Nayana Dekhne

Differences in patterns of failure in patients treated with accelerated partial breast irradiation versus whole-breast irradiation: a matched-pair analysis with 10-year follow-up.

PURPOSE To examine 10-year results of a single institutions experience with radiotherapy limited to the region of the tumor bed (i.e., accelerated partial breast irradiation, [APBI]) in selected patients treated with breast-conserving therapy (BCT) and compare them with results of matched BCT patients who underwent whole-breast irradiation (WBI). PATIENTS AND METHODS A total of 199 patients with early-stage breast cancer were treated prospectively with BCT and APBI using interstitial brachytherapy. To compare potential differences in local recurrence rates on the basis of the volume of breast tissue irradiated, patients in the APBI group were matched with 199 patients treated with WBI. Match criteria included tumor size, nodal status, age at diagnosis, margins of excision, estrogen receptor status, and use of adjuvant tamoxifen therapy. Local-regional control, disease-free survival, and overall survival were analyzed between treatment groups. RESULTS Median follow-up for surviving patients was 9.6 years (range, 0.3-13.6 years). Eight ipsilateral breast tumor recurrences (IBTRs) were observed in patients treated with APBI. The cumulative incidence of IBTR at 10 years was 5%. On matched-pair analysis, the rate of IBTR was not statistically significantly different between the patient groups (4%, 95% confidence interval [CI] 1.3-6.7% for WBI therapy patients vs. 5%, 95% CI 1.5-8.5% for APBI patients; p = 0.48). CONCLUSIONS Radiation therapy limited to the region of the tumor bed (APBI) produced 10-year local control rates comparable to those from WBI in selected low-risk patients.

Molecular classification system identifies invasive breast carcinoma patients who are most likely and those who are least likely to achieve a complete pathologic response after neoadjuvant chemotherapy

The molecular classification system categorizes invasive breast carcinomas according to their key driving biomarkers. In the current study, the authors evaluated whether response to neoadjuvant chemotherapy was correlated with the molecular classification groups.

Failure rate and cosmesis of immediate tissue expander/implant breast reconstruction after postmastectomy irradiation

BACKGROUND This study reports the rate of breast reconstruction failure and cosmetic outcomes after postmastectomy radiation therapy (PMRT) with temporary tissue expanders (TEs) or implants in place. PATIENTS AND METHODS Ninety-four patients underwent mastectomy (93 unilateral, 1 bilateral; 95 cases total) and immediate TE reconstruction followed by PMRT. Ninety TEs and 5 permanent implants were irradiated. All patients received a dose of 5400 cGy given in 180-cGy fractions to the reconstructed breast. Twenty-one patients (22%) received tangents alone and 74 patients (78%) were treated with tangents and a supraclavicular field using a monoisocentric technique. Bolus was used in 91 patients (96%). Eighty-eight patients (93%) received chemotherapy and 78 patients (82%) received endocrine therapy. RESULTS With a median follow-up of 24.1 months, 19 patients (20%) experienced failure of reconstruction. The 1-, 2-, and 3-year actuarial rate of reconstruction failure was 9.7%, 19.3%, and 25.5%, respectively. Infection was the most common cause of failure. Of the 19 failures, 8 patients underwent salvage procedures with flap reconstruction. Univariate analysis was performed examining age, chemotherapy use, hormone therapy use, use of a supraclavicular field, smoking status, diabetes, hypertension, and menopausal status. No risk factors were found to be associated with reconstruction failure. In patients who did not experience reconstruction failure, good/excellent cosmesis was observed in 75% of patients. CONCLUSION In the current series of women with a high risk of locoregional recurrence, PMRT with a TE/implant in place provides good cosmesis in the majority of women, with an acceptable risk of expander or implant loss.

Differences in disease presentation, management techniques, treatment outcome, and toxicities in African-American women with early stage breast cancer treated with breast-conserving therapy.

Data on patients who received breast‐conserving therapy (BCT) for early stage breast cancer were examined to detect differences in disease presentation, management techniques, long‐term treatment outcomes, and toxicities based on race.

Comparison of lymphedema in patients with axillary lymph node dissections to those with sentinel lymph node biopsy followed by immediate and delayed ALND.

Purpose:The purpose of the study was to show that delayed axillary lymph node dissection (ALND) has higher rates of lymphedema compared with immediate ALND, using data from NSABP-B32 at Beaumont Hospital. Method:NSABP B-32 at Beaumont had 207 patients with follow-up data on 199 patients, randomizing clinically negative axilla to sentinel lymph node biopsy (SLNB)+ALND (GrA N=98), and SLNB+cytology±ALND (GrB N=101). All patients had preoperative volumetric arm measurements and only node negatives had routine postoperative measurements assessing lymphedema for 36 months. We contacted node-positive patients for postoperative measurements for this study. Twenty-four and 15 cytology-positive patients had SLNB+ALND in GrA and GrB, respectively (SubGrA1 N=24; SubGrB1 N=15). Fourteen hematoxylin and eosin-positive patients had delayed ALND (SubGrB2a N=14). Results:Lymphedema rate for node-positive SLNB+ALND was 10.3% [SubGrA1 (3/24)+SubGrB1 (1/15)=4/39] and node-negative SLNB+ALND was 6.8% (SubGrA2=5/74). Lymphedema was 14.3% for delayed ALND in SubGrB2a (2 of 14) and 0% for 72 SLNBs in SubGrB2b. Our study comparing immediate and delayed ALND lymphedema was not statistically significant (10.3% vs. 14.3%, P=0.65). Comparing node-negative ALND (SubGrA2= 5/74=6.8%) to node-positive ALND (A1+B1+B2a=6/53=11.3%) was not statistically significant (P=0.52). Comparing lymphedema for node-negative ALND (SubGrA2) to SLNB (SubGrB2b) only approached significance (6.8% vs. 0%, P=0.058). Conclusions:The rate of lymphedema was higher in delayed ALND but not statistically significant. Comparison, however, is difficult, given the limited sample size. We urge the other centers of NSABP-B32 to validate this, by contacting the node-positive patients for measurements. The lymphedema rate for SLNB alone was 0% and approached statistical significance when compared with node-negative ALND.

Impact of lymph node status on clinical outcomes after accelerated partial breast irradiation

PURPOSE To compare outcomes after accelerated partial breast irradiation (APBI) between node-negative and node-positive patients. METHODS AND MATERIALS A total of 534 patients with early-stage breast cancer received APBI including 39 node-positive (N+) cases. Clinical, pathologic, and treatment-related factors were compared between node-negative (N-) and N+ cohorts. Local recurrence (LR), regional recurrence (RR), axillary failure (AF), distant metastases (DM), disease-free survival (DFS), cause-specific survival (CSS), and overall survival (OS) were analyzed. RESULTS N+ patients were younger (p = 0.04), had larger tumors (p < 0.001), and were more likely to receive chemotherapy (p < 0.001). Mean follow-up was 7.8 years for N+ patients and 6.3 years for N- patients (p = 0.06). No differences were seen in 5-year actuarial rates of LR (2.2% vs. 2.6%, p = 0.86), AF (0% vs. 0%, p = 0.69), DFS (90.0% vs. 88.0%, p = 0.79), or OS (91.0 vs. 84.0%, p = 0.65) between the two groups, whereas higher rates of RR (0% vs. 6.1%, p < 0.001) and DM (2.2% vs. 8.9%, p = 0.005) were noted in N+ patients. A trend for improved CSS (p = 0.06), was seen in N- patients. Age, tumor size, receptor status, T-stage, chemotherapy, APBI technique, and nodal status (p = 0.86) were not associated with LR, while a trend for an association with LR was noted with close/positive margins, (p = 0.07), and failure to receive adjuvant hormonal therapy (p = 0.06). CONCLUSIONS No differences were seen in the rates of LR or AF between N- and N+ patients after APBI. These results support the continued enrollment of node-positive patients in Phase III trials evaluating the efficacy of APBI including the National Surgical Adjuvant Breast and Bowel Project-B39/Radiation Therapy Oncology Group 0413.

Mutational landscape of radiation-associated angiosarcoma of the breast

Purpose Radiation-associated breast angiosarcomas are a rare complication of radiation therapy for breast carcinoma. With relatively little is known about the genetic abnormalities present in these secondary tumors, we examined genomic variation in biospecimens from radiation-associated breast angiosarcomas. Experimental Design Patients were identified that had a previous breast cancer diagnosis, received radiation therapy, and developed angiosarcoma in the ipsilateral breast as the earlier cancer. Tumor regions were isolated from archival blocks using subsequent laser capture microdissection. Next generation sequencing was performed using a targeted panel of 160 cancer-related genes. Genomic variants were identified for mutation and trinucleotide-based mutational signature analysis. Results 44 variants in 34 genes were found in more than two thirds of the cases; this included 12 variants identified as potentially deleterious. Of particular note, the BRCA1 DNA damage response pathway was highly enriched with genetic variation. In a comparison to local recurrences, 14 variants in 11 genes were present in both the primary and recurrent lesions including variants in genes associated with the DNA damage response machinery. Furthermore, the mutational signature analysis shows that a previously defined IR signature is present in almost all of the current samples characterized by predominantly C→T substitutions. Conclusions While radiation-associated breast angiosarcomas are relatively uncommon, their prognosis is very poor. These data demonstrate a mutational pattern associated with genes involved in DNA repair. While important in revealing the biology behind these tumors, it may also suggest new treatment strategies that will prove successful.

Surgical decisions of newly diagnosed breast cancer patients following genetic referral.

40 Background: In response to many recent publications and mandates to assure referrals to genetic counseling for oncology patients, the Royal Oak (RO) Breast Care Center (BCC) at Beaumont Health System (BHS) evaluated the surgical outcomes of genetic referral(GR) in breast cancer (BC) patients. The goal of this study was to determine the impact of GR on surgical decision making and evaluate outcomes in this population. METHODS A retrospective chart review was performed, to identify patients who had a BC diagnosis and met criteria for GR from July 2012- July 2014. Age, histology, laterality of cancer, prior history of cancer, neoadjuvant chemotherapy, plastic surgery consultation, MRI, reason for MRI, additional testing, type of surgery, laterality of surgery, reconstruction, lymph node surgery, and time from diagnosis to surgery were evaluated using Chi Square analysis. RESULTS A total of 506 patients with a new BC diagnosis seen at the RO BCC at BHS within the inclusion dates were analyzed. There were 191 patients referred to the GP for counseling and possible genetic testing. Eighty percent of the referred patients underwent genetic testing. Twelve patients tested positive for deleterious mutations in BRCA 1 or 2. A statistically significant difference was found in the BC patients referred to the GP with respect to age, MRI usage, neoadjuvant chemotherapy, type and laterality of surgery, ALND, plastic surgery consult & reconstruction, and time from diagnosis to surgery. MRI usage in patients referred to GP was 43.5% vs. 12.7% in those not referred. Mastectomy rate in patients referred to GP was 51.3% vs. 25.5% (p<0.001) in those not referred. Bilateral mastectomy was 30.9% vs. 5.8% (p<0.001). CONCLUSIONS We have found that patients referred to the GP have increased the use of MRI testing, which in itself has been shown to increase mastectomy rates. We also identified a trend in these patients toward bilateral mastectomy. According to our outcomes, there are multiple possible reasons for this trend, including family history, physician bias, stage at diagnosis, age and factors intrinsic to the patient. Furthermore, a multivariate analysis is needed to assess the relationship between a GR and a patients surgical decision.

Accelerated partial-breast irradiation (APBI) versus whole-breast irradiation (WBI) in treatment of the biological subtypes of breast cancer: An analysis of comparative effectiveness.

45 Background: To assess if partial vs whole breast irradiation (RT) in treatment of the various biological (bio-) subtypes of breast cancer would lead to differing clinical results, a match pair analysis of APBI vs WBI was undertaken. METHODS Between 3/1993 and 9/2013 all breast CA patients (pts) treated at one institute with either APBI or WBI were matched 1:1 by follow-up (FU) +/- 15 yrs, stage and bio-subtype. This yielded 772 pts of whom 640 were luminal A, 42 luminal B, 58 triple neg (TNBC), 6 HER2+, and 26 triple +. Outcomes were analyzed across the various bio-subtypes for all the pts (APBI + WBI), APBI alone and WBI alone. The endpoints assessed were local recurrence (LR), true recurrence/marginal miss (TR/MM), elsewhere failure (EF), regional recurrence (RR), distant metastasis (DM), disease-free survival (DFS), and contralateral breast failure (CLBF). RESULTS Mean age was 66 (32-94) with a mean FU of 5.2 years (0.1-18.3). Regarding systemic therapy, 75% received endocrine Rx, while chemotherapy was documented in 21%. For all pts (APBI+WBI) there was no significant difference across the various bio-subtypes with respect to 5, 10 and 15 yr actuarial LR, TR/MM, EF, RR, DM, DFS and CLBF. Likewise, for the 386 APBI-alone treated pts, no significant difference was found between the various bio-subtypes for all the same endpoints reported. However, for the 386 WBI pts, a significant difference was seen in the 15-year actuarial LR between luminal A and TNBC (1.5% vs 7.4%, p = 0.007). Significance was also found in the 15-year actuarial DFS between luminal A/B and TNBC (98.0%, 95.2%; 86.0%, respectively, p = 0.009). CONCLUSIONS In comparing partial to whole breast RT across the various biological subtypes of breast CA, APBI is at least as effective as WBI. However, the retrospective nature of this study along with the limited numbers of pts in the HER2+ and triple + subsets are weaknesses which are acknowledged to exist in this dataset. The addition of further pts in all the biological subtypes, particularly the HER2+ and triple + subsets, along with results from randomized trials incorporating biomarker data will be needed to substantiate these findings.

Clinical efficacy of accelerated partial-breast irradiation in treatment of ER-negative breast cancer: Results of a matched pair analysis.

70 Background: To assess outcomes of ER-negative breast CA pts treated with APBI, a matched-pair analysis was performed to determine efficacy of APBI vs whole breast RT (WBRT) from a single institution. METHODS From over 1650 pts treated with BCT from 1980-2013, a cohort of ER[-] pts treated with APBI or WBRT were investigated. Matched-pair analysis with a 1:1 ratio paired 79 APBI with 79 WBRT pts, all ER[-] (total:158). Match criteria included follow-up (FU) > 1.0 yr, stage, & age +/- 5 yrs. Outcomes analyzed included local recurrence (LR), true recurrence/marginal miss (TRMM), regional recurrence (RR), distant metastases (DM), disease-free (DFS), cause-specific (CSS), and overall survivals (OS). RESULTS As for clinical-pathological traits, no significant differences were noted for age (p=0.302), T-stage (p=1.000), tumor size (p=0.721), N-stage (p=0.062), use of chemoRx (p=0.747), endocrine Rx(p=0.408) or Herceptin (p=1.00). Per ASTRO Guidelines, no differences were seen in cautionary or unsuitable [UnS] groups between APBI & WBRT (p=0.333). With a mean FU of 8.0 yrs (10.1 yrs APBI; 8.4 yrs WBRT p<0.001), no differences were seen in the 10-yr actuarial rates of LR (9.3% vs 22.1% p=0.094), RR (1.3% vs 8.1% p=0.299), DM (7.1% vs 13.0% p=0.429), DFS (83.9% vs. 72.5% p=0.214), CSS (93.5% vs. 89.0 % p=0.677), or OS (79.6% vs. 80.1% p=0.573) between APBI & WBRT. Only TRMM was significantly different (0% APBI vs 12.5% p=0.011). In stratifying patients based on ER% (0%, 1-3%, 4-8%) no outcome differences were noted. Of the 158 ER[-] pts, 124 were cautionary with similar 10-yr outcomes except for TRMM (0% APBI;WBRT 14.4% p=0.017) & CLBF (0% APBI;WBRT17.1% p=0.019). For the 34 UnS patients, no endpoint differences were seen APBI vs WBRT. But, when the entire 158 ER[-] patients were analyzed for # of UnS factors, increasing UnS factors led to significant risk of RR (p<0.001) & DM (p=0.002). CONCLUSIONS With 10-year FU of APBI for ER[-], the clinical results were equivalent to WBRT. No differences were noted based on ER%. Increasing number of unsuitable factors had more RR and DM. Maturation of randomized trial data will be needed to provide Class I evidence for equivalence of APBI to WBRT in ER[-] patients.