of women with a 0% risk of axillary nodes were those in whom the pathologic tumor size was < or = 5 mm and mammographically detected. A 5-10% risk of positive axillary nodes was identified in women with (1) pathologic tumor size 6-10 mm, mammographically detected, and age < or = 40 years, and (2) tubular carcinoma < or = 10 mm. Tumors detected on physical examination with or without mammography and women < or = 40 years had a significantly increased risk of nodes. In multivariate analysis lymphatic vascular invasion (P < 0.001), method of detection (P = 0.026), location (P = 0.01), and pathologic tumor size (P = 0.002) were significant predictors of positive axillary lymphadenopathy.

CONCLUSIONS

The decision to forego an axillary dissection should be considered in (1) tumors mammographically detected and < or = 5 mm (2) mammographically detected, pathologic size 6-10 mm, age > 40 and (3) tubular carcinoma < or = 10 mm. All other groups had a > 10% risk of nodes and may benefit from axillary dissection.

Dose estimation to critical organs from vertex field treatment of brain tumors

PURPOSE

Radiation management of intracranial tumors may require a noncoplanar vertex field that often irradiates the entire length of the body. In view of radiation related risks to the normal tissues dose estimation to the extracranial organs such as the thyroid gland, spinal cord, heart, and genitalia is performed for a vertex field.

METHODS AND MATERIALS

A vertex field used clinically was reproduced on an anthropomorphic Rando phantom to measure radiation dose to various organs in the primary beam. Three photon beams (4, 6, and 10 MV), and two high energy electron beams (16 and 20 MeV) were used. Dosimetry was performed with an ion chamber sandwiched between phantom slices at the appropriate positions. All doses were normalized to the target dose at a depth of 5 cm. The effect of the head position was studied by rotating the gantry angle up to +/-20 degrees to mimic the extension and flexion of the head. Theoretical calculation was performed using an exponential best fit to the depth dose table to estimate the dose to various points and compare with the measured dose.

RESULTS

The measured normalized dose to the cervical cord, thyroid, heart, and female and male gonads are 60, 36, 16, 2.5, and 1.6%, respectively, for a 6 MV photon beam. The dose from 4 MV and 10 MV are slightly lower and higher, respectively. Doses from electron beams are about a factor of 4-10 lower than those of the photon beams. The measured gonadal dose from the primary beam is <5% of the target dose for all energies used in the study. The actual value, however, is dependent on the body structure, length, and the posture of the patient. A +5 degree head flexion had little effect on the dose to the various parts of the body. The head rotations greater than +/-10 degrees produced relatively lower doses by a factor of 10(-2) to the organs at distances greater than 40 cm from the prescription point. The radiation doses to the different critical organs estimated from the fitted curves are lower than the measured doses up to 35%.

CONCLUSIONS

When a vertex field is used for the treatment of the brain tumors, the entire axial length of the body is irradiated which adds to the integral dose. Unlike the scattered and leakage radiation, the primary dose to extracranial critical organs is greater for higher energies. For a 10 MV beam the ovary and testis at a distance of 80 cm and 90 cm may receive a dose of 4.2 and 3%, respectively, of the target dose. The gonadal dose could be quite significant if the entire treatment is delivered using a vertex field. For pediatric and smaller patients, dose to the critical organs at known distances could be estimated from the empirical equation obtained from the measured data. While the risk-benefit ratio is often evaluated and acceptable for treating malignant tumors, the long-term complications need thorough assessment in younger and curable patients. In view of radiation carcinogenesis and genetic burden, dose reduction to critical organs should be considered using a 3D planning system to arrange beams in other nonaxial planes and by considering electron beams for the vertex field.

Postmastectomy radiation: then and now

With the increased use of doxorubicin-based chemotherapy, chemoendocrine therapy, and high-dose chemotherapy with autologous bone marrow transplantation or peripheral blood progenitor-cell reinfusion, the role of postmastectomy radiation in the treatment of stages II-III breast cancer has been challenged. Despite these therapies, 20% to 30% of patients with four or more positive nodes, primary tumor size > or = 5 cm, or pectoral fascia involvement will develop an isolated locoregional recurrence. Postmastectomy radiation decreases the incidence of locoregional recurrence to < or = 10% in these high-risk patients, and modifications in technique can minimize long-term cardiac mortality. A recent meta-analysis has demonstrated a decrease in breast cancer mortality of approximately 10% with postmastectomy radiation, which is similar to the effect of adjuvant systemic therapy in axillary node-positive patients. Future studies are needed to further define the subset of patients who will benefit from postmastectomy radiation and to more precisely quantitate this benefit.

Effect of low-density lateral interfaces on soft-tissue doses

PURPOSE

Doses at the interface between tissue and low-density inhomogeneities with the interface positioned perpendicular to the beam direction have been well studied. When the inhomogeneity lies parallel to the beam direction (i.e., a lateral interface), the resulting dose distribution is not as well known. Lateral lung-soft-tissue interfaces are common in many fields used to treat malignancies in the thorax region including tangential breast fields and anteroposterior fields for lung and esophageal cancer. The purpose of this study was to evaluate the dose distribution along lateral interfaces and to determine the implications for treatment.

METHODS AND MATERIALS

A polystyrene and cork slab phantom was irradiated from the side to simulate treatment fields with lateral lung-soft-tissue interfaces. The beam was positioned with the isocenter in polystyrene and the field edge in cork. Cork slabs (0.6-2.5 cm) were used to simulate different thicknesses of lung between the field edge and the target volume. Measurements were made using a parallel plate ionization chamber. With the chamber position held constant, polystyrene slabs were added between the cork and the chamber to study the dose distribution in the interface region. Interface doses were studied as a function of the amount of cork in the field, field size, beam energy (6-18 MV), and depth.

RESULTS

Doses in the interface region were lower by as much as 10% compared to doses in a homogeneous phantom. For a given cork width and field size, the magnitude of the underdose increased by several percent as the x-ray energy increased from 6 to 18 MV. The underdose at the interface was 5% for 6 MV and 8% for 18 MV X-rays with a 1-cm cork width. For a 2.5-cm cork width, underdoses of 2.5% and 3% at distances up to 2.5 and 4 mm lateral to the interface were observed for 6- and 18-MV X-rays, respectively. However, doses right at the interface were 1% greater for 6 MV and 3% less for 18 MV than doses in a homogeneous phantom. For a given cork width, the interface doses were not significantly dependent on field width but decreased by an additional 2-3% as the length decreased to 4 cm. Additional decreases were also observed when the measurement depth decreased to 3 cm. With a 1-cm width of cork in the field, a lateral distance of 3-4 mm from the interface was necessary to ensure doses of at least 98% of the homogenous dose with 6-MV X-rays. A lateral distance of 6-7 mm was necessary for 10- and 18-MV X-rays.

CONCLUSION

Underdosing will occur in the soft tissues adjacent to low-density inhomogeneities. The magnitude depends primarily on the width of the inhomogeneity seen in the treatment field, but also on field size, depth, and beam energy. For treatment fields with a lateral lung interface, a segment of tissue approximately 3-4 mm thick for 6 MV and 6-7 mm thick for higher-energy beams may be underdosed. Lung widths of > or = 1.75 cm as observed on film will generally guarantee doses of at least 96% of those calculated with no inhomogeneity corrections. High-energy beams are often used to treat sites in the thorax or breast to improve dose homogeneity throughout the treatment volume. Potential underdosing due to the presence of lung should be considered and may require a decrease in beam energy or an increase in the margin between the target volume and the field edge to ensure adequate treatment.

The value of setup portal films as an estimate of a patient's position throughout fractionated tangential breast irradiation: an on-line study

PURPOSE

To determine if portal setup films are an accurate representation of a patient's position throughout the course of fractionated tangential breast irradiation.

METHODS AND MATERIALS

Thirteen patients undergoing external beam irradiation for T1-T2 infiltrating ductal carcinoma of the breast following excisional biopsy and axillary dissection were imaged using an on-line portal imaging device attached to a 6 MV linear accelerator. Medial and lateral tangential fields were imaged and a total of 139 fractions, 225 portal fields, and 4450 images were obtained. Interfractional and intrafractional variations for anatomical parameters including the central lung distance (CLD), central flash distance (CFD), and inferior central margin (ICM) were calculated from these images. A pooled estimate of the random error associated with a given treatment was determined by adding the interfractional and intrafractional standard deviations in quadrature. A 95% confidence level assigned a value of two standard deviations of the random error estimate. Central lung distance, CFD, and ICM distances were then measured for all portal setup films. Significant differences were defined as occurring when the simulation-setup difference was greater than the 95% confidence value.

RESULTS

Differences between setup portal and simulation films were less than their 95% confidence values in 70 instances indicating that in 90% of the time these differences are a result of random differences in daily treatment positioning.

CONCLUSIONS

In 90% of cases tested, initial portal setup films are an accurate representation of a patients daily treatment setup.

Treatment planning for primary breast cancer: a patterns of care study

PURPOSE

The 1989 Patterns of Care Study included treatment planning for early breast cancer. A Consensus Committee of radiation physicists and oncologists determined current guidelines and developed questionnaires to determine treatment planning and delivery processes used by the participating institutions (e.g., use of portal films). This article presents and analyzes the results of that survey.

METHODS AND MATERIALS

The survey included 449 respondents, distributed as follows: 136 (30%) from Strata I (academic facilities); 169 (38%) from Strata II (hospital based facilities); and 144 (32%) from Strata III (freestanding facilities). The treatment planning procedures surveyed included: whether individualized tissue compensators are used, whether inhomogeneity corrections are used in dose calculations, the use of computerized tomography, whether isodose distributions for external beam tangents and interstitial implants are generated, the use of lymphoscintigraphy, immobilization devices, simulations, portal films, etc.

RESULTS

The survey results demonstrated that out of 305 patients from Strata I and II institutions, 237 (78%) had simulated tangential fields. Consistent with this finding is that 76% of patients from Strata I and II institutions were immobilized, while only 51% of Strata III patients were. Moreover, only 18 out of the 449 (4%) of cases did not have any type of external beam dose distribution calculated--presumably, in these cases missing tissue compensation would be unlikely. On the other hand, 41% of the Strata II, 27% of Strata III, but only 19% of Strata I (p < 0.0002) cases received CT. Surprisingly, 19% of the Strata I, 35% of the Strata II, and 25% of the Strata III (p = 0.0011) patients received lymphoscintigraphy, perhaps reflecting the use of wide tangents to encompass the internal mammary nodes in these patients. In terms of optimizing treatments, 74% of Strata I, 70% of Strata II, and 78% of Strata III patients had wedges used on both tangential fields, although in 5, 12, and 14%, respectively, no beam modification of any sort was used. Furthermore, it should be noted that in 7% of the Strata I, 23% of Strata II, and 37% of Strata III cases there was no attempt to reduce the divergence of the tangential fields into the lung. On the other hand, if one considers the 135 (of 449) patients where matching of the tangential and supraclavicular fields was applicable, 41% of Strata I, 22% of Strata II and 46% of Strata III patients had those fields matched in a vertical plane, which would involve sophisticated alignment procedures. Quality control of treatment delivery was high: 97% of all surveyed received portal films at least once. The use of thermoluminescent dosimetry (TLD) to measure the dose to the contralateral breast was of little interest: only 4 of the 305 Strata I and II patients received in vivo measurements.

CONCLUSIONS

This national survey has established the patterns of treatment planning for early breast cancer. It shows a generally consistent approach-although a number of statistically significant variations have been identified.

The impact of tamoxifen on breast recurrence, cosmesis, complications, and survival in estrogen receptor-positive early-stage breast cancer

PURPOSE

To evaluate the impact of tamoxifen on breast recurrence, cosmesis, complications, overall and cause-specific survival in women with Stage I-II breast cancer and estrogen receptor positive tumors undergoing conservative surgery and radiation.

METHODS AND MATERIALS

From 1982 to 1991, 491 women with estrogen receptor positive Stage I-II breast cancer underwent excisional biopsy, axillary dissection, and radiation. The median age of patient population was 60 years with 21% < 50 years of age. The median follow-up was 5.3 years (range 0.1 to 12.8). Sixty-nine percent had T1 tumors and 83% had histologically negative axillary nodes. Re-excision was performed in 49% and the final margin of resection was negative in 64%. One hundred fifty-four patients received tamoxifen and 337 patients received no adjuvant therapy. None of the patients received adjuvant chemotherapy.

RESULTS

There were no significant differences between the two groups for age, race, clinical tumor size, histology, the use of re-excision, or median total dose to the primary. Patients who received tamoxifen were more often axillary node positive (44% tamoxifen vs. 5% no tamoxifen), and, therefore, a greater percentage received treatment to the breast and regional nodes. The tamoxifen patients less often had unknown margins of resection (9% tamoxifen vs. 22% no tamoxifen). The 5-year actuarial breast recurrence rate was 4% for the tamoxifen patients compared to 7% for patients not receiving tamoxifen (p = 0.21). Tamoxifen resulted in a modest decrease in the 5-year actuarial risk of a breast recurrence in axillary node-negative patients, in those with unknown or close margins of resection, and in those who underwent a single excision. Axillary node-positive patients had a clinically significant decrease in the 5-year actuarial breast recurrence rate (21 vs. 4%; p = 0.08). The 5-year actuarial rate of distant metastasis was not significantly decreased by the addition of adjuvant tamoxifen in all patients or pathologic node-negative patients. Pathologically node-positive patients had a significant decrease in distant metastasis (35 vs. 11%; p = 0.02). There were no significant differences in cause-specific survival for patients receiving tamoxifen when compared to observation (95% no tamoxifen vs. 89% tamoxifen; p = 0.24). Similar findings were noted for pathologically node-negative patients. However, axillary node-positive patients receiving tamoxifen had an improvement in 5-year actuarial cause-specific survival (90% tamoxifen vs. 70% no tamoxifen; p = 0.10). Cosmesis (physician assessment) was good to excellent in 85% of the tamoxifen patients compared to 88% of the patients who did not receive tamoxifen.

CONCLUSION

The addition of tamoxifen to conservative surgery and radiation in women with Stage I-II breast cancer and estrogen receptor positive tumors resulted in a modest but not statistically significant decrease in the 5-year actuarial risk of a breast recurrence. Tamoxifen significantly decreased the 5-year actuarial risk of distant metastasis in axillary node-positive patients and there was a trend towards improvement in cause-specific survival that was not statistically significant. Tamoxifen did not decrease the 5-year actuarial rate of distant metastasis in axillary node negative, patients and in this group, there was no improvement in cause-specific survival. Tamoxifen did not have an adverse effect on cosmesis or complications.