Prospective Clinical Trial of Premastectomy Radiotherapy Followed by Immediate Breast Reconstruction for Operable Breast Cancer

PURPOSE/OBJECTIVE(S)

Radiation delivered prior to mastectomy and autologous breast reconstruction may avoid the adverse effects of radiation on autologous donor tissue while providing the psychologic benefit of immediate reconstruction. We aimed to study the feasibility of premastectomy radiation therapy (PreMRT).

MATERIALS/METHODS

A total of 50 women enrolled in a prospective trial of preoperative radiation to the breast and regional nodes followed by mastectomy with axillary evaluation and immediate breast reconstruction. The trial was embedded in a randomized trial of hypofractionated versus conventionally fractionated regional nodal irradiation (NCT02912312). Eligible women enrolled from 2018-22, had cT0-T3 N0-3 breast cancer, and a pre-operative recommendation for radiation. The primary outcome was frequency of complete free flap loss. Mastectomy skin flap necrosis was assessed by validated SKIN grading score. The Satisfaction with Breast Cosmetic Outcomes Scales evaluated patient satisfaction with cosmetic result. Descriptive statistics and 95% exact confidence intervals were calculated.

RESULTS

One patient withdrew prior to any treatment and one elected not to have breast reconstruction. Median age of the 48 women completing PreMRT and reconstruction was 48 [range 31-72]. Most had ER-positive HER2-negative (77%), cT3 (54%) or cT2 (38%), cN1 (79%) disease and received 50 Gy in 25 fractions (n = 24) or 40.05 Gy in 15 fractions (n = 23). Four received 10-16 Gy internal mammary or infraclavicular boost. 35% VMAT, 48% matched photon-electron, and 17% partially-wide-tangent technique. Median time to surgery was 23 days [14-85]. Skin reaction delayed surgery for one patient. Most had skin-sparing mastectomy (92%) and axillary lymph node dissection (67%). 12 surgeons performed the reconstructions: 35 deep inferior epigastric perforators; 4 profunda artery perforator; 2 muscle-sparing transverse rectus abdominis myocutaneous; 1 latissimus dorsi (LD); 2 LD/implant; 2 LD/tissue expander (TE); and 2 subpectoral (SP) TE. There were no complete flap losses. Two patients (4.4%, 95% CI 0.5%-14.8%) with free flaps had partial flap loss with revision surgery. Both patients with SP TEs had infections and unplanned reoperation. The protocol was subsequently amended to not allow SP TE reconstruction. Eight patients had skin flap necrosis: 5 partial and 3 full thickness necrosis; only 1 required operative debridement. Seven had pathologic complete response. At six months 19/31 (61%) reported being "quite a bit" or "very much" satisfied with how they looked in the mirror clothed. There are no recurrences with a median follow up of 33 months [5-119].

CONCLUSION

Radiation treatment of the breast and lymph node basins prior to mastectomy with immediate autologous reconstruction is feasible. There were no autologous flap loses and complication rates are similar to reconstruction after radiation series. This promising strategy reduces time to autologous reconstruction and merits further prospective study.

Abstract GS4-04: Primary results of NSABP B-39/RTOG 0413 (NRG Oncology): A randomized phase III study of conventional whole breast irradiation (WBI) versus partial breast irradiation (PBI) for women with stage 0, I, or II breast cancer

Background: Conventional WBI after lumpectomy for early-stage breast cancer decreases ipsilateral breast tumor recurrence (IBTR), yielding comparable results to mastectomy. Accelerated PBI appears effective in reducing IBTR by treating only the tumor bed area. As the majority of IBTR occur at or in the vicinity of the tumor bed, we hypothesized that PBI would be as effective as WBI in controlling IBTR. The primary aim of NSABP B-39/RTOG 0413 was to determine if PBI provides equivalent local tumor control post lumpectomy compared to WBI in pts with early-stage breast cancer. The equivalency test was based on a 50% margin of increase in the hazard ratio (HR=1.5). Secondary endpoints included: overall survival (OS), recurrence-free interval (RFI), distant disease-free interval (DDFI), and toxicity.

Methods: Eligible pts had lumpectomy with histologically-free margins and 0-3 positive axillary nodes. Pts were stratified by stage, menopausal status, hormone receptor status, and intent to receive chemotherapy and then randomized to PBI or WBI. PBI was 10 fractions of 3.4-3.85 Gy, given twice daily with either brachytherapy or 3D external beam radiation. WBI was 50 Gy in 2 Gy fractions given daily with a sequential boost to the surgical cavity. Follow-up was every 6 mos for 5 yrs and then annually. All analyses were by intent-to-treat.

Results: From 3-21-05 to 4-16-13, 4216 pts were randomized: 2107 PBI; 2109 WBI. 61% were postmenopausal; 81% were hormone receptor-positive; 29% intended to receive chemotherapy. Stage distribution was: DCIS, 24%; invasive pN0, 65%; invasive pN1, 10%. As of 7-31-18, median follow-up was 10.2 yrs. There were 161 IBTRs as first events: 90 PBI v 71 WBI (HR 1.22; 90%CI 0.94-1.58). Per protocol-defined margin, to declare PBI and WBI equivalent regarding IBTR risk, the 90% CI for the observed HR had to lie entirely between 0.667 and 1.5. The percent of pts IBTR-free at 10 yrs was 95.2% PBI v 95.9% WBI. A statistically significant difference in the 10-yr RFI rate favored WBI (91.9% PBI v 93.4% WBI; HR 1.32; 95%CI 1.04-1.68; p=0.02). No statistically significant differences existed between PBI and WBI in DDFI (HR 1.31; 95%CI 0.91-1.91; p=0.15), OS (HR 1.10; 95%CI 0.90-1.35; p=0.35), or DFS (HR 1.12; 95%CI 0.98-1.29; p=0.11). Grade 3 toxicity was 9.6% PBI v 7.1% WBI, and grade 4-5 toxicity was 0.5% v 0.3%, respectively.

Discussion: PBI did not meet the criteria for equivalence to WBI in controlling IBTR based on the upper limit of the hazard ratio confidence interval. However, the absolute difference in 10-yr rate of IBTR was <1% (4.8% PBI v 4.1% WBI). The risk of an RFI event was statistically significantly higher for PBI compared to WBI, but the absolute difference in 10-yr RFI rate was also small (8.1% PBI v 6.6% WBI). DDFI, OS, and DFS were not statistically different for PBI v WBI. Grade 3-5 toxicities, although low, were more common for PBI than WBI. The trial population was heterogeneous, ranging from Stage 0-2 breast cancer, and outcome by risk categories are being analyzed.

Support: U10CA180868, -180822, UG1CA189867.

Citation Format: Vicini FA, Cecchini RS, White JR, Julian TB, Arthur DW, Rabinovitch RA, Kuske RR, Parda DS, Ganz PA, Scheier MF, Winter KA, Paik S, Kuerer HM, Vallow LA, Pierce LJ, Mamounas EP, Costantino JP, Bear HD, Germaine I, Gustafson G, Grossheim L, Petersen IA, Hudes RS, Curran, Jr. WJ, Wolmark N. Primary results of NSABP B-39/RTOG 0413 (NRG Oncology): A randomized phase III study of conventional whole breast irradiation (WBI) versus partial breast irradiation (PBI) for women with stage 0, I, or II breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS4-04.

Abstract PD3-07: A phase II pre-surgical trial of lapatinib for the treatment of women with HER2 positive or EGFR positive ductal carcinoma in situ

Background: Estrogen receptor (ER)-negative tumors and human epidermal growth factor 2-Neu (HER2) positive breast cancers are known to be more clinically aggressive subtypes of breast cancer and account for 30% of all breast cancers. Women with HER2 + breast cancers, whether ER+ or ER -, require cytotoxic chemotherapy with a HER2-targeting agent, and often have adverse outcomes. Thus, preventive agents are needed to reduce the incidence of these subtypes of aggressive breast cancer. Lapatinib, a dual tyrosine kinase inhibitor, inhibits epidermal growth factor receptors (EGFR) and HER2 kinases and has shown to decrease breast cell proliferation in invasive breast cancer and adjacent premalignant lesions. Therefore, we conducted a multi-institutional randomized Phase II clinical trial to study the effects of the signal transduction inhibitor lapatinib in women with HER2-positive or EGFR-positive ductal carcinoma in situ (DCIS).

Methods: Randomized participants received either lapatinib (750mg, 1000mg, or 1500mg) or placebo daily for 2-6 weeks prior to their surgery. After minimal accrual, the trial was later amended to lapatinib 1000mg or placebo. Pre-treatment breast tissue was obtained from initial diagnostic core biopsy and post-treatment breast tissue was obtained from surgical excision specimen. Blood was obtained prior to surgery to assess serum lapatinib level. Participants kept a daily symptom assessment log and had a cardiac assessment at baseline and prior to surgery. Patients were instructed to take drug up to and including the day before surgery. The dual primary endpoint for this study was change in proliferation in pre- versus post-treatment biopsies between the two treatment arms, as measured by Ki67 as well as toxicity assessment. Secondary endpoints included incidence of DCIS at surgery and modulation of tissue biomarker expression in growth factor receptors (EGFR, ErbB2); phosphorylated growth factor receptor (phospho-ErbB2); signal transduction markers (MAPK, phospho-MAPK); hormone receptors (ER, PR); and p27.

Results:Twenty-two women (mean age: 51; range: 32-66) with HER2+ or EGFR+ DCIS were treated with lapatinib (1,000 or 1,500 mg) or placebo for 2–6 weeks prior to surgical excision. Ki67 expression was significantly decreased in the lapatinib treatment arms compared to placebo (p=0.0122). Diarrhea, fatigue, and skin reactions were notable adverse events that occurred predominately in the lapatinib arm compared to placebo. No grade 3 or 4 events related to the study drug were noted during the study. No changes were noted in cardiac function. DCIS was present in all surgical specimens in both arms. Invasive breast cancer was noted in 1 patient on lapatinib 1000mg and 3 patients on placebo. No statistically significant changes were noted in signal transduction biomarkers

Conclusion:These results demonstrate the effectiveness of lapatinib in reducing proliferation in women with EGFR+ or HER2+ DCIS. Even low-grade toxicities can deter use of an agent in the prevention setting. This and the lack of a risk model for HER2+ and triple negative breast cancer make the development of larger scale clinical prevention trials of lapatinib for the prevention a challenge.

Citation Format: Thomas PS, Contreras A, Pruthi S, Krontiras H, Rimawi M, Garber J, Wang T, Hilsenbeck SG, Vornik LA, Gilmer T, Friedman R, Heckman-Stoddard BM, Dunn B, Kuerer H, Brown PH. A phase II pre-surgical trial of lapatinib for the treatment of women with HER2 positive or EGFR positive ductal carcinoma in situ [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD3-07.

Abstract P3-01-05: Circulating tumor cell detection predicts early recurrence in patients with non-metastatic breast cancer

Background:

Our group and others have shown that CTCs are identified in 20-25% of non-metastatic breast cancer patients. Recent data suggests that circulating tumor cell (CTC) detection at 5 years follow-up predicts late recurrence for non-metastatic, estrogen receptor positive, HER2/neu negative (ER+/HER2-) breast cancer patients. The aim of this study was to determine if CTC detection at time of surgery in ER+/HER2- predicts early (less than or equal to 5 years) recurrence, and to compare the median recurrence-free survival (RFS) to triple negative (TN) patients.

Methods:

We performed CTC enumeration on 506 patients with non-metastatic breast cancer just prior to surgical resection as part of an IRB approved study. CTCs (per 7.5 ml blood) were identified using the Cell SearchSystem (Menarini Silicon Biosystems). The presence of one or more CTC meeting morphological criteria for malignancy was considered a positive result. Patients with inflammatory breast cancer were excluded from our analysis. Log-rank test and Cox regression analysis were applied to establish the association of CTCs with RFS.

Results:

Median follow-up was 68 months and mean age was 53 years. Eighty-four percent of patients (417/498) had T1/T2 tumors, 63% (307/487) had grade 1 or 2 tumors, and 58% (292/501) had negative lymph nodes. Eighty-three percent (419/506) had ER+/HER2- tumors, and 17% (87/506) were TN. One or more CTC was identified in 22% (91/419) ER+/HER2- patients, and in 28% (24/87) of TN patients. Nine percent (45/506) of patients recurred within 5 years of CTC assessment. Of the 45 patients who relapsed, detection of one or more CTCs predicted shortened RFS. Median RFS for CTC-positive patients was 1.2 years, vs. 2.5 years for CTC-negative patients, irrespective of ER+/HER2- or TN subtype (log-rank P<0.001, HR = 2.71, 95% CI, 1.50 to 4.87).

Conclusions: One or more CTCs identified at surgical resection predicted shortened RFS, irrespective of subtype, in non-metastatic breast cancer patients. This data warrants larger studies to determine if CTC positivity can be used to stratify both ER+ and TN patients who are at increased risk for early recurrence.

Citation Format: Hall C, Meas S, Bowman Bauldry J, Kuerer H, Lucci A. Circulating tumor cell detection predicts early recurrence in patients with non-metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-01-05.

OncotypeDX Recurrence Score Does Not Predict Nodal Burden in Clinically Node Negative Breast Cancer Patients

BACKGROUND

OncotypeDX recurrence score (RS)^® has been found to predict recurrence and disease-free survival in patients with node negative breast cancer. Whether RS is useful in guiding locoregional therapy decisions is unclear. We sought to evaluate the relationship between RS and lymph node burden.

METHODS

Patients with invasive breast cancer who underwent sentinel lymph node dissection from 2010 to 2015 were identified from a prospectively maintained database. Patients were excluded if they were clinically node positive or if they received neoadjuvant chemotherapy. RS was classified as low (< 18), intermediate (18-30), or high (> 30). The association between RS, lymph node burden, and disease recurrence was evaluated. Statistical analyses were performed in R version 3.4.0; p < 0.05 was considered significant.

RESULTS

A positive SLN was found in 168 (15%) of 1121 patients. Completion axillary lymph node dissection was performed in 84 (50%) of SLN-positive patients. The remaining 84 (50%) patients had one to two positive SLNs and did not undergo further axillary surgery. RS was low in 58.5%, intermediate in 32.6%, and high in 8.9%. RS was not associated with a positive SLN, number of positive nodes, maximum node metastasis size, or extranodal extension. The median follow-up was 23 months. High RS was not associated with locoregional recurrence (p = 0.07) but was significantly associated with distant recurrence (p = 0.0015).

CONCLUSIONS

OncotypeDX RS is not associated with nodal burden in women with clinically node-negative breast cancer, suggesting that RS is not useful to guide decisions regarding extent of axillary surgery for these patients.

Multidisciplinary Intraoperative Assessment of Breast Specimens Reduces Number of Positive Margins

BACKGROUND

Successful breast-conserving surgery requires achieving negative margins. At our institution, the whole surgical specimen is imaged and then serially sectioned with repeat imaging. A multidisciplinary discussion then determines need for excision of additional margins. The goal of this study was to determine the benefit of each component of this approach in reducing the number of positive margin.

METHODS

This single-institution, prospective study included ten breast surgical oncologists who were surveyed to ascertain whether they would have taken additional margins based their review of whole specimen images (WSI) and review of serially sectioned images (SSI). These results were compared with the multidisciplinary decisions (MDD) and pathology results. Margin status was defined using consensus guidelines.

RESULTS

One hundred surveys were completed. Margins on the original specimen were positive or close in 21%. After WSI, surgeons reported that they would have taken additional margins in 26 cases, reducing the number of positive/close margins from 21 to 13% (p < 0.001). After SSI, 52 would have taken additional margins; however, the number of positive/close margins remained 13%. MDD resulted in additional margins taken in 56 cases, reducing the number of positive/close margins to 7% (p < 0.001 compared with SSI).

CONCLUSIONS

While surgeon review of specimen radiographs can decrease the number of positive or close margins from 21 to 13%, more rigorous multidisciplinary, intraoperative margin assessment reduces the number of close or positive margins to 7%.

Baseline factors predicting a response to neoadjuvant chemotherapy with implications for non-surgical management of triple-negative breast cancer

BACKGROUND

Patients with triple-negative breast cancer (TNBC) and a pathological complete response (pCR) after neoadjuvant chemotherapy may be suitable for non-surgical management. The goal of this study was to identify baseline clinicopathological variables that are associated with residual disease, and to evaluate the effect of neoadjuvant chemotherapy on both the invasive and ductal carcinoma in situ (DCIS) components in TNBC.

METHODS

Patients with TNBC treated with neoadjuvant chemotherapy followed by surgical resection were identified. Patients with a pCR were compared with those who had residual disease in the breast and/or lymph nodes. Clinicopathological variables were analysed to determine their association with residual disease.

RESULTS

Of the 328 patients, 36·9 per cent had no residual disease and 9·1 per cent had residual DCIS only. Patients with residual disease were more likely to have malignant microcalcifications (P = 0·023) and DCIS on the initial core needle biopsy (CNB) (P = 0·030). Variables independently associated with residual disease included: DCIS on CNB (odds ratio (OR) 2·46; P = 0·022), T2 disease (OR 2·40; P = 0·029), N1 status (OR 2·03; P = 0·030) and low Ki-67 (OR 2·41; P = 0·083). Imaging after neoadjuvant chemotherapy had an accuracy of 71·7 (95 per cent c.i. 66·3 to 76·6) per cent and a negative predictive value of 76·9 (60·7 to 88·9) per cent for identifying residual disease in the breast and lymph nodes. Neoadjuvant chemotherapy did not eradicate the DCIS component in 55 per cent of patients.

CONCLUSION

The presence of microcalcifications on imaging and DCIS on initial CNB are associated with residual disease after neoadjuvant chemotherapy in TNBC. These variables can aid in identifying patients with TNBC suitable for inclusion in trials evaluating non-surgical management after neoadjuvant chemotherapy.

Abstract P2-07-09: CPM rate among individuals with breast cancer who underwent multiplex gene testing for hereditary cancer: Single institution experience

Background: Availability of multiplex gene (MPG) testing for hereditary cancer has led to increase use of panel testing versus single gene testing for hereditary cancer. These panels include high, but also moderate penetrance genes. For some of these genes, associated cancer risk and risk management guidelines do not exist. Furthermore there is a high rate of variant of unknown significant (VUS) findings in non-BRCA genes. Currently, in the absence or minimal available data, health care providers and patients are faced with important risk management decisions, especially regarding preventive surgeries, such as prophylactic mastectomy. Currently, there is no data regarding prophylactic mastectomy rate among patients with breast cancer who underwent (MPG) testing. Therefore, our aim was to evaluate the rate of contralateral prophylactic mastectomy (CPM) in a cohort of individuals who underwent multiplex gene testing. Methods: Eight hundred thirty five patients with breast cancer who underwent MPG testing between the years 2013 and 2016 were identified using Institutional Clinical Cancer Genetics Database. Patients with pathogenic, likely pathogenic variants or who had a VUS were included in the analysis. Results: Of 835 patients with a diagnosis of breast cancer; 105 (13%) had a pathogenic or likely pathogenic mutation: 29 (28%) BRCA1, 26 (25%) BRCA2, 11 (11%) ATM, 2 (2%) BARD1, 3 (3%) BRIP, 9 (9%) CHEK2, 1 (1%) MSH2, 1 (1%) NBN, 5 (5%) PALB2, 4 (4%) PTEN, 1 (1%) RAD51C, 5 (5%) TP53, 4 (4%) CDH1, 2 (2%) MUTYH, 1 (1%) PMS2, 1 (1%) APC (1). A total of 102 (12%) VUS were found. Average age of diagnosis was 44 (Range 21-81). CPM rate was 32% (n=66) for the total cohort. Twenty nine % (n=19) of patients with non-BRCA mutations, 24.2% (n=16) with VUS and 46% (n=31) with BRCA mutations opted for CPM. Conclusion: Overall 32% of breast cancer patients with germline mutations or VUS opt for CPM at our institution. The rate for CPM in non- BRCA mutations carriers is high despite no available data regarding contralateral breast cancer risk and benefit of CPM. This finding should be validated in larger cohorts, including identification of reasons behind decision for CPM in these cohorts.

Citation Format: Elsayegh N, Gutierrez Barrera AM, Kuerer HM, Hernandez ND, Litton JK, Arun BK. CPM rate among individuals with breast cancer who underwent multiplex gene testing for hereditary cancer: Single institution experience [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-07-09.

Which threshold for ER positivity? a retrospective study based on 9639 patients

BACKGROUND

Guidelines for the use of chemotherapy and endocrine therapy recently recommended that estrogen receptor (ER) status be considered positive if ≥1% of tumor cells demonstrate positive nuclear staining by immunohistochemistry. In clinical practice, a range of thresholds are used; a common one is 10% positivity. Data addressing the optimal threshold with regard to the efficacy of endocrine therapy are lacking. In this study, we compared patient, tumor, treatment and survival differences among breast cancer patients using ER-positivity thresholds of 1% and 10%.

METHODS

The study population consisted of patients with primary breast carcinoma treated at our center from January 1990 to December 2011 and whose records included complete data on ER status. Patients were separated into three groups: ≥10% positive staining for ER (ER-positive ≥10%), 1%-9% positive staining for ER (ER-positive 1%-9%) and <1% positive staining (ER-negative).

RESULTS

Of 9639 patients included, 80.5% had tumors that were ER-positive ≥10%, 2.6% had tumors that were ER-positive 1%-9% and 16.9% had tumors that were ER-negative. Patients with ER-positive 1%-9% tumors were younger with more advanced disease compared with patients with ER-positive ≥10% tumors. At a median follow-up of 5.1 years, patients with ER-positive 1%-9% tumors had worse survival rates than did patients with ER-positive ≥10% tumors, with and without adjustment for clinical stage and grade. Survival rates did not differ significantly between patients with ER-positive 1%-9% and ER-negative tumors.

CONCLUSIONS

Patients with tumors that are ER-positive 1%-9% have clinical and pathologic characteristics different from those with tumors that are ER-positive ≥10%. Similar to patients with ER-negative tumors, those with ER-positive 1%-9% disease do not appear to benefit from endocrine therapy; further study of its clinical benefit in this group is warranted. Also, there is a need to better define which patients of this group belong to basal or luminal subtypes.

Abstract P5-13-03: Factors associated with prophylactic mastectomy among BRCA-positive patients with no personal history of breast cancer

Background: The rate of prophylactic mastectomy (PM) has recently increased1. A deleterious mutation in the BRCA1 or BRCA 2 genes is among the major reasons why patients pursue PM 2, 3. Women with BRCA1 or BRCA2 gene mutations have up to an 87% risk to develop an invasive breast cancer (BC), and up to 45% risk for ovarian cancer (OC)2, 3. Most studies evaluating predictors of PM in BRCA mutation carriers are performed among women with breast cancer; however, accurate predictors for PM among unaffected BRCA mutation carriers are less defined. In a single institution study we aimed to evaluate predictors of PM among BRCA carriers with no personal history of breast cancer.

Method: One hundred seventy seven women with no personal history of BC, who tested positive for a BRCA1 or BRCA 2 germline mutation, were included in the study. Patients’ characteristics were obtained from a prospectively maintained research database under an IRB approved protocol at UT MD Anderson Cancer Center. Univariate analyses using chi-square and logistic regression analysis were used to determine predictive factors associated with PM. The patient characteristics examined included age, martial and educational status, bilateral salphingo-oophorectomy (BSO), family history of 1st and 2nd degree relatives with breast (BC) and ovarian cancer (OC), race, and BRCA genetic test result.

Results: Out of the 177 BRCA1 and BRCA 2 positive patients, 51 (29%) elected for PM. The average age for the cohort was 44 years (range 23-91). The majority were Caucasian (81%), and married (72%) with a college degree (64%). One hundred sixty-four (92%) patients had 1st and 2nd degree relatives with BC, 93 (53%) had 1st and 2nd degree relatives with OC, and 85 (48%) had undergone BSO. A logistic regression model was run to identify factors associated with undergoing PM, including family history of OC, family history of BC, BSO and age. Patients with a family history of OC were 2.5 times more likely than those without to have had a PM (p = 0.0125), and patients who had a BSO were 0.137 times less likely to have had a PM (p &lt;.0001). Only 12 patients did not have a family history of BC and none of those patients had a PM, so an Odds Ratio could not be calculated. However, it was determined through the Fisher's exact test that patients with a family history of BC were more likely to undergo a PM (p = 0.0198).

Conclusion: The rate of PM in our cohort was slightly lower than expected. Factors associated with PM included a family history of BC and OC. Interestingly, having had a BSO was associated with lower likelihood of undergoing PM (menopausal status will be further evaluated); possibly due to the knowledge that BSO reduces breast cancer risk.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-13-03.

Abstract P5-14-07: Comparison of infectious complications between breast conserving therapy with catheter-based accelerated partial irradiation and whole breast irradiation

Standard treatment after breast conserving surgery (BCS) has been whole breast irradiation (WBI), however, accelerated partial breast irradiation (APBI) has recently been shown to be an alternative in a select group of patients. APBI has been associated with early postoperative as well as delayed infections. In the current study, we compared rates of infectious complications between patients treated with catheter-based APBI and WBI.

Patients were identified from a single-institution prospective registry from 2009 to 2011. Selection criteria included patients who underwent BCT with either single-entry APBI or WBI and fulfilled criteria for ABPI including ≥50 years, tumor size ≤ 3cm, pN0, and no lympho-vascular invasion. Data regarding treatment, patient comorbidities, and outcomes were obtained. Infectious complications were assessed from the date of APBI catheter insertion or from the date of surgery to start of WBI. Infectious complications were classified as early (≤ 30 days) or delayed (&gt; 30 days). Fisher's exact test was used to compare the rate of infection between APBI and WBI.

91 patients were treated with single-entry catheter-based APBI and 267 patients were treated with WBI. Median follow-up time was 76.2 weeks for APBI patients and 115 weeks for WBI patients. Re-excision was required in 20 patients (21.7%) who underwent APBI and in 51 patients (19.1%) who underwent WBI. Overall, infection occurred in 13 patients (14.1%) who underwent APBI versus 39 patients (14.6%) who underwent WBI. In the APBI group, three (3.3%) patients had infection within 30 days and 10 (10.9%) had infection more than 30 days after catheter insertion. 24 (9.0%) patients had infections within 30 days after surgery and 15 (5.6%) patients occurred more than 30 days after surgery in the WBI group. Patients began WBI within an average of 84 days after surgery. In the APBI group, 4 patients required hospital admission, 5 patients had percutaneous aspiration, and one needed incision and drainage. 8 patients were managed with outpatient oral antibiotics. In the WBI group, 5 patients required hospital admission, 13 patients had percutaneous aspiration, and 30 patients were managed with outpatient oral antibiotics. Diabetes, smoking, and BMI &gt;25 were factors commonly associated with infectious complications in both APBI and WBI but not statistically significant (P = 0.6, 0.09, 0.1. respectively).

In contrast to other studies showing that patients treated with catheter-based APBI have higher rates of infection than patients treated with WBI, our study found no statistically significant difference in infection rates between the two groups. A majority of infections following APBI or WBI can be medically managed as an outpatient basis.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-07.

Pathologic complete response to neoadjuvant chemotherapy with trastuzumab predicts for improved survival in women with HER2-overexpressing breast cancer

BACKGROUND

We sought to determine the prognostic value of pathologic response to neoadjuvant chemotherapy with concurrent trastuzumab.

PATIENTS AND METHODS

Two hundred and twenty-nine women with HER2/neu (HER2)-overexpressing breast cancer were treated with neoadjuvant chemotherapy plus trastuzumab between 2001 and 2008. Patients were grouped based on pathologic complete response (pCR, n = 114) or less than pCR (<pCR, n = 115); as well as by pathologic stage. Locoregional recurrence-free (LRFS), distant metastasis-free (DMFS), recurrence-free (RFS), and overall survival (OS) rates were compared.

RESULTS

The median follow-up was 63 (range 53-77) months. There was no difference in clinical stage between patients with pCR or <pCR. Compared with patients achieving <pCR, those with the pCR had higher 5-year rates of LRFS (100% versus 95%, P = 0.011), DMFS (96% versus 80%, P < 0.001), RFS (96% versus 79%, P < 0.001), and OS (95% versus 84%, P = 0.006). Improvements in RFS and OS were seen with decreasing post-treatment stage. Failure to achieve a pCR was the strongest independent predictor of recurrence (hazard ratio [HR] = 4.09, 95% confidence interval [CI]: 1.67-10.04, P = 0.002) and death (HR = 4.15, 95% CI: 1.39-12.38, P = 0.011).

CONCLUSIONS

pCR and lower pathologic stage after neoadjuvant chemotherapy with trastuzumab are the strongest predictors of recurrence and survival and are surrogates of the long-term outcome in patients with HER2-overexpressing disease.

Abstract S2-3: Disparities in the utilization of axillary sentinel lymph node biopsy among black and white patients with node-negative breast cancer from 2002–2007

Background: Disparities exist in many aspects of standard breast cancer treatment in certain patient populations. In the mid-1990s, axillary sentinel lymph node biopsy (SLNB) was introduced as an alternative to axillary lymph node dissection (ALND) for staging clinically node-negative breast cancer. During the early 2000s, the validity of SLNB was being determined and its technique was being disseminated throughout the surgical community. By the mid to late-2000s, SLNB had been shown to provide accurate axillary staging with lower complications and no difference in survival compared to ALND in node-negative patients. SLNB has now replaced ALND as the accepted method for staging early breast cancer. The purpose of this study is to examine differences in the utilization of SLNB in pathologic node-negative invasive black breast cancer patients compared to white patients as SLNB became standard axillary staging and whether this difference impacted patient complications.

Methods: Using the population-based Surveillance, Epidemiology, and End Results (SEER)-Medicare data, cases of incident, non-metastatic, pathologic node-negative breast cancer in women age≥66 were identified. Patients were considered to have undergone SLNB if specified by SEER records or if a billing claim for axillary lymphatic mapping was identified. Unadjusted associations of SLNB with race were evaluated using the chi-square test. The Cochran-Armitage test evaluated trends over time. Multivariate logistic regression tested whether race was associated with the use of SLNB after adjustment for clinicopathologic factors. Five-year cumulative incidence of lymphedema assessed via ICD-9 diagnosis codes was measured using the Kaplan-Meier method. Adjusted proportional hazards regression evaluated assiciations of race and ALND with lymphedema risk.

Results: Of 31,274 women identified, 1,767 (5.7%) were Black, 27,856 (89%) were White and 1,651 (5.3%) were of other/unknown race. SLNB was performed in 74% of white patients compared to 62% of black patients (P&lt;0.001). Although use of SLNB increased by year for both black and white patients (P&lt;0.001), a fixed disparity in the use of SLNB persisted through 2007.

Abstract P4-15-02: Timing of infectious complications following breast conserving therapy with catheter-based accelerated partial breast irradiation

Background: Accelerated partial breast irradiation (APBI) has been introduced as an alternative to whole breast irradiation as part of breast conserving therapy for selected patients. The long-term outcomes remain under investigation. Previous publications have emphasized early postoperative infections with APBI with less focus on delayed infection. In the current study, we evaluated patients enrolled on a prospective registry trial for infectious complications after treatment with catheter-based APBI.

Methods: Patients who underwent single-entry catheter-based APBI were identified from a single-institution prospective registry from 2009 to 2011. Data regarding treatment, patient comorbidities, complications, and outcomes were obtained from registry and retrospective chart review. Infectious complications were assessed from the date of APBI catheter insertion and were classified as early (≤30 days) or delayed (&gt;30 days). All patients were maintained on oral antibiotics while the catheter was in place.

Results: A total of 91 patients with 92 cases of primary breast cancer were enrolled on a prospective registry at a comprehensive cancer center between 2009 and 2011 and treated with single-entry catheter-based APBI. The median follow-up time was 76.2 weeks. A temporary catheter was placed at the time of initial operation in 40 cases (43.5%) and left in place a median of 6 days prior to definitive catheter insertion. There were 20 patients (21.7%) who required re-excision. Overall, breast infection occurred in 13 (14.1%) patients. Three (3.3%) patients had infection within 30 days of catheter placement and 10 (10.9%) occurred more than 30 days after catheter insertion (median 112.5 days, interquartile range 51–154). Eight patients were managed with oral antibiotics alone on an outpatient basis. The remainder required a combination of admission, intravenous antibiotics, and aspiration of abscess. One patient underwent operative drainage.

Conclusion: We found an overall infection rate of 14.1% in patients treated with catheter-based APBI. This is consistent with other reports; however, we found that the majority of infections occurred more than 30 days after definitive catheter placement. Vigilance for infectious complications must continue beyond the immediate treatment period in patients undergoing catheter-based APBI. Most infections following APBI can be managed on an outpatient basis without operative intervention.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-15-02.

Abstract P1-07-09: Estrogen receptor positivity: 10% or 1%?

Background. Guidelines by the American Society of Clinical Oncology and the College of American Pathologists recently recommended that estrogen receptor (ER) status should be considered positive if 1% of tumor cells demonstrate positive nuclear staining by immunohistochemistry. Historically, 10% nuclear staining defined ER-positive status and impacted decision-making regarding endocrine therapy. Currently, no optimal threshold exists for ER either by clinically validating patient outcomes in prospective clinical trials or independently validated from systematically collected archived specimens from randomized clinical trials. In this study, we examined patient, tumor and treatment differences among patients by ER status: ER-positive ≥10%, ER-positive 1–10% and ER negative (&lt;1%). We compared recurrence-free survival (RFS), disease-specific survival (DSS) and overall survival (OS) among patients with different ER staining categories and adjusted by clinical stage, adjuvant chemo and endocrine therapy.

Method. Patients with primary breast carcinoma treated at our center who had complete ER status from January 1990 to December 2011 were included in this study. Patients were excluded if they presented with recurrent or metastatic disease. For statistical analyses, patients who underwent surgery for breast cancer were separated into three groups: ER-positive ≥10%, ER-positive 1–10% and ER negative. Analyses comparing various clinical and pathologic characteristics among patients with different ER status were performed. Survival rates were calculated by the Kaplan-Meier method.

Result. Patients whose tumors were ER-positive 1–10% (2.7%) were younger (median age 53 Vs. 56 years, P &lt; 0.0001), more likely to have invasive ductal carcinoma histology with more advanced disease (clinical stage II/III 50.4% Vs. 37.3%, p &lt; 0.0001), and were more likely to receive neoadjuvant chemotherapy (40.9% vs. 25.6%, P &lt; 0.0001), adjuvant chemotherapy (45.5% vs. 31.2%, P &lt; 0.0001), and less likely to receive adjuvant endocrine therapy (19.5% vs. 78.6%, P &lt; 0.0001) compared to patients with ER-positive tumors ≥ 10%. They were also more likely to have HER-2-positive (29.1% vs. 13.4%, P &lt; 0.0001) and grade III disease (82.1% vs. 29.6%, P &lt; 0.0001). Compared to patients with ER negative, patients with ER-positive 1–10% had earlier stage disease (clinical stage II/III 50.4% Vs. 59.3%, p = 0.01), were less likely to receive neoadjuvant chemotherapy (40.9% vs. 48.2%, p = 0.02), and more likely to receive adjuvant endocrine therapy (19.5% vs. 12.6%, p = 0.002). At a median follow-up of 5.1 years, patients with ER-positive 1–10% had worse RFS, DFS and OS rates compared to patients with ER-positive tumors ≥ 10%. The RFS, DFS and OS rates between patients with ER-positive 1–10% and ER negative did not differ significantly. Patients with ER-positive 1–10% and negative still had worse RFS, DSS and OS rates compared to patients with ER-positive tumors ≥ 10% after adjusted by clinical stage, adjuvant chemo and endocrine therapy.

Conclusion. Patients whose tumors are ER-positive at 1–10% have clinical and pathologic characteristics different from those whose tumors are ER-positive ≥10%. Similar to patients whose tumors are ER negative, those with ER-positive disease at 1–10% do not appear to benefit from endocrine therapy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-07-09.

P4-10-06: Evaluation of BRCAPro Risk Assessment Model in Patients with Ductal Carcinoma In Situ

Background: The BRCAPRo model is used to predict a patient's likelihood to possess a BRCA1 or BRCA2 gene mutation based upon personal and family history. Ductal carcinoma in situ (DCIS) is considered a non-invasive condition which can progress to an invasive breast cancer if left untreated. Currently, DCIS is not specifically accounted for in the BRCAPro model, thereby causing DCIS to be weighted in the same manner as an invasive breast cancer diagnosis. Historically, a diagnosis of DCIS has been entered as having developed into an invasive breast cancer ten years later. However, there are no standard guidelines of how DCIS should be entered. We sought to determine if there were any differences in how DCIS was treated in the BRCAPro model to predict the more effective method in calculating the BRCAPro. Methods: Women with pure DCIS, who were referred for genetic counseling and underwent genetic testing, were included in the study. The likelihood of carrying a BRCA mutation was calculated using the BRCAPRO model (Version 5.1). Patient characteristics which were entered into the BRCAPro model include: tumor markers (estrogen receptor-ER and progesterone receptor-PR), history of oophorectomy prior to diagnosis, family history of 1st and 2nd degree relatives with breast and ovarian cancer, race and Ashkenazi Jewish ancestry. Each patient's BRCAPro risk estimate was calculated and compared by entering DCIS at the presenting age of diagnosis and by adding 10 years to the age of diagnosis. Descriptive statistics and a student's t-test were used to compare BRCAPro estimates between the two groups. Results: Ninety-five patients with pure DCIS underwent genetic counseling and testing. The average age of DCIS diagnosis was 45 years (range 26–65). Of the 95 DCIS patients included in the study 21% (n=20) tested positive for a BRCA gene mutation (8 BRCA1 and 12 BRCA2), 77% (n=74) test negative and 0.01% (n=1) had a variant of uncertain significance. Overall, DCIS patients who tested positive for a BRCA mutation had a higher BRCAPro (40%) than patients who tested negative (12%) when presenting age of diagnosis was assessed. When 10 years was added, the BRCAPro estimate was still higher amongst BRCA positive patients (28%) than BRCA negative patients (8%). The mean BRCAPro probability when DCIS was entered at presenting age of diagnosis was 18% (0.1−95.4) versus 12% (0.1−89.9) when calculated 10 years later. Conclusion: In our cohort there was no significant difference in BRCAPro probability whether DCIS was entered at the presenting age of diagnosis or 10 years later (p=0.1). However, future studies are needed to determine the most effective method to incorporate DCIS into the BRCAPro model in order to determine those individuals who may or may not be at increase risk to possess a BRCA gene mutation.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-10-06.

P4-07-11: Circulating Tumor Cells after Neoadjuvant Therapy Predict Outcome in Stage I to III Breast Cancer

Introduction: Circulating tumor cells (CTCs) predict outcome in metastatic breast cancer, but their significance is unclear in non-metastatic patients. Furthermore, it is unclear if the presence of CTCs after completion of neoadjuvant chemotherapy (NACT) predicts worse outcome. The purpose of this study was to determine if CTCs after NACT predicts worse outcome.

Methods: Clinical stage I-III breast cancer patients seen at a single tertiary cancer center provided informed consent to participate in an IRB-approved study involving collection of blood (7.5 ml x 2 tubes) at the time of surgery for their primary breast cancer. CTCs were detected using the Cell SearchTM system. A positive result was defined as the presence of one or more cells per 7.5 ml blood since the threshold for positivity has not been established in non-metastatic breast cancer. Statistical analyses used chi-square and Fischer's exact test.

Results: One hundred and twenty patients were prospectively enrolled. Median age was 50 years and median follow-up was 33 months. Eight percent of patients had T1 disease, 35% T2, 18% T3, and 39% T4. Fifty-three percent of patients (63/120) had hormone receptor positive disease. Thirty-two percent of patients (38/120) were HER-2 positive. Thirty percent (36/120) were triple negative. Seventy-eight percent (91/120) had lymph node positive disease. Two or more CTCs were present in 9% of patients (11/120). Of the 11 patients who died, 3 had 2 or more CTCs (P=0.08). Of the 20 who relapsed, 6 had 2 or more CTCs (P=0.0019).

Conclusions: Presence of two or more CTCs after NACT predicted worse relapse free survival in patients with stage I-III breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-07-11.

P3-07-05: Nomogram Incorporating SLN Metastasis Size Provides the Most Accurate Prediction of Non-SLN Involvement in Breast Cancer Patients

Introduction: The finding of metastatic disease in the axillary nodes remains an important factor that guides adjuvant therapy decisions in breast cancer. The value of completion axillary lymph node dissection (ALND) may not be the same in all patients and determining the risk of non-SLN involvement can be a guide in surgical decision making. We recently developed a nomogram that incorporates the maximum SLN metastasis size to predict non-SLN axillary involvement (Mittendorf et al., Ann Surgery 2011,in press). The purpose of this study was to compare the accuracy of this nomogram to another widely used nomogram that does not include SLN metastasis size.

Methods: We queried a prospective breast cancer database for patients with clinically negative nodes undergoing sentinel node biopsy who did not receive neoadjuvant therapy. We identified 431 patients with invasive breast cancer treated from 1996 to 2007 who had a positive SLN and underwent completion ALND. We evaluated clinicopathologic data including histology, multifocality, nuclear grade, pathologic tumor size, number of SLNs recovered, number of positive SLNs, maximum SLN metastasis size, presence of extranodal extension, hormone receptor status, and presence of lymphovascular invasion. Data were entered into our nomogram and the nomogram that does not include SLN metastasis size. The accuracy of the 2 nomograms in predicting non-SLN axillary metastasis was compared in all patients and in subgroups of patients based on burden of disease in the SLN.

Results: For the entire cohort of 431 women with positive SLNs, our SLN size nomogram was more accurate in the detection of non-SLN disease (area under the receiver operating characteristic curve [AUC] 78.3% vs. 72.4%, p=0.01). Whether or not SLNs were subjected to frozen section did not influence the relative accuracies of the 2 nomograms. When patients were analyzed by burden of disease in the SLNs, our SLN size nomogram was more accurate in predicting non-SLN disease in patients with macrometastases in the SLN (AUC 77.3% vs. 70.3%, p=0.008). There was no significant difference in the accuracy of the 2 nomograms for patients with isolated tumor cells or micrometastases in the SLNs.

Conclusions: Our nomogram incorporating SLN metastasis size with other clinicopathologic factors is the most accurate predictor of the risk of non-SLN metastasis in patients with a positive SLN. The SLN size nomogram is highly accurate in women with macrometastases, who may benefit the most from completion ALND. Using a nomogram with SLN metastasis size can provide the most accurate information for patient counseling and surgical decision making.

P4-07-07: Circulating Tumor Cells Predict Survival in Non-Metastatic Breast Cancer

Background: Circulating tumor cells (CTCs) predict outcome in metastatic breast cancer (BC), but their prognostic significance in non-metastatic BC is unclear. This study determined whether CTCs could be identified in non-metastatic BC patients and 2) if CTCs predict relapse-free and overall survival.

Methods: Clinical stage I-III BC patients seen at a single tertiary cancer center provided informed consent to participate in an IRB-approved study involving collection of blood (7.5 ml x 2 tubes) before systemic therapy and at the time of surgery for their primary BC. CTCs were detected using the Cell SearchTM system. A positive result was defined as the presence of two or more cells per 7.5 ml blood since a threshold for positivity has not been established in primary BC. Statistical analyses were done using STATA-IC 11 software.

Results: We prospectively evaluated 291 patients. Mean age was 54 years, and median follow-up was 30 months. 54% (157) had T1 tumors, 36%(104) T2, 6% (18) T3, and 4%(12) had T4 disease; 37% (107/289) were clinically node-positive (LNs) by axillary ultrasound and FNA. Two or more CTCs were identified in 10% (29) patients. Seventy-seven percent (225) patients were hormone receptor positive, 11% (32) were HER2 positive while 16% (48) expressed no receptors. Sixteen percent (48) were tumor grade 1, 50% (143) were grade 2 and 34% (98) were grade 3. Systemic chemotherapy and/or endocrine therapy were administered in 80% (233/289) of patients. Sixty-eight percent (167/244) of patients were post-menopausal. Additionally, there was no significant correlation between CTCs with primary tumor size, lymph node status, estrogen or progesterone receptor status, HER2 amplification or tumor grade. Thirty-eight percent (6/16) of all relapses occurred in patients with 2 or more CTCs (HR: 4.48 (95% C.I. 1.61−12.45), Logrank P 0.002) while 40% (4/10) of all deaths occurred in patients with 2 or more CTCs (HR: 4.54 (95% C.I. 1.27−16.25), Logrank P 0.011).

Conclusions: CTCs were a significant predictor of disease-free and overall survival in non-metastatic breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-07-07.

P5-01-17: HER2 Amplification in Primary Tumor: A Potential Marker for Presence of Circulating Tumor Cells in Inflammatory Breast Cancer Patients?

Background: Inflammatory breast cancer (IBC) is a rare but aggressive form of invasive breast cancer accounting for 3–6% of all cases and have higher rates of distant recurrence. Circulating tumor cells (CTCs) are known to predict outcome in metastatic breast cancer (BC) patients, but little is known about their prognostic significance in non-metastatic BC. We hypothesized that CTCs can be identified in patients with IBCs and may correlate with primary tumor characteristics. Methods: All patients had blood samples collected at the time of primary surgery. CTCs (per 7.5 ml blood) were detected using the Cell Search™ system (Veridex) and were defined as nucleated cells lacking CD45 but expressing cytokeratins (CK) 8, 18, or 19. The presence of ≥ 1 epithelial cells meeting morphologic criteria for malignancy was considered a positive result. Statistical analyses employed Chi square and Fisher's exact tests using STATA IC 11. Results: We prospectively evaluated 41 IBC patients enrolled in an IRB approved protocol undergoing surgery for stage I-III breast cancer. Median follow-up was 30 months. Mean age was 52 years. Thirty five patients (94%) had positive lymph nodes (LNs) at presentation, 30 (75%) had high-grade tumors and 20 (53%) had lymphovascular invasion. Eleven patients (28%) were ER positive, 11 (27%) were PR positive and 18 (44%) were HER2 positive. IBCs were more likely to be high grade (P&lt;0.0001), ER negative (P&lt;0.0001), PR negative (P&lt;0.0001), HER2 positive (P&lt;0.0001), High Ki-67 (P= 0.005) and had a BMI of more than 25kg/m2 (P=0.04). Eleven (27%) patients were CTC positive. CTCs were more likely be found in HER2 positive (8/18; 44%) vs. HER2 negative primary tumors (3/20; 15%) [OR= 4.53; 95% C.I. = 1.02−19.52; P= 0.04]. We found no statistically significant correlations between primary tumor characteristics (ER, PR, LNs, high grade) and presence of CTCs. Conclusions: About a quarter of IBC patients had CTCs at the time of primary surgery. In these patients HER2 overexpression predicted the presence of CTCs. Studies with longer follow-ups is needed to determine if CTCs predicted survival.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-17.

P4-06-02: Microscopic Disease in Blood and Bone Marrow Predicts Survival in Early Stage Breast Cancer

Background

Disseminated tumor cells (DTCs) in the bone marrow have been identified in 30% of stage I - III breast cancer (BC) patients and predict survival. Circulating tumor cells (CTCs) in the blood predict outcome in metastatic BC, but their prognostic significance in primary BC is unclear. This study determined whether: 1) DTCs and CTCs could be identified in significant numbers of non-metastatic BC patients and 2) if these cells predict relapse-free (RFS) and overall survival (OS).

Methods: Clinical stage I-III BC patients seen at a single tertiary cancer center provided informed consent to participate in an IRB-approved study involving collection of blood (7.5 ml x 2 tubes) and bone marrow (10 ml from bilateral iliac crests), and at the time of surgery for their primary BC. DTCs were assessed using an anti-cytokeratin antibody cocktail (MNF 116, CK 8,18, and 19, CAM 5.2, and AE1/AE3) following ficoll enrichment and cytospin. A positive result for DTCs was defined by presence of one or more CK-positive cells meeting morphologic criteria for malignancy. CTCs were detected using the Cell SearchTM system. A positive result was defined as the presence of one or more cells per 7.5 ml blood since a threshold for positivity has not been established in non-metastatic BC. Statistical analyses used chi-square and Fischer's exact test.

Results: We prospectively evaluated 313 patients. Mean age was 53 years, and median follow-up was 32 months. Forty-two percent of patients (131) had T1 tumors, 36% (112) T2, 10% (30) T3, and 13% (40) had T4 disease. Forty-five percent of patients (141/312) had positive lymph nodes. DTCs were identified in 29% (91/313) and CTCs in 25% (79/313) of all patients. Seven percent (21/313) of patients had both DTCs and CTCs. In the overall cohort, 26 (8%) patients relapsed and 15 (5%) died. Ten percent (9/91) of DTC positive patients died compared to 3% (6/222) of those who did not have DTCs (p=0.01). Similarly, 6% (7/79) of those who had CTCs died compared to 3% (8/234) of those who did not (p=0.03). Fifteen percent (12/79) of CTC positive patents relapsed compared to 6% (14/234, P=0.01) of those who were CTC negative. Simultaneous presence of DTCs and CTCs was a strong predictor of RFS (log rank p=0.030, HR= 2.8, 95% C.I. 1.20- 8.10) as well as OS (log rank p=0.026, HR= 3.66, 95% C.I. 1.03- 13.00) at 2 years. Combined presence of DTCs and CTCs was a predictor of outcome and these findings persisted after adjusting for variables including hormone receptor status, HER2 status, primary tumor size, grade, and preoperative lymph node status. There was no significant correlation between DTCs and/or CTCs with other primary tumor characteristics.

Conclusions: Circulating and disseminated tumor cells can be identified in a significant number of non-metastatic breast cancer patients. Both CTCs and DTCs predicted outcome, and their combined presence was an independent predictor of survival.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-06-02.

P4-06-04: Detection of HER2 Gene Amplification in Circulating Tumor Cells and Disseminated Tumor Cells by Fluorescence In Situ Hybridization Using OncoCEE™

BACKGROUND: The status of HER2 gene amplification in circulating tumor cells (CTCs) and disseminated tumor cells (DTCs) might provide useful information for monitoring response to trastuzumab therapy, and may provide a basis for consideration of trastuzumab in patients with HER2 negative primary tumors who have HER2 positive CTCs and/or DTCs. The majority of techniques utilized for detection of minimal residual disease are limited in their ability to allow detailed phenotypic and genotypic evaluation of the cells. We report the utility of a microfluidic platform (OncoCEE™,Biocept, San Diego) for detecting HER2 gene amplification in CTCs and DTCs in patients with non-metastatic breast cancer.

METHODS: Peripheral blood (10ml) and bone marrow (BM) (1-2ml) were collected from patients with clinical stage I-III breast cancer in acid citrate dextrose solution (BD, Franklin Lakes, NJ) and anti-clumping reagent (OncoCEE-Sure™). Mononuclear cells were recovered using a Percoll density gradient method, incubated with a mixture of 10 primary capture antibodies (Abs), introduced into CEE™ microchannels, stained with fluorescent anti cytokeratin (CK) and CD45 abs and finally processed for fluorescence in situ hybridization (FISH) using probes specific to centromere 17 (spectrum green) and HER2 (spectrum arrange). The ratio of HER2:CEP17 &gt;2.2 in any CK+/CD45- and CK-/CD45- cell was regarded as positive for HER2 gene amplification.

RESULTS: Peripheral blood and/or BM from 78 patients (65 BM; 70 blood; 57 matched blood and BM) with T1NO (39), T1N1 (8), T2N0 (12), T2N1 (2), T2N2 (1), T2N3 (3), T3N0 (2), T3N1 (2), T3N2 (1), T4N0(5), T4N1 (3), with HER2+ (n=12) and HER2− (n=58) primary invasive breast tumors were studied. The 12 patients with HER2+ primary tumors had HER2+ DTCs in 3/12 (25%) and HER2+ CTCs in 1/9 (11%) cases respectively. HER2+ DTCs and HER2+ CTCs occurred in 12/55 (24%) and in 4/63 (6%) of the patients with HER2− primary breast tumors. HER2+ CTCs and DTCs occurred simultaneously in only 2 patients and in either blood (3) or BM (13) in the remaining patients.

CONCLUSION: 1. The cell enrichment and extraction microfluidic technology (OncoCEE™) provides a sensitive platform for evaluation of HER2 gene amplification of CTCs and DTCs.

2. HER2+ primary tumors were associated with either HER2+ CTCs or DTCs in 25% of the patients.

3. HER2+ CTCs or DTCs occurred in 28% of patients with HER2−primary tumor.

4. Discordant HER2 status was contributed mainly by HER2+ DTCs occurring in HER2 - primary tumors.

5. The clinical significance of evaluating the status of HER2 gene amplification in CTCs and DTCs in the management of patients with breast cancer needs to be evaluated prospectively in larger clinical trials.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-06-04.

Six-year analysis of treatment-related toxicities in patients treated with accelerated partial breast irradiation on the American Society of Breast Surgeons MammoSite Breast Brachytherapy registry trial

BACKGROUND

The American Society of Breast Surgeons (ASBrS) enrolled women in a registry trial to prospectively study patients treated with the MammoSite RTS device. This report presents 6-year data on treatment-related toxicities from the trial.

METHODS

A total of 1449 primary early-stage breast cancers were treated with accelerated partial breast irradiation (APBI) using the MammoSite device (34 Gy in 10 fractions) in 1440 women. Of these, 1255 case (87%) had invasive breast cancer (IBC) (median size = 10 mm) and 194 cases (13%) had ductal carcinoma in situ (DCIS) (median size = 8 mm). Median follow-up was 59 months. Fisher exact test was performed to correlate categorical covariates with toxicity.

RESULTS

Breast seromas were reported in 28% of cases (35.5% with open cavity and 21.7% with closed cavity placement). Also, 13% of all treated breasts developed symptomatic seromas, and 77% of these seromas developed during the 1st year after treatment. There were 172 cases (11.9%) that required drainage to correct. Use of chemotherapy and balloon fill >50 cc were associated with the development of symptomatic seromas. Also, 2.3% of patients developed fat necrosis (FN). The incidence of FN during years 1 and 2 were 0.9% and 0.8%, respectively. Seroma formation, use of hormonal therapy, breast infection, and A/B cup size were associated with fat necrosis. There were 138 infections (9.5%) recorded; 98% occurred during the 1st year after treatment. Chemotherapy and seroma formation were associated with the development of infections.

CONCLUSIONS

Treatment-related toxicities 6 years after treatment with APBI using the MammoSite device are similar to those reported with other forms of APBI with similar follow-up.

Abstract P4-10-14: Risk of Ipsilateral Breast Events in Patients with Ductal Carcinoma In Situ after Local Excision

Purpose

To determine the risk of ipsilateral breast events (IBE) in patients with ductal carcinoma in situ (DCIS) treated with local excision. Patients and Methods

We retrospectively identified 692 patients who had undergone local excision from 1968 through 2007 at our institution with a final diagnosis of DCIS. Factors evaluated included age, race, method of detection, menopausal status, bloody nipple discharge, histological type, final margin status, grade, status at last follow-up and recurrence information. An IBE was defined as the development of breast cancer of invasive histology or DCIS (but not lobular carcinoma in situ) in the treated breast.

Results

At a median follow-up of 6.1 years, 47 (6.8%) IBEs occurred in the 692 patients. Among 47 IBE, 23 (48.9%) were DCIS and 19 (40%) were invasive cancer and 5 (10.6%) were unknown type of IBE. Patients with IBE were younger (53 Vs 57, P=0.04). Whether patients had final positive margin (4 patients) had no influence on IBE. Use of a Cox proportional hazards model showed that patients with high grade tumors and those who did not receive adjuvant radiation therapy (XRT) were more likely to have an IBE (Hazard ratio: 4.1, 95% CI:1.3-13.4, P=0.019). The 5-year rate of ipsilateral breast events for patients with grade III DCIS who did not undergo adjuvant radiation therapy was significantly higher than all others: 15% vs. 4.6% compared to grade I/II with XRT, 15% vs. 10% compared to grade I/II without XRT, and 15% vs. 9.9% in grade III with XRT (P=0.017). Conclusions

Patients with low or intermediate grade DCIS have an acceptably low rate of ipsilateral breast events after local excision with adjuvant radiation therapy. Patients with high-grade lesions treated without irradiation have a rate of IBE of 15% at 6 years, suggesting that excision alone is inadequate treatment in this group. Further follow-up is necessary to document long-term results.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-10-14.

Predictors of Persistent Micrometastatic Disease after Neoadjuvant Chemotherapy

Introduction: Patients who receive neoadjuvant chemotherapy (NAC) for breast cancer typically do not receive further cytotoxic chemotherapy after surgery. We hypothesized that some patients would have micrometastatic disease in the bone marrow (disseminated tumor cells, DTCs) or peripheral blood (circulating tumor cells, CTCs) after NAC. This study documented rates and factors predicting DTCs and CTCs after NAC.Methods: We prospectively evaluated patients undergoing surgery for stage I-III breast cancer. All patients had blood and bone marrow samples taken after completing systemic NAC. CTCs (per 7.5ml blood) were detected using the CellSearchTM system (Veridex). CTCs were defined as nucleated cells lacking CD45 but expressing cytokeratins (CK) 8, 18, or 19. DTCs were assessed using anti-CK antibody cocktail (AE1/AE3, CAM5.2, MNF116, CK8 and 18) following cytospin. The presence of ≥1 CK positive cells and ≥1 epithelial cells meeting morphologic criteria for malignancy was considered a positive result for DTCs and CTCs, respectively. Clinicopathologic factors correlated with DTCs and CTCs and response after NAC included: Her2/neu, estrogen receptor (ER), progesterone receptor (PR) and COX2 status as well as tumor size and grade. Complete pathologic response (pCR) was defined as lack of any residual invasive disease in primary tumor and regional lymph nodes after NAC. Statistical analyses used chi-square and Fischer's exact test.Results: Results were available for 53 patients who had bone marrow and blood collected after NAC. Median follow-up was 26 months. Mean age was 52 years. NAC included anthracyclines and taxanes +/- trastuzumab. Forty percent of patients had either DTCs or CTCs after NAC. Six patients had DTCs amongst 11 patients (55%) who received trastuzumab as compared to those who did not 6/33 (18%), P=0.019. DTCs and CTCs were found in 10/43 patients (23%) and 11/43 patients (27%), respectively. Factors predicting the presence of DTCs after NAC were Her2/neu positivity (P=0.001) and COX2 positivity determined in the primary tumor at diagnosis (P=0.04). No statistically significant correlations were found between CTCs after NAC and primary tumor characteristics. Thirty percent of patients with evidence of DTCs and 10% with CTCs had a pCR. Among the 7 patients with pCR after NAC, 2 (28%) had DTCs and 2 (28%) had CTCs. Factors predicting pCR following NAC were Her2/neu positivity (P=0.0003) and ER negativity (P=0.044). In our analysis, the best predictor of the presence of DTCs and the most likely reason for pCR following NAC was Her2/neu positivity.Conclusions: A significant number of patients have persistent DTCs and/or CTCs after NAC. Interestingly, HER2 positive patients were more likely to have pCR but were also more likely to show persistence of DTCs following NAC. Follow-up is needed to determine if these patients comprise groups at higher risk for recurrence, and therefore benefit from additional chemotherapy or targeted therapies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3020.

3-Year Follow-Up of the Partial Breast Irradiation Trial for DCIS Using the MammoSite® Brachytherapy Balloon Catheter

Purpose: To report the 3-year median follow-up of a prospective Phase II partial breast irradiation (PBI) trial utilizing the MammoSite® interstitial balloon as the sole radiation therapy treatment after lumpectomy for ductal carcinoma in situ (DCIS).Materials and Methods: One hundred and thirty-three patients were enrolled from May 2003 through January 2006 to reach the 100-patient partial breast irradiation (PBI) target goal of 34 Gy in 10 fractions, 1 cm peripheral to the MammoSite® balloon surface, b.i.d. with Iridium192 HDR brachytherapy. The eligibility criteria were age 45, unicentric pure DCIS, mammographic size ≤3cm, negative margin of ≥1 mm, gross pathology size ≤5 cm, clinically node negative, post-lumpectomy mammogram absent of residual microcalcificaion. A USC/VNPI score was then calculated based on age, tumor size, margin width, and nuclear grade [ref: Silverstein MJ, Am J Surg 2003;186(4):337-343]. Placement of the balloon was performed at the time of lumpectomy or post-lumpectomy with a required minimum distance of the balloon surface to skin (skin bridge) of 5 mm. Data was collected at enrollment, at implant, 3 and 6-months, then yearly for local control, cosmesis (Harvard Scale), toxicity, adverse events, disease-free survival, cause-specific survival, and contralateral breast failure. Local recurrence is defined as either invasive or non-invasive within the target volume. Ipsilateral elsewhere recurrence (IER) is defined as invasive or non-invasive outside of the target volume.Results: Of the 133 patients enrolled, thirty-three were not treated for the following reasons: less than 5 mm skin bridge (n=13), poor cavity conformance (n=10), positive margin (n=3), microinvasion (n=3), MD decision (n=2), patient request (1), and other (1). The nuclear grade distribution of the tumors were: NG1(17%), NG2(44%), and NG3(39%). The mean age was 60.8 years. The mean tumor size was 10.6 mm; mean closest surgical margin was 6.8 mm (R=0.1-40mm); post-lumpectomy placement in 72%; mean skin bridge distance was 13 mm with 89% ≥7mm. No patients have been lost to follow-up, and at a median 3-year follow-up, the cosmetic results have been rated as excellent/good in 94 and fair in 6 patients. There have been only four recurrences, all non-invasive with the following histological patterns listed in the table below. One was an IER.Recurrence DetailsCase No.Months Since PlacementInvasiveUSC/VNPI ScoreOriginal Tumor GradeComedo Necrosis18No93Yes211No83No317No62Yes432No52Yes No serious adverse events were reported with an infection rate of 9% (7 breast infections; 2 cellulitis).Conclusion: This is the longest reported prospective Phase II study using a PBI technique for pure DCIS patients, and continues to demonstrate the efficacy of the MammoSite® balloon for treating pure DCIS breast tumors, with no new recurrences since our last report at SABCS 2007. All the recurrences were noninvasive, and had at least one or more risk factors of a high USC/VNPI score, high nuclear tumor grade, or had a comedo necrosis pattern. There have been no recurrences in nuclear grade 1 or 2 patients in the absence of a comedo necrosis pattern. The cosmesis also continues to be excellent or good long-term in 96% patients.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 952.

Effect of modest delays in primary surgical treatment on progression of tumor size in breast cancer patients

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Background: Evaluation of medical co-morbidities, coordination of reconstructive surgery and referral to tertiary care centers can delay surgical treatment in breast cancer. These delays raise concerns for tumor progression in the interim. We evaluated the time from initial imaging at a cancer center to surgical treatment and the change in tumor size. Methods: We identified 823 patients who underwent surgery as their first therapeutic modality for invasive breast cancer diagnosed from December 2003 to September 2005. Baseline tumor size was determined by mammogram (MMG) and ultrasound (US) reports, and tumor size at surgery was determined by pathology reports. Results: The median time from imaging at our facility to surgery was 0.69 months (range 0.03 to 4.34). Multivariate modeling indicated that older patient age, undergoing total mastectomy, and undergoing reconstruction predicted a longer time from initial imaging to surgery. Comparing radiographic to pathologic size, a moderate correlation was demonstrated for both MMG (Spearman r = 0.58; p < 0.0001) and US (Spearman r = 0.66, p < 0.0001). Pathologic size was the same as MMG size in 14%, smaller in 49%, and larger in 37% of patients. Differences in tumor size estimates were not significantly associated with time lapse between MMG and surgery, but in a multivariate model, MMG tumor size, tumor histology, and tumor grade were significant predictors (p < 0.0001 for all) of differences in mammographic and pathologic size. The pathologic tumor size was the same as US in 10%, smaller in 38%, and larger in 52% of patients. Time lapse to surgery was not significantly associated with differences in US and pathologic tumor size. In a multivariate model, US tumor size (p < 0.0001), tumor histology (p = 0.0006) and tumor grade (p = 0.005) were significant predictors of differences in US and pathologic tumor size estimates. Conclusions: There is no evidence that time lapse from initial imaging to surgical intervention leads to significant changes in tumor size thus allowing patients to complete preoperative workup and planning without significant clinical disease progression.

No significant financial relationships to disclose.

Hormone receptor status and pathologic response of HER2-positive breast cancer treated with neoadjuvant chemotherapy and trastuzumab

BACKGROUND

The aim of this study was to compare the extent of pathologic response in patients with HER2-positive (HER2+) breast cancer treated with standard neoadjuvant chemotherapy, with or without trastuzumab (H), according to hormone receptor (HR) status.

PATIENTS AND METHODS

We included 199 patients with HER2+ breast cancer from three successive cohorts of neo-adjuvant chemotherapy on the basis of paclitaxel (Taxol) (P) administered weekly (w) or three weekly (3-w), followed by 5-fluorouracil (F), doxorubicin (A) or epirubicin (E), and cyclophosphamide (C). Residual cancer burden (RCB) was determined from pathologic review of the primary tumor and lymph nodes and was classified as pathologic complete response (pCR) or minimal (RCB-I), moderate (RCB-II), or extensive (RCB-III) residual disease.

RESULTS

In HR-positive (HR+) cancers, a higher rate of pathologic response (pCR/RCB-I) was observed with concurrent H + 3-wP/FEC (73%) than with 3-wP/FEC (34%, P = 0.002) or wP/FAC (47%; P = 0.02) chemotherapy alone. In HR-negative (HR-) cancers, there were no significant differences in the rate of pathologic response (pCR/RCB-I) from 3-wP/FAC (50%), wP/FAC (68%), or concurrent H + 3-wP/FEC (72%).

CONCLUSIONS

Patients with HR+/HER2+ breast cancer obtained significant benefit from addition of trastuzumab to P/FEC chemotherapy; pathologic response rate was similar to that seen in HR-/HER2+ breast cancers.

Residual specimen cellularity after neoadjuvant chemotherapy for breast cancer

BACKGROUND

Neoadjuvant chemotherapy for breast cancer reduces tumour cellularity, the percentage of the primary tumour area that is composed of invasive tumour cells. Minimal residual tumour cellularity (5 per cent or less of tumour area composed of invasive tumour cells) may be associated with an increased risk of false-negative intraoperative margins. The aim of this study was to evaluate the incidence of minimal residual tumour cellularity after neoadjuvant chemotherapy and its impact on the frequency of false-negative margins and conversion from breast-conserving surgery to mastectomy.

METHODS

The final pathology slides of 510 patients who had surgery after neoadjuvant chemotherapy were reviewed.

RESULTS

Of 396 patients with residual invasive breast cancer after neoadjuvant chemotherapy, 100 specimens (25.3 per cent) had minimal residual cellularity; this was more frequent in patients with invasive lobular carcinoma (17.0 versus 5.1 per cent; P < 0.001) or well and moderately differentiated carcinoma (68.0 versus 52.4 per cent; P = 0.007). Among 149 patients who had initial breast-conserving surgery, false-negative intraoperative margin rates were 23 per cent in specimens with minimal and 13.8 per cent in those with higher residual cellularity (P = 0.210). There was no significant difference in the rate of conversion to mastectomy between the groups.

CONCLUSION

Minimal residual cellularity after neoadjuvant chemotherapy occurred in about 25 per cent of specimens, but did not alter the rate of false-negative intraoperative margins.

The impact of hormone receptor status on pathologic response of HER2-positive breast cancer treated with neoadjuvant chemotherapy with or without trastuzumab

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Background: The aim of this study was to compare the extent of pathologic response in HER2-positive patients treated with standard neoadjuvant chemotherapy with or without trastuzumab according to hormone receptor (HR) status. Methods: The study included 199 patients with HER2-positive disease treated in clinical trials of neoadjuvant chemotherapy. Eighty-nine patients treated with 3- weekly paclitaxel and concurrent trastuzumab followed by 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) were compared with 110 patients treated with weekly or 3-weekly paclitaxel followed by FEC or FAC. Residual cancer burden (RCB), a measurement of residual disease (RD) from pathologic review of the primary tumor and lymph nodes, was classified as pathologic complete response (pCR), RCB-I (near-pCR, minimal RD), RCB-II (moderate RD), or RCB-III (extensive RD). RCB was compared between treatment groups according to HR status. Results: In HR-negative patients, similar pCR rates were achieved with weekly T/FAC as with 3-weekly T/FEC and trastuzumab (61% and 65%, respectively). However, in HR-positive patients, higher pCR rates were achieved with 3-weekly T/FEC and trastuzumab (47%) than with the weekly T/FAC (25%; p=0.04) or 3-weekly T/FAC (19%; p=0.01) ( Table 1 ). Near pCR (RCB-I) was slightly higher in HR-positive (26%) than in HR-negative patients treated with 3-weekly T/FEC and trastuzumab (11%; p=0.07). Conclusions: Patients with HR- negative/HER2-positive breast cancer had similar pathologic response rates from addition of trastuzumab to 3-weekly T/FEC or from weekly T/FAC chemotherapy. Patients with HR-positive/HER2-positive breast cancer obtained significant benefit from addition of trastuzumab to 3- weekly T/FEC, compared to 3-weekly T/FAC or weekly T/FAC. The combination of weekly T/FEC with trastuzumab as neoadjuvant chemotherapy should be evaluated.

[Table: see text]

[Table: see text]

Inclusion of taxanes, particularly weekly paclitaxel, in preoperative chemotherapy improves pathologic complete response rate in estrogen receptor-positive breast cancers

BACKGROUND

We examined if inclusion of a taxane and more prolonged preoperative chemotherapy improves pathologic complete response (pCR) rate in estrogen receptor (ER)-positive breast cancer compared with three to four courses of 5-fluorouracil, doxorubicin, cyclophosphamide (FAC).

PATIENTS AND METHODS

Pooled analysis of results from seven consecutive neo-adjuvant chemotherapy trials including 1079 patients was carried out. These studies were conducted at MD Anderson Cancer Center from 1974 to 2001. Four hundred and twenty-six (39.5%) patients received taxane-based neo-adjuvant therapy. pCR rates and survival times were analyzed as a function of chemotherapy regimen and ER status. Multivariate logistic and Cox regression analysis were carried out to identify variables associated with pCR and survival.

RESULTS

Patients with ER-negative cancer had higher overall pCR rate than patients with ER-positive tumors (20.1% versus 4.9%, P < 0.001). In ER-negative patients, the pCR rates were 29% and 15% with and without a taxane (P < 0.001). In ER-positive patients, the pCR rates were 8.8% and 2.0% with and without a taxane (P < 0.001). In multivariate analysis, clinical tumor size (P < 0.001), ER-negative status (P < 0.001) and inclusion of a taxane (P = 0.01) were independently associated with pCR. For patients with pCR, survival was similar regardless of ER status or the type of regimen that induced pCR.

CONCLUSION

pCR rates increased for patients with both ER-positive and ER-negative tumors as regimens started to include a taxane and became longer. This indicates that a subset of patients with ER-positive breast cancer benefits from more aggressive chemotherapy, similarly to patients with ER-negative tumors.

Two year analysis of treatment efficacy and cosmesis by the American Society of Breast Surgeons (ASBS) MammoSite Breast Brachytherapy Registry Trial in patients treated with accelerated partial breast irradiation (APBI)

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Background: This report presents 2-year data on treatment efficacy and cosmesis for patients enrolled on the ASBS sponsored MammoSite Registry trial. Methods: 1449 patients were treated with the MammoSite device to deliver APBI. 924 patients have been followed ≥ 12 months, 586 ≥ 18 months, 316 ≥ 24 months and 52 ≥ 36 months. Median follow-up for surviving patients was 14 months. Results: Eleven patients (0.8%) developed an ipsilateral breast tumor recurrence (IBTR) as some component of their initial failure (prior to distant metastases [DM]) for a 2-yr actuarial rate of 1.2%. The 2-yr actuarial rate of isolated IBTR was 0.8% (n=8). Six patients (0.4%) developed an axillary failure (AF) as some component of their initial failure (prior to DM) for a 2-yr actuarial rate of 1.0%. The 2-yr actuarial rate of isolated AF was 0.6% (n=3). The only variable associated with the development of an isolated IBTR (n=8) included an extensive intraductal component (p=0.073) (patient age, margin status, grade, histology, tumor size, nodal status, use of systemic therapy and method of device placement were not associated with IBTR). The only variable associated with the development of all IBTRs (n=11) was tumor location (inner quadrant, p=0.079). The percentage of patients with good/excellent cosmetic results at 6, 12, 18, 24 and 36 months were as follows: 95.1% (n=769 patients), 93.7% (n=621 patients), 91.3% (n=344 patients), 93.5% (n=248 patients), and 90.4% (n=52 patients) (p=NS). For the 174 patients with both a 12-month and 24 month cosmetic assessment, the rate of good/excellent cosmetic results was 94% at 12 and 24 months. At 24 months (n=248 patients), factors associated with good/excellent cosmetic results included increased skin spacing as a categorical variable (94.8% versus 86.1%, p=0.064), no infection (94.8% versus 85.7%, p=0.057), and no systemic chemotherapy treatment (95.3% versus 82.4%, p=0.012). Conclusions: Treatment efficacy and cosmesis 2 years after treatment with APBI using the MammoSite device are excellent and appear similar to those reported with standard whole breast RT.

No significant financial relationships to disclose.

A new measurement of residual cancer burden to predict survival after neoadjuvant chemotherapy

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Background: The strength of association between tumor response and survival is critical for neoadjuvant chemotherapy trials. Pathologic complete response (pCR) reliably predicts survival benefit, but residual disease contains a range of pathologic responses that likely contain different prognostic groups, including near complete response and resistance. Methods: Pathologic slides and reports were reviewed from 432 patients in two completed neoadjuvant trials: 1) fluorouracil, doxorubicin and cyclophosphamide (FAC) in 189 patients, and 2) paclitaxel followed by FAC (T/FAC) in 243 patients. Paclitaxel was administered as twelve weekly (n=126) or four 3-weekly cycles (n=117). Residual cancer burden (RCB) was calculated as an index that combines pathologic measurements of primary tumor (size and cellularity) and nodal metastases (number and size). We compared four RCB categories, from RCB-0 (pCR) to RCB-3 (chemoresistant), and post-treatment revised AJCC Stage (0-III) for prediction of distant relapse-free survival (DRFS) in multivariate Cox regression analyses (stratified by ER status). Results: The pCR rate was greater after T/FAC than FAC (24% vs. 16%, LR p<0.05), and after weekly (vs. 3-weekly) paclitaxel in T/FAC (30% vs. 16%, LR p<0.01). In patients with residual disease, RCB measurements were significantly lower after T/FAC than FAC (t-test, p<0.0001), but were not different between paclitaxel schedules in T/FAC. RCB was a continuous predictor of DRFS after T/FAC (HR=1.86, 95%CI 1.51–2.30) or FAC (HR=1.67, CI 1.38–2.01) with median follow-up 5 and 8 years, respectively. The resistant category RCB-3 predicted relapse more strongly than AJCC Stage III and identified a larger group of high-risk patients ( Table ). Conclusions: RCB is a new continuous measure of pathologic response that is defined from routine pathologic materials, represents the distribution of residual disease, is a significant predictor of DRFS, and defines chemotherapy resistance more effectively than revised AJCC Stage.

[Table: see text]

[Table: see text]

Meta-analysis of sentinel lymph node biopsy after preoperative chemotherapy in patients with breast cancer

BACKGROUND

Women with breast cancer are more frequently being treated with preoperative neoadjuvant chemotherapy. The reliability of sentinel lymph node biopsy (SLNB) following chemotherapy has not been determined. This was a meta-analysis of studies that examined the results of SLNB after preoperative chemotherapy.

METHODS

Included articles had to meet two criteria. First, patients had to have had operable breast cancer and to have undergone SLNB after preoperative chemotherapy and, second, patients had to have undergone subsequent axillary lymph node dissection. Meta-analyses were performed in which Bayesian hierarchical models were created to estimate the identification rate (IR) and sensitivity of SLNB in this setting.

RESULTS

Twenty-one studies were identified that included a total of 1273 patients. The IRs reported ranged from 72 to 100 per cent, with a pooled estimate of 90 per cent. The sensitivity of SLNB ranged from 67 to 100 per cent, with a pooled estimate of 88 (95 per cent confidence interval 85 to 90) per cent. Meta-analyses performed using Bayesian modelling resulted in (posterior) estimates for IR and sensitivity of 91 (95 per cent credible interval 88 to 94) and 88 (95 per cent credible interval 84 to 91) per cent respectively.

CONCLUSION

SLNB is a reliable tool for planning treatment after preoperative chemotherapy.

A single-gene biomarker identifies breast cancers associated with immature cell type and short duration of prior breastfeeding

The pathogenesis of breast cancers that do not express estrogen receptors or Her-2/neu receptors (ER-/HER2- phenotype) is incompletely understood. We had observed markedly elevated gene expression of gamma-aminobutyric acid type A (GABA(A)) receptor subunit pi (GABApi, GABRP) in some breast cancers with ER-/HER2- phenotype. In this study, transcriptional profiles (TxPs) were obtained from 82 primary invasive breast cancers by oligonucleotide microarrays. Real-time reverse transcription-polymerase chain reaction (RT-PCR) was used to measure GABApi gene expression in a separate cohort of 121 invasive breast cancers. GABApi gene expression values from TxP and RT-PCR were standardized and compared with clinicopathologic characteristics in the 203 patients. GABApi gene expression was increased in 16% of breast cancers (13/82 TxP, 20/ 121 RT-PCR), particularly in breast cancers with ER-/HER2- phenotype (60%), and breast cancers with basal-like genomic profile (60%). The profile of genes coexpressed with GABApi in these tumors was consistent with an immature cell type. In multivariate linear regression analysis, the level of GABApi gene expression was associated with ER-/HER2- phenotype (P < 0.0001), younger age at diagnosis (P = 0.0003), and shorter lifetime duration of breastfeeding (< or = 6 months) in all women (P = 0.017) and specifically in parous women (P = 0.013). GABApi gene expression was also associated with combinations of high grade with ER-/HER2- phenotype (P = 0.002), and with Hispanic ethnicity (P = 0.036). GABApi gene expression is increased in breast cancers of immature (undifferentiated) cell type and is significantly associated with shorter lifetime history of breastfeeding and with high-grade breast cancer in Hispanic women.

First analysis of patient demographics, technical reproducibility, cosmesis, and early toxicity

BACKGROUND

Eighty-seven institutions participated in a Registry Trial that was designed to collect data on the clinical use of the MammoSite breast brachytherapy catheter for delivering breast irradiation. Patient demographics, technical reproducibility, cosmesis, and early toxicity were evaluated.

METHODS

From May 4, 2002 through July 30, 2004, 1419 patients with Stage 0, I, or II breast carcinoma who were undergoing breast-conserving therapy were enrolled on the trial. The device was placed in 1403 of these patients. The 1237 patients (87% of enrolled patients) who received accelerated partial breast irradiation (APBI) (34 grays prescribed to 1.0 cm in 10 fractions; 95% of patients who received APBI) constituted the study population; 86% of those patients (1068) had Stages I-II breast carcinoma (median tumor size, 10 mm), and 14% of those patients (169) had Stage 0 breast carcinoma. Ninety-one percent of the patients with invasive carcinoma (977 of 1068 patients) had negative lymph node status, and 99% of all patients had negative margins. The median patient age was 65 years. Systemic chemotherapy alone was administered to 79 patients with invasive carcinoma (7%), hormone therapy was administered to 501 patients (45%), and both were administered to 39 patients (4%). The median follow-up was 5 months.

RESULTS

Five hundred fifty-four catheters (45%) were placed with an open cavity at the time of lumpectomy, and 683 catheters (55%) were placed with a closed cavity after lumpectomy. Skin spacing ranged from 2 mm to 75 mm (median, 10 mm). In 89% of patients, there was a minimum balloon-to-skin distance of 7 mm (2% of patients had distances < 5 mm). In terms of cosmetic assessment, 95% of patients (1030 of 1084 patients) who had a cosmetic assessment had a good/excellent result (last follow-up visit). Cosmetic results at 12 months were good/excellent in 92% of 248 evaluable patients. The median skin spacing (> or = 7 mm vs. < 7 mm) was associated significantly with a good/excellent cosmetic result (96.1% vs. 86.8%; P = 0.0001) overall and at 6 months (P = 0.006). Increasing skin spacing was associated with a good/excellent cosmetic result as a continuous variable (P < 0.0001). In total, 92 of 1140 evaluable patients (8.1%) developed an infection in the breast, which was device-related in 5.3% of patients (60 of 1140 patients). Good/excellent cosmetic results were noted in 86% of these patients (last follow-up visit). Fifteen of 442 evaluable patients (3.4%) developed a radiation recall reaction. Good/excellent cosmetic results were noted in 93% of these patients at their last follow-up visit. One local recurrence (0.1%) was reported (new primary carcinoma).

CONCLUSIONS

Clinical evaluation of the ability of the MammoSite breast brachytherapy catheter to deliver APBI demonstrated acceptable technical reproducibility between multiple institutions and use in appropriate groups of patients. Cosmetic results at 12 months (92% good/excellent) were comparable to those reported with whole-breast RT. Early toxicity rates (infections, radiation recall) appeared to be acceptable.