Impact of boost technique on outcome in early-stage breast cancer patients treated with breast-conserving therapy

Breast Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

The therapeutic options for patients with noninvasive or invasive breast cancer are complex and varied. These NCCN Clinical Practice Guidelines for Breast Cancer include recommendations for clinical management of patients with carcinoma in situ, invasive breast cancer, Paget disease, phyllodes tumor, inflammatory breast cancer, and management of breast cancer during pregnancy. The content featured in this issue focuses on the recommendations for overall management of ductal carcinoma in situ and the workup and locoregional management of early stage invasive breast cancer. For the full version of the NCCN Guidelines for Breast Cancer, visit NCCN.org.

Comparison of the Oncological Efficacy Between Intraoperative Radiotherapy With Whole-Breast Irradiation for Early Breast Cancer: A Meta-Analysis

Background

Intraoperative radiotherapy (IORT) and whole-breast irradiation (WBI) are both effective radiotherapeutic interventions for early breast cancer patients undergoing breast-conserving surgery; however, an issue on whether which one can entail the better prognosis is still controversial. Our study aimed to investigate the 5-year oncological efficacy of the IORT cohort and the WBI cohort, respectively, and compare the oncological efficacy between the cohorts.

Materials and Methods

We conducted a computerized retrieval to identify English published articles between 2000 and 2021 in the PubMed, the Web of Science, the Cochrane Library, and APA PsycInfo databases. Screening, data extraction, and quality assessment were performed in duplicate.

Results

A total of 38 studies were eligible, with 30,225 analyzed participants. A non-comparative binary meta-analysis was performed to calculate the weighted average 5-year local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and overall survival (OS) in the two cohorts, respectively. The LRFS, DMFS, and OS (without restriction on the 5-year outcomes) between the two cohorts were further investigated by a comparative binary meta-analysis. The weighted average 5-year LRFS, DMFS, and OS in the IORT cohort were 96.3, 96.6, and 94.1%, respectively, and in the WBI cohort were 98.0, 94.9, and 94.9%, respectively. Our pooled results indicated that the LRFS in the IORT cohort was significantly lower than that in the WBI cohort (pooled odds ratio [OR] = 2.36; 95% confidential interval [CI], 1.66–3.36). Nevertheless, the comparisons of DMFS (pooled OR = 1.00; 95% CI, 0.76–1.31), and OS (pooled OR = 0.95; 95% CI, 0.79–1.14) between the IORT cohort with the WBI cohort were both not statistically significant.

Conclusions

Despite the drastically high 5-year oncological efficacy in both cohorts, the LRFS in the IORT cohort is significantly poorer than that in the WBI cohort, and DMFS and OS do not differ between cohorts.

A comparison of a brachytherapy and an external beam radiotherapy boost in breast-conserving therapy for breast cancer: local and any recurrences

PURPOSE

Adding a tumour bed boost to whole-breast irradiation in breast-conserving therapy reduces local recurrence rates. The purpose of the present study was to investigate whether the boost technique influences the magnitude of the effect.

METHODS

Patients treated with breast-conserving therapy for invasive breast cancer between 2000 and 2007 were included in the analysis. Three groups were considered according to the applied boost technique: electrons, brachytherapy or photons. The endpoints were local recurrence and any recurrence. Cox regression models were used and correction for the confounders in the association between boost technique and outcome was performed using multivariable models.

RESULTS

1879 tumours were included in the analysis. 1448 tumours (77.1%) were treated with an electron boost, 334 (17.8%) with a brachytherapy boost and 97 (5.2%) with a photon boost. Median follow-up was 13.1 years. The 10-year local recurrence rate was 2.2%. In multivariable analysis with correction for age, pathological Tumour or Node stage (pT, pN), chemotherapy and hormonal therapy, there was no significant difference between the three groups for the local recurrence risk (p = 0.89). 10-year any recurrence rate was 10.8%. In multivariable analysis with correction for age, pT, pN, resection margins, radiotherapy, year of diagnosis, chemotherapy and hormonal therapy, there was no significant difference between the brachytherapy group and the electron group or the photon group (p = 0.11 and p = 0.28, respectively). The photon group had more recurrences compared to the electron group (Hazard Ratio 1.81, 95% Confidence Interval 1.12; 2.92, p = 0.02).

CONCLUSIONS

The local recurrence risk reduction of the tumour bed boost in breast-conserving therapy is not influenced by the applied boost technique.

Perioperative high-dose-rate interstitial brachytherapy boost for patients with early breast cancer

Aims and background

To evaluate the clinical results of perioperative high-dose-rate interstitial brachytherapy boost treatment preceding whole breast external beam radiation therapy in patients with early breast cancer.

Methods and study design

From 2005–2010, 100 patients with early breast cancer who met the eligibility criteria were enrolled in the study. Brachytherapy implant was performed during the breast-conserving surgery procedure. The boost treatment was started on the 3rd postoperative day to deliver a dose of 15 Gy in 6 fractions over 3 days. Three weeks later, external beam radiation therapy to the whole breast was started for a prescription dose of 50 Gy. The study end points were local recurrence, acute toxicity and cosmetic outcome.

Results

Median age of the patients was 46 years, and median follow-up was 52 months. No patient developed a local recurrence but 5 patients developed distant metastases. The 5-year overall survival and disease-free survival were 86% and 77%, respectively. Eleven patients had acute toxicity; 4 wound complications and 7 grade III skin toxicity. Nine of the 11 patients had breast size of more than 1500 cc. Except for the breast volume (>1500 cc), there was no statistically significant correlation between any of the patient or dosimetry-related factors and acute toxicity. Good-excellent cosmesis was observed in 87% of patients.

Conclusions

Perioperative high-dose-rate interstitial brachytherapy boost followed by whole breast external beam radiation therapy provides excellent local control, acceptable acute toxicity and good-excellent breast cosmesis in patients with early breast cancer.

Pulsed-dose-rate peri-operative brachytherapy as an interstitial boost in organ-sparing treatment of breast cancer

Purpose

To evaluate peri-operative multicatheter interstitial pulsed-dose-rate brachytherapy (PDR-BT) with an intra-operative catheter placement to boost the tumor excision site in breast cancer patients treated conservatively.

Material and methods

Between May 2002 and October 2008, 96 consecutive T1-3N0-2M0 breast cancer patients underwent breast-conserving therapy (BCT) including peri-operative PDR-BT boost, followed by whole breast external beam radiotherapy (WBRT). The BT dose of 15 Gy (1 Gy/pulse/h) was given on the following day after surgery.

Results

No increased bleeding or delayed wound healing related to the implants were observed. The only side effects included one case of temporary peri-operative breast infection and 3 cases of fat necrosis, both early and late. In 11 patients (11.4%), subsequent WBRT was omitted owing to the final pathology findings. These included eight patients who underwent mastectomy due to multiple adverse prognostic pathological features, one case of lobular carcinoma in situ, and two cases with no malignant tumor. With a median follow-up of 12 years (range: 7-14 years), among 85 patients who completed BCT, there was one ipsilateral breast tumor and one locoregional nodal recurrence. Six patients developed distant metastases and one was diagnosed with angiosarcoma within irradiated breast. The actuarial 5- and 10-year disease free survival was 90% (95% CI: 84-96%) and 87% (95% CI: 80-94%), respectively, for the patients with invasive breast cancer, and 91% (95% CI: 84-97%) and 89% (95% CI: 82-96%), respectively, for patients who completed BCT. Good cosmetic outcome by self-assessment was achieved in 58 out of 64 (91%) evaluable patients.

Conclusions

Peri-operative PDR-BT boost with intra-operative tube placement followed by EBRT is feasible and devoid of considerable toxicity, and provides excellent long-term local control. However, this strategy necessitates careful patient selection and histological confirmation of primary diagnosis.

The use of an interstitial boost in the conservative treatment of breast cancer: how to perform it routinely in a radiotherapy department

Purpose

To demonstrate the utility of a boost with interstitial brachytherapy (BT) in breast-conserving therapy (BCT) by doing a thorough review of the literature and describing in detail our technique for delivering this boost.

Material and methods

Our department has been delivering the boost with interstitial BT since 1989, in most cases with rigid needles and a theoretical dosimetry. In the early years, we used low-dose-rate (LDR) with iridium-192 wires. The dose administered was 15 Gy if there were no risk factors for local relapse or 20-25 Gy in the presence of risk factors. The risk factors considered were the presence of a close margin (less than 10 mm) and an extensive intraductal component (more than 25%). After 2002, we switched to high-dose-rate (HDR); using the linear quadratic model we changed the low dose to 3 fractions of 4.5 Gy in the case of no risk factors for local relapse or to 3 fractions of 5 Gy in the presence of risk factors.

Results

In 79 consecutive boost patients treated in our department between 2010 and 2011, with a median follow-up of 46 months, the local control rate was 97.47%. With respect to cosmesis, fibrosis occurred in 17 cases (21.5%) and hyperpigmentation in 26 cases (32.9%). Our hospital's results are comparable in terms of local control and cosmesis to those of other authors.

Conclusions

This educational article describes our department's boost technique with rigid needles and comments briefly on our results using this technique in a group of consecutively treated patients in our department. A review of the literature and the published results on local control and cosmesis is also described.

Tumor bed boost in breast cancer: Brachytherapy versus electron beam

Background:

The prospective study aimed to evaluate the effectiveness of Electron beam or HDR 192Ir Interstitial Implant used as a boost in breast Conservation cases after completion of EBRT. The two therapeutic modalities were compared in terms of the following parameters; i.e. cosmesis, optimization of tumor bed boost, local control, toxicity, and DFS.

Materials and Methods:

The EBRT dose used was 50 Gy in 25 fractions over 5 weeks time. Target delineation of boost treatment was done by CT scan or by high resolution USG. EBRT will be immediately followed by local boost at the primary tumor bearing site of breast with 8 to12 MeV electron beam to a dose of 15 Gy in 6 fractions (Arm A) or with HDR 192Ir interstitial brachytherapy to a dose of 15 Gy in 3 fractions at 6 hours apart (Arm B).

Results:

The excellent cosmesis achieved with electron beam therapy in Arm A was found to be statistically significant (P = 0.025). Local relapse was absent in both the arms. One distant metastasis occurred in Arm A within 10 months of initiation of treatment and one distant metastasis in Arm B came out within 3 months of starting of therapy.

Conclusion:

The study has shown good cosmetic result with electron boost and 100% local control with both the technique. However if there is a more number of patients with longer period of follow up we could have got the actual picture to verify our results and assess long term survival data.

Recurrence of secondary angiosarcoma in a patient with post-radiated breast for breast cancer

INTRODUCTION

Angiosarcoma of the breast is a rare finding. Two different subtypes of angiosarcomas have been described: (a) the Stewart-Treves syndrome and (b) the cutaneous post-radiation angiosarcoma. We report a case where both types of angiosarcoma occurred.

CASE REPORT

At first, an angiosarcoma affecting parenchyma of the breast was observed after radiotherapy following breast conserving therapy and a history of lymphoedema of the radiated area. Additionally, a subsequent local recurrence of the angiosarcoma of the skin after mastectomy and complete resection of the primary angiosarcoma was diagnosed.

DISCUSSION

This case is distinguished by a short latency period after primary therapy (less than 4 years) and a rapid recurrence after complete resection (14 weeks). Patients should be pointed to this possible complication of radiotherapy and transferred to seek medical advice immediately in case of skin lesion in the irradiated area: even many years after radiotherapy. Additionally, every oncologist should be aware of this rare complication as quick diagnosis and prompt surgical treatment is indispensable due to the aggressive entity of angiosarcoma.

Breast-Conservative Surgery With Close or Positive Margins: Can the Breast Be Preserved With High-Dose-Rate Brachytherapy Boost?

PURPOSE

To evaluate the likelihood of preserving the breast in women who show close or positive margins after conservative surgery for early breast carcinoma.

METHODS AND MATERIALS

Since 1996, 125 women with less than 5 mm or positive margins and positive separate cavity margin sampling were entered in a prospective trial with high-dose radiotherapy. A standard dose of 50 Gy to the whole breast was followed by a high-dose-rate brachytherapy application delivering 3 fractions of 4.4 Gy in 24 hours. The median follow-up was 84 months.

RESULTS

There were only seven local recurrences, with an actuarial local control rate of 95.8% at 5 years and 91.1% at 9 years. Actuarial overall and cause-specific survival rates were 92.6% and 95% at 5 years and 86.7% and 90.4% at 9 years, respectively. Late fibrosis was the most common complication, in 30% of patients, with good or excellent cosmetic results in 77%. The final result was that 95.2% of breasts were preserved.

CONCLUSIONS

Close or positive-margin breast cancer can be well managed with a high-dose boost in a wide tumor bed by means of high-dose-rate brachytherapy. This technique can avoid mastectomy or poor cosmetic resection, with minimal risk of local or general failure.

Integrating Partial Breast Irradiation into Surgical Practice and Clinical Trials

The use of accelerated partial breast irradiation (APBI) in place of whole-breast irradiation (WBI) for breast-conservation therapy (BCT) is an area of intensive clinical investigation. This article describes evolving methods of APBI in comparison to WBI and in the setting of ongoing clinical trials.

Placing the boost in breast-conservation radiotherapy: A review of the role, indications and techniques for breast-boost radiotherapy

Randomised trials have established that the addition of a boost dose of radiotherapy to the lumpectomy site after whole-breast adjuvant radiotherapy further improves local control achieved by whole-breast radiotherapy alone. The absolute size of this benefit varies according to the baseline risk of local recurrence. Age is the strongest predictor of benefit. Below the age of 40 years, the absolute benefit of a boost seems to be substantial, and there are no clearly identified groups unlikely to benefit. Above the age of 50 years, the benefit is small, and several additional risk factors for local failure would need to be present to merit boost treatment. These may include tumour size, high grade, high mitotic rate, lymphovascular invasion, extensive and high grade associated with intraduct carcinoma, receptor-positive tumours when avoidance of anti-oestrogen therapy is desired or receptor-negative tumours. Other independent reasonable indications for the use of a boost would be positive margins where further surgery is not indicated. If a boost is indicated, a variety of techniques may be used and toxicity and cosmetic results remain highly acceptable. Overall, there seems to be no substantial differences in boost technique results; however, interstitial techniques may have advantages for deeper targets compared with electrons. Irrespective of technique, accurate localisation will maximise the benefit of a boost. Surgical clips are strongly recommended to facilitate localisation.

Sobreimpresión en fracción única con braquiterapia intersticial de alta tasa en el tratamiento conservador del carcinoma de mama

INTRODUCTION

We evaluated the effectiveness of interstitial high dose rate brachytherapy as a single fraction boost to the surgical bed in patients with breast cancer undergoing conservative treatment. The comparison was with the alternative of electron boost.

MATERIALS AND METHODS

Between April 1999 and December 2000, we conducted a prospective study of 84 patients with infiltrative breast carcinoma treated with conservative surgery, with free margins. This was followed by external radiotherapy to the breast of up to 46 Gy and one application of brachytherapy with needles inserted into the surgical bed, and administering 7 Gy to 90% with high dose rate (HDR).

RESULTS

With a mean follow-up of 43 months, only one patient had therapeutic failure in the implant area, and local control was 98.5%. Another patient had a 2nd tumour in a different quadrant and 3 developed metastasis. Survival at 5 years was 98.7%. Acute toxicity was minimal, with excellent or good cosmetic appearance in 95%.

CONCLUSIONS

Brachytherapy with high dose rate as single fraction boost in conservative treatment of breast carcinoma is simple, fast, well tolerated, with excellent local control, good cosmetic appearance, and with minimal late-onset toxicity.

Predictors of local recurrence after breast-conservation therapy

Breast-conserving therapy (BCT) is a proven local treatment option for select patients with early-stage breast cancer. This paper reviews pathologic, clinical, and treatment-related features that have been identified as known or potential predictors for ipsilateral breast tumor recurrence in patients treated with BCT. Pathologic risk factors such as the final pathologic margin status of the excised specimen after BCT, the extent of margin involvement, the interaction of margin status with other adverse features, the role of biomarkers, and the presence of an extensive intraductal component or lobular carcinoma in situ all impact the likelihood of ipsilateral breast tumor recurrence. Predictors of positive repeat excision findings after conservative surgery include young age, presence of an extensive intraductal component, and close or positive margins in prior excision. Finally, treatment-related factors predicting ipsilateral breast tumor recurrence include extent of breast radiation therapy, use of a boost to the lumpectomy cavity, use of tamoxifen or chemotherapeutic agents, and timing of systemic therapy with irradiation. The ability to predict for an increased risk of ipsilateral breast tumor recurrence enhances the ability to select optimal local treatment strategies for women considering BCT.

CT computer-optimized high-dose-rate brachytherapy with surface applicator technique for scar boost radiation after breast reconstruction surgery

PURPOSE

Immediate breast reconstruction has become increasingly prevalent after mastectomy for breast cancer. Postoperative scar boost radiation for the reconstructed breast presents many planning challenges due to the shape, size, and curvature of the scar. High-dose-rate (HDR) surface applicator brachytherapy is a novel and effective method of delivering scar boost radiation. Two cases, one with a saline implant and one with a transverse rectus abdominis musculocutaneous flap reconstruction, illustrate the method and advantages of HDR optimization of surface applicators.

METHODS AND MATERIALS

For 2 patients a mold of the breast was made with Aquaplast sheets. A reproducible system was used for arm positioning. Skin fiducials, including tattoos from external beam planning, were matched to fiducials on the mold. HDR catheters were sited on the mold at 1cm intervals, with the central catheter situated along the scar. Topographically, both scars demonstrated extreme curvature in both craniocaudal and mediolateral directions. A CT computer-optimized HDR plan was developed, with the reference dose prescribed at the skin surface. The dosimetry was compared to single-field and matched-field electron plans.

RESULTS

This surface applicator technique provided a uniform skin dose of 100% to the entire clinical target volume (CTV) without hot spots in both patients. The patient position and surface applicator setup were consistently reproducible. The patients tolerated the treatment well with minimal skin erythema. In the single-field electron plan, skin dose was decreased to 50% at the periphery of the scar. Matching fields addressed this depth dose decrement, but resulted in large localized hot spots of more than 200% centrally in each field.

CONCLUSION

CT computer-optimized HDR surface applicator brachytherapy provided a reproducible homogeneous method of treating highly curved scars on the reconstructed breast. Electron beam treatment would result in longer and more complex treatments yet still provide a less homogeneous dose than this surface applicator technique.

Forward-planned, multiple-segment, tangential fields with concomitant boost in the treatment of breast cancer

We report on the utility of forward-planned, 3-dimensional (3D), multiple-segment tangential fields for radiation treatment of patients with breast cancer. The technique accurately targets breast tissue and the tumor bed and reduces dose inhomogeneity in the target. By decreasing excess dose to the skin and lung, a concomitant boost to the tumor bed can be delivered during the initial treatment, thereby decreasing the overall treatment time by one week. More than 120 breast cancer patients have been treated with this breast conservation technique in our clinic. For each patient, a 3D treatment plan based upon breast and tumor bed volumes delineated on computed tomography (CT) was developed. Segmented tangent fields were iteratively created to reduce "hot spots" produced by traditional tangents. The tumor bed received a concomitant boost with additional conformal photon beams. The final tumor bed boost was delivered either with conformal photon beams or conventional electron beams. All patients received 45 Gy to the breast target, plus an additional 5 Gy to the surgical excision site, bringing the total dose to 50 Gy to the boost target volume in 25 fractions. The final boost to the excision site brought the total target dose to 60 Gy. With minimum follow-up of 4 months and median follow-up of 11 months, all patients have excellent cosmetic results. There has been minimal breast edema and minimal skin changes. There have been no local relapses to date. Forward planning of multi-segment fields is facilitated with 3D planning and multileaf collimation. The treatment technique offers improvement in target dose homogeneity and the ability to confidently concomitantly boost the excision site. The technique also offers the advantage for physics and therapy staff to develop familiarity with multiple segment fields, as a precursor to intensity-modulated radiation therapy (IMRT) techniques.

The influence of the boost technique on local control in breast conserving treatment in the EORTC 'boost versus no boost' randomised trial

BACKGROUND AND PURPOSE

The EORTC Trial 22881/10882 investigating the role of a boost dose in breast conserving therapy demonstrated a significantly better local control rate with the higher radiotherapy dose, especially in women younger than 50 years of age. This paper investigates the potential impact of the different boost techniques on local control and on fibrosis after breast conserving therapy.

PATIENTS AND METHODS

From 1989 to 1996, 2661 patients were randomised to receive a boost dose of 16Gy to the primary tumour bed after microscopically complete tumorectomy and 50Gy whole breast irradiation. The choice of the boost technique was left to the treating investigator. Treatment data were prospectively recorded as well as the clinical outcome in terms of local control and fibrosis. Sixty-three percent of the patients received a boost dose with fast electrons, 28% with photon beams and 9% with interstitial brachytherapy.

RESULTS

At 5 years, local recurrences were seen in 74 of the 1635 patients who received an electron boost (4.8%, CI 3.6-5.9%), in 28 of the 753 patients who received a photon boost (4.0%, CI 3.4-5.5%) and in 6 of the 225 patients after an interstitial boost (2.5%, CI 0.3-4.6%). The grade of fibrosis in the whole breast as well as at the primary tumour bed, as scored by the treating radiation oncologist, was similar in the three groups.

CONCLUSIONS

Although the three groups are of a rather unequal size, the results of the interstitial boost seem similar in terms of fibrosis and at least as good in terms of local control, despite a lower treatment volume and a longer overall treatment time.

[Brachytherapy boost for breast cancer: what do we know? Where do we go?]

Since many years, Brachytherapy (BT) appears to play an important role in the treatment of many solid tumors. For breast cancer, BT is usually used as boost after postoperative external beam radiation therapy. In certain circumstances, BT can be used as sole radiation technique focalized on the tumor bed or more rarely, as second conservative treatment in case of local recurrence for woman refusing salvage mastectomy. Boost BT is most often applied via an interstitial technique while the dose rate can vary from low to high dose rate through pulse dose rate. All of those boost techniques were published and some of them compared the results obtained with BT and external beam electron therapy. The analysis of the published phase II and III trials was not able to show significant differences between the two boost techniques in term of local control as well as late skin side effects. However, we noted that the patients who received BT boost presented a higher risk of local recurrence compare to those treated with electron therapy, due to age, margin status or presence of extensive intraductal component. Only a phase III trial randomizing BT boost vs electron therapy boost could show a possible improvement of local control rate in the BT arm; however, this trial should enroll patients with a real high risk of local recurrence in order to take benefit from the dosimetric advantages of BT.

Breast-conserving therapy in young women with invasive carcinoma of the breast

Higher local recurrence rates have been reported in young women with invasive carcinoma of the breast treated with breast-conserving therapy (BCT). However, age itself may not be responsible for this increased risk of recurrence. To investigate this further, a computerized literature search of MEDLINE was performed using data from 1996 to May 2003. The research was limited to female patients with localized, invasive adenocarcinoma of the breast but also included patients of young age with ductal carcinoma in situ. Women of young age with breast cancer, treated with BCT are at an increased risk of recurrence ranging from 7.5 to 35%. However, the data would suggest that the increased risk is secondary to the association of young age with more aggressive tumours and a positive family history of breast cancer. Other factors that may explain the adverse prognosis in women of a young age include associated genetic abnormalities and the lack of mammographic screening programmes for women of young age. Young age is a risk factor for breast recurrence after BCT. However, management decisions should be based on tumour stage, grade and other related prognostic features rather than on young age alone.

Accuracy of ultrasound in localization of breast boost field

BACKGROUND AND PURPOSE

To prospectively compare diagnostic ultrasound to the 'gold standard' of surgical clips for localization of the lumpectomy site for electron boost irradiation.

PATIENTS AND METHODS

Consecutive breast cancer patients referred following lumpectomy underwent diagnostic ultrasound in radiation treatment position 21-100 days post-surgery. All patients had 3-6 surgical clips defining the excision cavity. The site was marked on the skin and depth was measured. Target depth was the deepest aspect of the cavity plus a 1 cm deep margin. Treatment fields were prescribed with a 2 cm margin on the cavity, and electron energy was chosen to cover the target depth. Surgical clip position was assessed on orthogonal simulator films.

RESULTS

Localizations were performed in 54 breasts (52 women). The mean interval post-surgery was 53 (SD 17) days. Overall, 35/54 (65%) of localizations were adequate, 15/54 (28%) were marginal and 4/54 (7%) were inadequate. Regression showed that lower patient weight (r=-0.37, P=0.006) predicted adequacy of localization, with better accuracy in lighter women.

CONCLUSIONS

The accuracy rate for ultrasound exceeds the 20-50% reported for clinical localization. Diagnostic ultrasound may be used to improve the accuracy when surgical clips are not present.

Changes in management techniques and patterns of disease recurrence over time in patients with breast carcinoma treated with breast-conserving therapy at a single institution

BACKGROUND

The authors reviewed changes in the initial clinical presentation, management techniques, and patterns of disease recurrence over time (1981-1996) in patients with breast carcinoma treated with breast-conserving therapy (BCT) at a single institution. The goals of the current study were to determine the frequency and use of optimal local and systemic therapy techniques and to evaluate the impact of these changes on treatment efficacy.

METHODS

Six hundred seven patients with American Joint Committee on Cancer Stage I or II invasive breast carcinomas treated with BCT at William Beaumont Hospital (Royal Oak, MI) constituted the study population. All patients received at least an excisional biopsy of the primary tumor, an axillary lymph node staging procedure, and postoperative radiotherapy (RT) (a median tumor bed dose of 61 Gray [Gy] was administered). All sides were reviewed by one pathologist. Numerous clinicopathologic and treatment-related factors were analyzed to monitor changes that occurred over time. Changes in patterns of disease recurrence and treatment efficacy over time also were analyzed.

RESULTS

Over the time period analyzed, changes at initial presentation included an increase in the mean age at diagnosis (age 56.1 years vs. 61.4 years; P < 0.001), a decrease in the number of patients with clinically palpable tumors (78% vs. 36%; P < 0.001), a decrease in the mean tumor size (2.2 cm vs. 1.6 cm; P < 0.001), but no change in the percentage of patients with negative lymph nodes (79% vs. 78%; P = 0.83). No differences over time were observed in mean tumor grade (2.0 vs. 1.9; P = 0.2) or the presence of angiolymphatic invasion (27% vs. 26%; P = 0.25). Changes in surgical management and pathologic assessment included the more frequent use of reexcision (46% vs. 81%; P < 0.001), larger mean total volumes of breast tissue specimens excised (115 cm3 vs. 189 cm3; P = 0.001), a larger percentage of patients with final negative surgical margins (74% vs. 97%; P < 0.001), and a small increase in the mean number of lymph nodes excised (13.8 lymph nodes vs. 14.1 lymph nodes; P = 0.01). The only other significant change in the pathologic management of patients over time included a doubling in the mean number of slides examined (10.6 slides vs. 21.1 slides; P < 0.001). Changes in adjuvant local and systemic therapy included an increase in the percentage of patients treated with > 60 Gy to the tumor bed (66% vs. 95%; P < 0.001), a doubling in the mean number of days from the last surgery to the start of RT (24 days vs. 50 days; P < 0.001), and a decrease in the use of regional lymph node RT (24% vs. 8%; P < 0.001). The use of adjuvant tamoxifen increased from 10% to 61% (P < 0.001). Finally, improvements were observed in the 5-year and 12-year actuarial rates of local disease recurrence (8% vs. 1% and 21% vs. 9%, respectively; P = 0.001) and distant metastases (12% vs. 4% and 22% vs. 9%, respectively; P = 0.006). No changes in the mean number of years to ipsilateral (6.5 years vs. 6.4 years; P = 0.59) or distant disease recurrence (4.6 years vs. 3.8 years; P = 0.73) were observed.

CONCLUSIONS

The impact of screening mammography and substantial changes in surgical, pathologic, RT, and systemic therapy recommendations were observed over time in the study population. These changes were associated with improvements in 5-year and 12-year local and distant control rates and suggested that improvements in outcome can be realized through adherence to best practice guidelines and continuous monitoring of treatment outcome data.

Analysis of a large number of clinical studies for breast cancer radiotherapy: estimation of radiobiological parameters for treatment planning

Numerous studies of early-stage breast cancer treated with breast conserving surgery (BCS) and radiotherapy (RT) have been published in recent years. Both external beam radiotherapy (EBRT) and/or brachytherapy (BT) with different fractionation schemes are currently used. The present RT practice is largely based on empirical experience and it lacks a reliable modelling tool to compare different RT modalities or to design new treatment strategies. The purpose of this work is to derive a plausible set of radiobiological parameters that can be used for RT treatment planning. The derivation is based on existing clinical data and is consistent with the analysis of a large number of published clinical studies on early-stage breast cancer. A large number of published clinical studies on the treatment of early breast cancer with BCS plus RT (including whole breast EBRT with or without a boost to the tumour bed, whole breast EBRT alone, brachytherapy alone) and RT alone are compiled and analysed. The linear quadratic (LQ) model is used in the analysis. Three of these clinical studies are selected to derive a plausible set of LQ parameters. The potential doubling time is set a priori in the derivation according to in vitro measurements from the literature. The impact of considering lower or higher T(pot) is investigated. The effects of inhomogeneous dose distributions are considered using clinically representative dose volume histograms. The derived LQ parameters are used to compare a large number of clinical studies using different regimes (e.g., RT modality and/or different fractionation schemes with different prescribed dose) in order to validate their applicability. The values of the equivalent uniform dose (EUD) and biologically effective dose (BED) are used as a common metric to compare the biological effectiveness of each treatment regime. We have obtained a plausible set of radiobiological parameters for breast cancer: alpha = 0.3 Gy(-1), alpha/beta = 10 Gy and sub-lethal damage repair time T(rep) = 1 h (mono-exponential behaviour is assumed). This set of parameters is consistent with in vitro experiments and with previously reported analyses. Using this set of parameters, we have found that most of the studies, using BCS plus whole breast RT and a boost to the tumour bed, have EUDs ranging from 60-70 Gy. No correlation is found between BED and the local recurrence rate. The treatments of BCS plus brachytherapy alone have a wide range of EUD (30-50 Gy), which is significantly lower than the treatments with whole breast EBRT plus a boost of the tumour bed. The studies with different fractionation schemes for whole breast EBRT also show a significant variation of EUD. Carefully designed clinical studies with large numbers of patients are required to determine clinically the relative effectiveness of these treatment variations. The derived LQ parameter set based on clinical data is consistent with in vitro experiments and previous studies. As demonstrated in the present work, these radiobiological parameters can be potentially useful in radiotherapy treatment planning for early breast cancer, e.g., in comparing biological effectiveness of different radiotherapy modalities, different fractionation schemes and in designing new treatment strategies.

Dose-volume analysis of radiotherapy for T1N0 invasive breast cancer treated by local excision and partial breast irradiation by low-dose-rate interstitial implant

PURPOSE

To evaluate the toxicity of partial breast irradiation (RT) using escalating doses of low-dose-rate interstitial implant as the sole adjuvant local therapy for selected T1N0 breast cancer patients treated by wide local excision. The results of a European Organization for Research and Treatment of Cancer study have demonstrated a significant local control benefit using external beam RT to 65 Gy compared with 50 Gy. Thus, the tolerance of escalating doses of partial breast RT should be determined, because this approach may become a standard treatment for patients with early-stage breast cancer.

METHODS AND MATERIALS

Between 1997 and 2001, 48 patients with T1N0M0 breast cancer were enrolled into an institutional review board-approved Phase I/II protocol using low-dose-rate brachytherapy implants after wide local excision and lymph node staging surgery. Brachytherapy was started 3-4 days after surgery at a dose rate of 50 cGy/h, using (192)Ir sources evenly spaced to cover 3 cm around the resection margins. Typically, 2-3 planes were used, with a median of 14 catheters (range 10-16). The total dose was escalated in three groups: 50 Gy (n = 19), 55 Gy (n = 16), and 60 Gy (n = 13). The implant volume was calculated and used to classify patients into quartiles: 76-127 cm(3) (n = 12), 128-164 cm(3) (n = 12), 165-204 cm(3) (n = 12), and >204 cm(3) (n = 12). Cosmesis, patient satisfaction, treatment-related complications, mammographic abnormalities, rebiopsies, and disease status were recorded at each scheduled patient visit.

RESULTS

The median follow-up for all patients was 23.1 months (range 2-43). Very good to excellent cosmetic results were observed in 91.8% of patients. Ninety-two percent of patients were satisfied with their cosmetic outcome and said they would choose brachytherapy again over the standard course of external beam RT. Six perioperative complications occurred: two developed bleeding at the time of catheter removal, two had abscesses, one developed a hematoma, and one had a nonhealing sinus tract requiring surgical intervention. Significant fibrosis (moderate-to-severe scarring and thickening of the skin and breast) was noted in only 4 patients; 1 had received 55 Gy and 3 had received 60 Gy. Abnormal posttreatment mammograms were seen in 19 patients. Eight patients underwent rebiopsy for abnormalities found either by mammography or on physical examination; all proved to be fat necrosis or post-RT changes. The rebiopsy rates appeared to correlate with doses >/=55 Gy (6 [75%] of 8 compared with 29 [60%]of 48 overall) and implant volumes >/=128 cm(3) (7 [87.5%] of 8 compared with 36 [75%] of 48 overall). To date, no local, regional, or distant recurrences have been observed.

CONCLUSION

Low-dose-rate implants up to 60 Gy were well-tolerated overall. With an implant dose of 60 Gy, the incidence of posttreatment fibrosis (25%) appeared to be increased. Only the long-term follow-up of this and other implant studies will allow an understanding of the total radiation dose necessary for tumor control and the volume of breast that requires treatment.

Does local recurrence affect the rate of distant metastases and survival in patients with early-stage breast carcinoma treated with breast-conserving therapy?

BACKGROUND

The purpose of the current analysis was to evaluate the impact of local recurrence (LR) on the development of distant metastases (DM), overall survival (OS), and cause specific survival (CSS) in patients with early-stage breast carcinoma who underwent conservative surgery (CS) and received postoperative radiotherapy (RT).

METHODS

Between 1980 and 1995, 1169 patients underwent CS and received RT. All patients were followed for > 1 year and had < or = 4 lymph nodes involved with disease. The median duration of follow-up was 7.7 years. A Cox proportional hazards model was performed to evaluate the effect of LR on the development of DM and CSS. A matched-pair analysis that controlled for multiple prognostic factors also was performed comparing the outcomes of patients with and without LR.

RESULTS

The LR rate was 11% at 12 years. For the entire population, LR led to poorer OS and CSS rates at 12 years compared with local control (LC) (71% vs. 81% [P = 0.001] and 69% vs. 88% [P < 0.001], respectively). In a Cox multiple regression model, LR was a significant predictor of disease specific mortality. The hazard ratio (HR) associated with LR was 2.69 for mortality and 2.67 for DM (P < 0.001 and P < 0.001, respectively). The median time from surgery to the development of DM was 3.8 years for patients without LR compared with 4.7 years for patients with LR. Patients who developed LR also had two peaks in the rate of DM (at 2.5 years and at 6.5 years) compared to only one peak (at 1.5 years) for patients who did not develop LR. The impact of LR on DM still was evident in patients with small tumors (< or = 2.0 cm; P < 0.001), negative lymph nodes (P = 0.004), or both (P < 0.001). Recurrent disease that developed outside of the surgical bed region had no negative effect on survival. In the matched-pair analysis (controlling for age, tumor size, grade, number of positive lymph nodes, and estrogen receptor status), LR remained the most significant predictor of mortality (HR: mortality, 5.86; DM, 6.43).

CONCLUSIONS

The current results suggest that LR may be responsible for an increase in DM and disease specific mortality in patients who undergo CS and receive RT. This suggestion is reinforced by the distinct difference seen in the time distribution of DM after LR developed and by the fact that recurrent disease that originated outside of the surgical bed did not affect OS. These data reinforce the necessity to insure optimal LC in patients who are treated with breast-conserving therapy.

The role of boost irradiation in the conservative treatment of stage I-II breast cancer

In this article, we review the current status, indication, technical aspects, controversies, and future prospects of boost irradiation after breast conserving surgery (BCS). BCS and radiotherapy (RT) of the conserved breast became widely accepted in the last decades for the treatment of early invasive breast cancer. The standard technique of RT after breast conservation is to treat the whole breast up to a total dose of 45 to 50 Gy. However, there is no consensus among radiation oncologists about the necessity of boost dose to the tumor bed. Generally accepted criteria for identification of high risk subgroups, in which boost is recommended, have not been established yet. Further controversy exists regarding the optimal boost technique (electron vs. brachytherapy), and their impact on local tumor control and cosmesis. Based on the results of numerous retrospective and recently published prospective trials, the European brachytherapy society (GEC-ESTRO), as well as the American Brachytherapy Society has issued their guidelines in these topics. These guidelines will help clinicians in their medical decisions. Some aspects of boost irradiation still remain somewhat controversial. The final results of prospective boost trials with longer follow-up, involving analyses based on pathologically defined subgroups, will clarify these controversies. Preliminary results with recently developed boost techniques (intraoperative RT, CT-image based 3D conformal brachytherapy, and 3D virtual brachytherapy) are promising. However, more experience and longer follow-up are required to define whether these methods might improve local tumor control for breast cancer patients treated with conservative surgery and RT.

The emerging role of brachytherapy in the management of patients with breast cancer

Brachytherapy remains an important treatment option in the overall management of patients with breast cancer. In patients treated with breast conserving therapy (BCT), prospective randomized trials have established the advantage of a boost in most patients. Interstitial brachytherapy has consistently been shown to provide an important option to boost patients, and in certain clinical settings it may provide a more appropriate means of dose delivery. The concept of delivering partial breast irradiation with accelerated treatment schedules has now provided brachytherapy a new and exciting role in the management of patients treated with BCT. There are now data available from several phase I/II studies suggesting that brachytherapy alone can be used safely and reproducibly in this setting in order to reduce the time, inconvenience, and toxicity associated with traditional radiation therapy. Although preliminary results with brachytherapy alone are encouraging, proper patient selection and optimal dosimetric guidelines must be employed in order to achieve success when used in this setting.