Patient-Reported Outcomes in Patients Undergoing Lumpectomy With and Without Defect Closure.

BACKGROUND: The effect of lumpectomy defect repair (a level 1 oncoplastic technique) on patient-reported breast satisfaction among patients undergoing lumpectomy has not yet been investigated. METHODS: Patients undergoing lumpectomy at our institution between 2018 and 2020 with or without repair of their lumpectomy defect during index operation, comprised our study population. The BREAST-Q quality-of-life questionnaire was administered preoperatively, and at 6 months, 1 year, and 2 years postoperatively. Satisfaction and quality-of-life domains were compared between those who did and did not have closure of their lumpectomy defect, and compared with surgeon-reported outcomes. RESULTS: A total of 487 patients met eligibility criteria, 206 (42%) had their partial mastectomy defect repaired by glandular displacement. Median breast volume, as calculated from the mammogram, was smaller in patients undergoing defect closure (826 cm3 vs. 895 cm3, p = 0.006). There were no statistically significant differences in satisfaction with breasts (SABTR), physical well-being of the chest (PWB-CHEST), or psychosocial well-being (PsychWB) scores between the two cohorts at any time point. While patients undergoing defect closure had significantly higher sexual well-being (SexWB) scores compared with no closure (66 vs. 59, p = 0.021), there were no predictors of improvement in SexWB scores over time on multivariable analysis. Patients' self-reported scores positively correlated with physician-reported outcomes. CONCLUSIONS: Despite a larger lumpectomy-to-breast volume ratio among patients undergoing defect repair, satisfaction was equivalent among those whose defects were or were not repaired at 2 years postsurgery. Defect repair was associated with clinically relevant improvement in patient-reported sexual well-being.

Examining Race and Patient-Reported Outcomes After Contralateral Prophylactic Mastectomy with Reconstruction.

BACKGROUND: Little is known regarding racial differences in satisfaction and quality of life (QOL) after contralateral prophylactic mastectomy (CPM). In this study, we aim to characterize associations between race, and postoperative satisfaction and well-being, utilizing the validated BREAST-Q patient-reported outcome measure. PATIENTS AND METHODS: Patients were eligible if they were diagnosed with stage 0-III unilateral breast cancer and underwent mastectomy with immediate reconstruction at our institution between 2016 and 2022. BREAST-Q surveys were administered in routine clinical care preoperatively and postoperatively to assess QOL. We assessed whether the relationship between race, and domains of satisfaction with breasts and psychosocial well-being differed by receipt of CPM compared with unilateral mastectomy at 6 months, 1 year, 2 years, and 3 years following reconstruction. RESULTS: Of 3334 women, 2040 (61%) underwent unilateral mastectomy and 1294 (39%) underwent CPM. Compared with White and Asian women who received CPM, Black women who underwent CPM were more likely to have higher BMI (p < 0.001), undergo autologous reconstruction (p = 0.006), and receive postmastectomy radiation (PMRT) (p < 0.001). There was no association between race and domains of satisfaction of breasts or psychosocial well-being for women who underwent unilateral mastectomy (p = 0.6 and p > 0.9, respectively) or CPM (p = 0.8 and p = 0.9, respectively). PMRT was negatively associated with both satisfaction with breasts (p < 0.001) and psychosocial well-being (p = 0.007). CONCLUSIONS: Differences in satisfaction with breasts and psychosocial well-being at 3-year follow-up were not associated with race but rather treatment variables, particularly the receipt of PMRT. Further investigations with a larger and more diverse population are needed to validate these findings.

Do HER2-Low Tumors Have a Distinct Clinicopathologic Phenotype?

BACKGROUND: Breast cancer subtypes, distinguished by hormone receptor (HR) and HER2 status, have different clinicopathologic features. With recognition of the clinical relevance of HER2-low, there is debate as to whether this is a distinct subtype. Our study aimed to determine whether HER2-low breast cancers have specific clinicopathologic features that differ from those of HER2-negative and HER2-positive cancers. PATIENTS AND METHODS: A total of 11,072 patients undergoing upfront surgery from 1998 to 2010 were identified from a single-institution prospectively maintained database. HER2 status was classified by immunohistochemistry (IHC)/fluorescence in situ hybridization (FISH) as HER2 negative (41.2%), HER2 low (45%; IHC 1+ or 2+ with negative FISH), and HER2 positive (13.7%), and stratified by HR status. Univariate (UVA) and multivariable multinomial logistic regression analysis (MVA) were performed to determine associations among variables and subtypes. RESULTS: Compared with HER2-negative tumors, HER2 low was associated with lymphovascular invasion [odds ratio (OR) 1.2, 95% confidence interval (CI) 1.06-1.36; p = 0.003], multifocality (OR 1.26, 95% CI 1.12-1.42; p < 0.001), nodal micrometastasis (OR 1.15, 95% CI 1.02-1.31; p = 0.024), and lower rates of ≥ 3 positive nodes (OR 0.77, 95% CI 0.66-0.90, p = 0.001). When stratified by HR expression, in both HR-positive and HR-negative tumors, age and multifocality were associated with HER2 low on UVA. On MVA, no variables were independently associated with both HR-negative and HR-positive/HER2-low tumors compared with HER2-negative tumors. In contrast, HER2-positive tumors, regardless of HR status, were associated with multifocality and an extensive intraductal component. CONCLUSION: Clinicopathologic features of HER2-low tumors appear to be primarily related to HR status. Our findings do not support the characterization of HER2 low as a separate subtype.

Satisfaction and Well-Being After Contralateral Prophylactic Mastectomy Among BRCA Mutation Carriers and Noncarriers: A Longitudinal Analysis of BREAST-Q Domains.

INTRODUCTION: Contralateral prophylactic mastectomy (CPM) is recommended for BRCA mutation carriers; its use in noncarriers relies on patient choice. We characterized differences in satisfaction and well-being after CPM between BRCA carriers and noncarriers. METHODS: BREAST-Q data were obtained before and after CPM with immediate reconstruction performed at a single institution from 2016 to 2022. Associations between BRCA status and satisfaction with breasts, psychosocial well-being, and sexual well-being were assessed, with adjustment for preoperative scores and relevant confounders. RESULTS: In total, 149 BRCA carriers and 842 noncarriers were included. Response rates varied over time (preoperative, 56%; 6 months, 78%; 1 year, 51%; 2 years, 52%; 3 years, 59%). BRCA carriers were younger (p < 0.001), with a higher rate of neoadjuvant chemotherapy (p < 0.001). More noncarriers had HR+/HER2- tumors (p < 0.001) and underwent endocrine therapy (p < 0.001). Baseline satisfaction with breasts was higher among BRCA carriers (median [interquartile range] score, 70 [53-82] vs. 58 [48-70]; p = 0.006); psychosocial (p = 0.20) and sexual (p = 0.14) well-being were not significantly different between groups. BRCA carriers had a greater decrease in satisfaction with breasts (p = 0.04) and psychological well-being (p = 0.05) from baseline to 6 months; decrease in sexual well-being (p = 0.38) was not significantly different between groups. On univariate and multivariable analyses, BRCA status was not associated with satisfaction with breasts, sexual well-being, or psychosocial well-being. CONCLUSIONS: Satisfaction and well-being were similar between BRCA carriers and noncarriers treated with CPM. Relative to noncarriers, BRCA carriers experienced a greater decline in satisfaction with breasts and psychological well-being at 6 months after CPM.

Strategies to avoid mastectomy skin-flap necrosis during nipple-sparing mastectomy.

BACKGROUND: Nipple-sparing mastectomy is associated with a higher risk of mastectomy skin-flap necrosis than conventional skin-sparing mastectomy. There are limited prospective data examining modifiable intraoperative factors that contribute to skin-flap necrosis after nipple-sparing mastectomy. METHODS: Data on consecutive patients undergoing nipple-sparing mastectomy between April 2018 and December 2020 were recorded prospectively. Relevant intraoperative variables were documented by both breast and plastic surgeons at the time of surgery. The presence and extent of nipple and/or skin-flap necrosis was documented at the first postoperative visit. Necrosis treatment and outcome was documented at 8-10 weeks after surgery. The association of clinical and intraoperative variables with nipple and skin-flap necrosis was analysed, and significant variables were included in a multivariable logistic regression analysis with backward selection. RESULTS: Some 299 patients underwent 515 nipple-sparing mastectomies (54.8 per cent (282 of 515) prophylactic, 45.2 per cent therapeutic). Overall, 23.3 per cent of breasts (120 of 515) developed nipple or skin-flap necrosis; 45.8 per cent of these (55 of 120) had nipple necrosis only. Among 120 breasts with necrosis, 22.5 per cent had superficial, 60.8 per cent had partial, and 16.7 per cent had full-thickness necrosis. On multivariable logistic regression analysis, significant modifiable intraoperative predictors of necrosis included sacrificing the second intercostal perforator (P = 0.006), greater tissue expander fill volume (P < 0.001), and non-lateral inframammary fold incision placement (P = 0.003). CONCLUSION: Modifiable intraoperative factors that may decrease the likelihood of necrosis after nipple-sparing mastectomy include incision placement in the lateral inframammary fold, preserving the second intercostal perforating vessel, and minimizing tissue expander fill volume.

How Often Do Sentinel Lymph Node Biopsy Results Affect Adjuvant Therapy Decisions Among Postmenopausal Women with Early-Stage HR+/HER2- Breast Cancer in the Post-RxPONDER Era?

BACKGROUND: The RxPONDER trial reported no benefit to chemotherapy among postmenopausal patients with HR+/HER2- tumors, one to three positive nodes, and low recurrence scores, questioning the role of axillary staging in this population. Here, we evaluate the impact of sentinel lymph node biopsy (SLNB) results on adjuvant therapy decisions in postmenopausal women with HR+/HER2- breast cancer. PATIENTS AND METHODS: Postmenopausal women with cT1-2N0, HR+/HER2- breast cancer treated with lumpectomy and SLNB from 2012 to 2018 were identified. Receipt of nodal irradiation, indication for axillary lymph node dissection (ALND) and chemotherapy, and partial breast irradiation (PBI) eligibility were reviewed with pre- and post-SLNB results. RESULTS: A total of 1786 women were identified: median age 62 years, 84% with pT1 tumors, and 16% with pT2-3 tumors. Of those, 85% (n = 1525) remained pN0, 14% (n = 244) were pN1, and 1% (n = 17) were pN2-3. A total of 20 (1%) patients had > 2 positive SLNs, necessitating ALND. Pre-SLNB, 1478 women were considered PBI eligible; post-SLNB, 227 (13%) converted to PBI ineligible. In total, 58 patients with positive nodes received nodal irradiation, representing 3% of the entire cohort and 22% of pN+ patients. Overall, 1401 patients had an Oncotype DX recurrence score available, including 1273 patients with pN0 stage and 128 with pN1, with 173 (14%) and 16 (13%), respectively, having a recurrence score > 25, warranting chemotherapy. CONCLUSIONS: While few cN0 postmenopausal women with HR+/HER2- tumors had nodal pathology that warranted ALND, receipt of nodal irradiation, or indicated need for chemotherapy, in 13%, SLNB would have an impact on consideration for PBI. Among patients eligible for PBI, findings from SLNB may help refine selection among postmenopausal women with this tumor profile.

How Much Pain Will I Have After Surgery? A Preoperative Nomogram to Predict Acute Pain Following Mastectomy.

INTRODUCTION: Acute postoperative pain affects time to opioid cessation and quality of life, and is associated with chronic pain. Effective screening tools are needed to identify patients at increased risk of experiencing more severe acute postoperative pain, and who may benefit from multimodal analgesia and early pain management referral. In this study, we develop a nomogram to preoperatively identify patients at high risk of moderate-severe pain following mastectomy. METHODS: Demographic, psychosocial, and clinical variables were retrospectively assessed in 1195 consecutive patients who underwent mastectomy from January 2019 to December 2020 and had pain scores available from a post-discharge questionnaire. We examined pain severity on postoperative days 1-5, with moderate-severe pain as the outcome of interest. Multivariable logistic regression was performed to identify variables associated with moderate-severe pain in a training cohort of 956 patients. The final model was determined using the Akaike information criterion. A nomogram was constructed using this model, which also included a priori selected clinically relevant variables. Internal validation was performed in the remaining cohort of 239 patients. RESULTS: In the training cohort, 297 patients reported no-mild pain and 659 reported moderate-severe pain. High body mass index (p = 0.042), preoperative Distress Thermometer score ≥4 (p = 0.012), and bilateral surgery (p = 0.003) predicted moderate-severe pain. The resulting nomogram accurately predicted moderate-severe pain in the validation cohort (AUC =  0.735). CONCLUSIONS: This nomogram incorporates eight preoperative variables to provide a risk estimate of acute moderate-severe pain following mastectomy. Preoperative risk stratification can identify patients who may benefit from individually tailored perioperative pain management strategies and early postoperative interventions to treat pain and assist with opioid tapering.

Can We Successfully De-Escalate Axillary Surgery in Women Aged ≥ 70 Years with Ductal Carcinoma in Situ or Early-Stage Breast Cancer Undergoing Mastectomy?

BACKGROUND: Omission of sentinel lymph node biopsy (SLNB) in older women with clinically node-negative, hormone receptor-positive (HR+) early-stage breast cancer undergoing lumpectomy is accepted, given established low rates of regional recurrence. The safety of omitting SLNB in women undergoing mastectomy is unknown and may differ depending on extent of breast disease and variation in radiotherapy use. PATIENTS AND METHODS: From 2006 to 2018, 123 cTis and 328 cT1-2 HR+/HER2- tumors from 410 women aged ≥ 70 years who underwent mastectomy and SLNB were included (41 bilateral cases). The rate of nodal positivity and effect of nodal positivity on adjuvant therapy use were examined. RESULTS: Median age was 74 years; 21% of patients had positive sentinel lymph nodes, 7% had micrometastases, and 14% had macrometastases. Of cases of cTis tumors, 31% were upstaged to invasive carcinoma; 1% had macrometastases. Fewer cases of cT1 than cT2 tumors had macrometastases [13% (26/200) versus 29% (37/128); p < 0.001]. Eight percent of patients with pT1 tumors (18/228) and 27% of patients with pT2 tumors (30/113) received chemotherapy. Most patients with pT1, pN1 disease (78%; 25/32) did not receive chemotherapy. Rates of locoregional recurrence were similar between patients with cT1 or cT2 tumors with and without nodal metastases (median follow-up, 4.5 years). CONCLUSIONS: Women aged ≥ 70 years with cTis and cT1N0 HR+/HER2- tumors who underwent mastectomy had low rates of nodal positivity, similar to rates reported for lumpectomy. Given this and the RxPONDER results, omission of SLNB may be considered, as findings are unlikely to alter adjuvant therapy recommendations.

Is local recurrence higher among patients who downstage to breast conservation after neoadjuvant chemotherapy?

BACKGROUND: In early studies, local recurrence (LR) rates were higher after neoadjuvant chemotherapy (NAC) in comparison with upfront surgery. Modern outcomes are uncertain, particularly among those who are initially breast-conserving surgery-ineligible (BCSi) and downstage to being breast-conserving surgery-eligible (BCSe). METHODS: Among patients with cT1-3 breast cancer treated from 2014 to 2018 who were BCSe after NAC, clinicopathologic characteristics and LR were compared between initially BCSe patients and BCSi patients who downstaged. Breast-conserving surgery (BCS) eligibility was determined prospectively. RESULTS: Among 685 patients, 243 (35%) were BCSe before and after NAC and had BCS; 282 (41%) were BCSi before NAC, downstaged to BCSe, and had BCS; and 160 (23%) were BCSi before NAC, downstaged to BCSe, and chose mastectomy. The median age was 52 years, and most cancers were cT1-2 (84%), cN+ (61%), and human epidermal growth factor receptor 2-positive (HER2+; 38%) or triple-negative (34%). Those who were BCSe before NAC had a lower cT stage, whereas those who chose mastectomy were younger (P < .05). NAC was usually ACT (doxorubicin, cyclophosphamide, and a taxane)-based (92%), 99% of HER2+ patients received dual blockade, and 99% of BCS patients received adjuvant radiation. At a median follow-up of 35 months, 22 patients (3.2%) had developed LR. The Kaplan-Meier 4-year LR rates were not different among the groups (1.9% for those who were BCSe before and after NAC, 6.3% for those who downstaged to being BCSe and underwent BCS, and 2.7% for those who downstaged and underwent mastectomy; P = .17). CONCLUSIONS: LR rates are low after NAC and BCS, even among BCSi patients who downstage, and they are not improved in patients who downstage and choose mastectomy. Mastectomy can be safely avoided in BCSi patients who downstage with NAC.

Does preoperative MRI accurately stratify early-stage HER2 + breast cancer patients to upfront surgery vs neoadjuvant chemotherapy?

PURPOSE: HER2 +- amplified breast cancer patients derive benefit from treatment with anti-HER2-targeted therapy. Though adjuvant treatment is based on final pathology, decisions regarding neoadjuvant chemotherapy are made in the preoperative setting with imaging playing a key role in staging. We examined the accuracy of pre-operative imaging in determining pathological tumor size  (pT) in patients undergoing upfront surgery. METHODS: Early (cT1-T2N0) HER2 + breast cancer patients who underwent upfront surgery between 2015 and 2016 were identified from a prospective institutional database. We compared data for both clinical and final pathologic stage. Only those who underwent magnetic resonance imaging (MRI), mammography, and ultrasound in the preoperative setting were included in the analysis. Adjuvant treatment regimens were reviewed. RESULTS: We identified 87 cT1-2N0 patients with invasive HER2 + breast cancer who underwent upfront surgery. Median age was 52 years (IQR 43, 58) and median tumor size was 1.1 cm (IQR 0.5, 1.6). Fifteen patients (17%) were upstaged to stage II/III based on final pathology. Thirty-seven patients were T1cN0 on final pathology; 8 were cT1a-bN0 preop and 12 had pT overestimated by MRI by an average of 1.5 cm (> 0.5-1.5 cm). Compared to both mammography and MRI, the imaging modality most predictive of pT was ultrasound (p = 0.000072 ultrasound vs mammography and 0.000042 ultrasound vs MRI). CONCLUSION: For small HER2 + cN0 tumors undergoing upfront surgery, ultrasound was the imaging modality most predictive of pT. MRI overestimated tumor size in approximately 40% of patients. MRI may not accurately discriminate low-volume tumor burden in the breast and carries the potential of overtreatment in the upfront setting.

Reconstruction in Women with T4 Breast Cancer after Neoadjuvant Chemotherapy: When Is It Safe?

BACKGROUND: Despite limited evidence regarding its safety, immediate reconstruction (IR) is increasingly offered to women with T4 breast cancer. We compared outcomes after IR, delayed reconstruction (DR), and no reconstruction (NR) in patients treated with neoadjuvant chemotherapy (NAC) and postmastectomy radiation therapy (PMRT) for T4 disease. STUDY DESIGN: We retrospectively identified consecutive women with T4 tumors treated with trimodality therapy from January 2007 through December 2019. Clinicopathologic characteristics, complications requiring reoperation, time to PMRT, and recurrence patterns were compared. The cumulative incidence of local recurrence (LR) was estimated using Kaplan-Meier methods. RESULTS: Of the 269 women identified, the median (IQR) age was 52 (45-62) years; 164 women (61%) had T4d disease. Forty-five women (17%) had IR, 41 (15%) had DR, and 183 (68%) had NR. IR was independently associated with T4a-c disease (odds ratio [OR], 5.75; 95% CI, 2.57-12.87; p < 0.001) and younger age (OR 0.91; 95% CI, 0.86-0.94; p < 0.001). The risk of complications after IR was 22% overall and 46% in T4d patients (6/13), compared with 4.4% overall for NR and 7.3% for DR (p < 0.001). IR was associated with >8-week interval to PMRT (p < 0.001). At a median (range) follow-up of 4.2 (0.2-13) years, the median time to first recurrence was 18 months and was similar between groups (p = 0.13). The cumulative incidence of LR was 16% for T4d disease and 2.2% for T4a-c disease (p < 0.001). CONCLUSIONS: After IR, women with T4 tumors, particularly T4d disease, experienced delayed initiation of adjuvant treatment and substantial morbidity, suggesting that an interval of >18 months between mastectomy and reconstruction is advisable.

Is Residual Nodal Disease at Axillary Dissection Associated with Tumor Subtype in Patients with Low Volume Sentinel Node Metastasis After Neoadjuvant Chemotherapy?

BACKGROUND: In patients with a positive sentinel lymph node (SLN) after neoadjuvant chemotherapy (NAC), the likelihood of residual nodal disease at axillary dissection (ALND) is high. Whether non-SLN metastasis frequency varies based on tumor subtype and SLN metastasis size is uncertain. We examined the association between tumor subtype and frequency of non-SLN metastases in patients with SLN micro- vs macrometastases after NAC. METHODS: Patients with invasive breast cancer and a positive SLN biopsy after NAC between July 2008 and July 2019 were identified. Associations between tumor subtype, SLN disease volume, and frequency of non-SLN metastases were examined. RESULTS: Among 273 patients with ≥ 1 positive SLN and a completion ALND, mean age was 51 years, 87% of tumors were ductal, 80% were clinically node-positive at presentation, and 85% were cT2-3. The frequency of non-SLN metastases was non-significantly higher in HR+/HER2- (61%) vs. HER2+ (52%) and triple negative tumors (45%) (p = 0.09). Frequency of SLN micrometastasis was 9% for triple negative tumors compared with 17% for HR+/HER2- and 34% for HER2+ tumors (p = 0.015). Size of SLN metastasis (micro- vs. macrometastases) was not associated with non-SLN metastasis frequency or number within any subtype. CONCLUSIONS: In patients with a positive SLN after NAC, the likelihood of non-SLN metastasis at ALND was high across all tumor subtypes and did not vary significantly for SLN micro- versus macrometastases. ALND is recommended for SLN micro- and macrometastases after NAC, irrespective of tumor subtype.

Management of ipsilateral breast tumor recurrence following breast conservation surgery: a comparative study of re-conservation vs mastectomy.

BACKGROUND: Breast conservation therapy (BCT) is well established for the management of primary operable breast cancer, with oncologic outcomes comparable to those of mastectomy. It remains unclear whether re-conservation therapy (RCT) is suitable for those patients who develop ipsilateral breast tumor recurrence (IBTR), for whom mastectomy is generally recommended. METHODS: We identified women who underwent BCT for invasive or ductal carcinoma in situ and developed IBTR as a first event, comparing the pattern of subsequent events and survival for those treated by RCT versus mastectomy. RESULTS: Of 16,968 patents who had BCT, 322 (1.9%) developed an isolated IBTR as a first event between 1999 and 2019. 130 (40%) had RCT and 192 (60%) mastectomy. Compared to mastectomy, the RCT patients were older (66 vs 53, < 0.001), had a longer disease-free interval (DFI: 5.8 vs 2.7 years (p < 0.001)), were less likely to have received RT (p < 0.001), endocrine therapy (ET) (p < 0.005) or combined RT/ET (< 0.001) as initial treatment, but the characteristics of their initial primary cancers and of their IBTR were comparable. At a median follow-up of 10.7 years following initial BCT and 6.5 years following IBTR, there were no differences in BCSS or OS between RCT and mastectomy. CONCLUSION: For BCT patients who developed IBTR as a first event, we observed comparable BCSS and OS from time of initial treatment and from time of IBTR, whether treated by RCT or mastectomy. These results support wider consideration of RCT in the management of IBTR, especially in the setting of older age and longer DFI.

Does Failure to Achieve Pathologic Complete Response with Neoadjuvant Chemotherapy Identify Node-Negative Patients Who Would Benefit from Postmastectomy Radiation or Regional Nodal Irradiation?

BACKGROUND: Postmastectomy radiation (PMRT) and regional nodal irradiation (RNI) improve outcomes for patients at high risk of locoregional recurrence (LRR). Node-negative patients with the triple-negative (TN) subtype and those who do not have a pCR with neoadjuvant chemotherapy (NAC) are at increased risk for LRR, but whether the absolute risk for LRR is high enough to justify PMRT/RNI is uncertain. METHODS: Patients with cT1-T3N0 and pN0 disease treated with NAC who had residual disease in the breast were identified from a prospective database. Patients were eligible for the study if they had mastectomy or breast-conserving therapy with negative margins and whole-breast radiation. Those receiving PMRT or RNI were excluded. Actuarial rates were estimated using the cumulative incidence function. RESULTS: The 227 patients in this study had a mean age was 51.4 ± 12.6 years, and 82 (36.1%) were TN. During a median follow-up period of 35 months, nine LRR events occurred. The overall crude and actuarial 3-year LRR rates were 4.4% and 5.9%, respectively. The crude LRR rate for the TN patients was 7.4%, and the 3-year actuarial rate was 10.1%. The hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) patients had a crude LRR rate of 2.8% and a 3-year actuarial rate of 3.2%. The HER2+ patients had a crude LRR rate of 2.7% and a 3-year actuarial rate of 3.3%. CONCLUSIONS: Locoregional recurrence is uncommon for patients with node-negative HR+/HER2- and HER2+ tumors who have residual disease in the breast; however, TN patients have LRR rates that approach 10% at 3 years, suggesting a possible role for PMRT/RNI for node-negative TN patients. Additional follow-up with more patients is needed for definitive conclusions.

How Often Does Modern Neoadjuvant Chemotherapy Downstage Patients to Breast-Conserving Surgery?

BACKGROUND: Neoadjuvant chemotherapy (NAC) has been proven to increase breast-conserving surgery (BCS) rates, but data are limited on conversion rates from BCS-ineligible (BCSi) to BCS-eligible (BCSe), specifically, in patients with large tumors. METHODS: Consecutive patients with stage I-III breast cancer treated with NAC from November 2013 to March 2019 were identified. BCS eligibility before and after NAC was prospectively determined. Patients deemed BCSi before NAC due to large tumor size were studied. Statistical analyses were conducted using Student's t-test, Wilcoxon rank sum test, Chi-square test, Fisher's test, and logistic regression. RESULTS: In this study, 600 of 1353 cancers were BCSi with large tumors; 69% were non-BCS candidates, 31% were borderline-BCS (bBCS) candidates. Of non-BCS candidates, 69% became BCSe after NAC; 66% chose BCS, and 90% were successful. Among bBCS candidates, 87% were BCSe after NAC, 73% chose BCS, and 96% were successful. On univariate analysis, bBCS candidacy, lower cT stage, cN0 status, absence of calcifications, human epidermal growth factor receptor 2 positive (HER2+)/triple negative (TN) receptor status, poor differentiation, ductal histology, and breast pCR were associated with conversion to BCS eligibility. On multivariable analysis, receptor status (hormone receptor positive [HR+]/HER2- ref; odds ratio [OR] HER2+ 1.63, P = 0.047; HR-/HER2- OR, 2.26, P = 0.003) and breast pCR (OR 2.62, P < 0.001) predicted successful downstaging, while larger clinical tumor size (OR 0.86, P = 0.003), non-BCS candidacy (OR 0.46, P = 0.003), cN+ status (OR 0.54, P = 0.008), and calcifications (OR 0.56, P = 0.007) predicted lower downstaging rates. CONCLUSION: In patients with large tumors precluding BCS, conversion to BCS eligibility was high with NAC, particularly in bBCS candidates. HER2+/TN receptor status predicted successful downstaging, while lower downstaging rates were observed with larger tumors, cN+ status, and calcifications. These factors should be considered when selecting patients for NAC.