The Impact of Different Patterns of Residual Disease on Long-Term Oncological Outcomes in Breast Cancer Patients Treated with Neo-Adjuvant Chemotherapy

BACKGROUNDS

The majority of breast cancer (BC) patients treated with neo-adjuvant chemotherapy (NAC) achieves a pathologic partial response with different patterns of residual disease. No clear correlation between these patterns and oncological results was described. Our aims were to define the predictive factors for different patterns of residual disease and compare the outcomes between the scattered versus the circumscribed pattern.

METHODS

We reviewed 219 postoperative surgical specimens. Patients were divided into two groups: scattered versus circumscribed. Disease-free survival (DFS), distant DFS (DDFS), and overall survival (OS) were analyzed.

RESULTS

The scattered and circumscribed patterns were assessed in 111 (50.7%) and 108 (49.3%) patients. Two independent predictive factors for the circumscribed pattern were identified: discontinuation of NAC cycles (p = 0.011), and tumor size post-NAC >18 mm (p = 0.022). No difference was observed in terms of DFS and DDFS. Patients with the scattered pattern exhibited a statistically significant better OS. Discontinuation of NAC cycles, tumor size >18 mm, triple-negative BC, and ypN+ were associated with increased recurrence and poorer survival.

CONCLUSIONS

Discontinuation of NAC cycles and tumor size are independent factors associated with patterns of residual disease. The scattered pattern presents better survival. Understanding the relationship between NAC, the residual pattern, and differences in survival outcomes offers the potential to optimize the therapeutic approaches.

Comparison of Long-Term Oncological Results in Young Women with Breast Cancer between BRCA-Mutation Carriers Versus Non-Carriers: How Tumor and Genetic Risk Factors Influence the Clinical Prognosis

BACKGROUND

Breast cancer (BC) is very uncommon in young women (YW) and it is unclear whether a BRCA mutation has prognostic implications. Our aim was to evaluate the characteristics of YW with BC by comparing the long-term oncological results between BRCA-mutation carriers and non-carriers.

METHODS

We retrospectively reviewed all the consecutive YW (aged 18-40 years) diagnosed with BC. Endpoints were disease-free survival (DFS), distant disease-free survival (DDFS), and overall survival (OS).

RESULTS

63 YW with a BRCA mutation were compared with 339 YW without BRCA mutation. BRCA-mutation carriers were younger (60.3% versus 34.8% if age ≤ 35 years, p = 0.001) and presented with more aggressive tumors (66.7% versus 40.7% if G3, p = 0.001; 57.2% versus 12.4% if biological subtype triple-negative, p = 0.001; 73.0% versus 39.2% if Ki67 ≥ 25%, p = 0.001). Non-carriers presented significantly better DFS, DDFS, and OS compared with BRCA-mutation carriers. Neoadjuvant chemotherapy was found to be an independent protective factor for OS in BRCA-mutation carriers.

CONCLUSIONS

BC is more likely to present at a younger age (≤ 35 years) and with more aggressive characteristics (G3, triple-negative, Ki67 ≥ 25%) in YW with BRCA mutation compared with their non-mutated counterparts. Young BRCA-mutation carriers showed a poorer prognosis in terms of recurrence and survival compared with non-carriers. The implementation of neoadjuvant chemotherapy may improve survival in YW with BC and BRCA mutation.

Sentinel lymph node biopsy versus axillary lymph node dissection in breast cancer patients undergoing mastectomy with one to two metastatic sentinel lymph nodes: sub-analysis of the SINODAR-ONE multicentre randomized clinical trial and reopening of enrolment

BACKGROUND

The initial results of the SINODAR-ONE randomized clinical trial reported that patients with T1-2 breast cancer and one to two macrometastatic sentinel lymph nodes treated with breast-conserving surgery, sentinel lymph node biopsy only, and adjuvant therapy did not present worse 3-year survival, regional recurrence, or distant recurrence rates compared with those treated with axillary lymph node dissection. To extend the recommendation of axillary lymph node dissection omission even in patients treated with mastectomy, a sub-analysis of the SINODAR-ONE trial is presented here.

METHODS

Patients with T1-2 breast cancer and no more than two metastatic sentinel lymph nodes undergoing mastectomy were analysed. After sentinel lymph node biopsy, patients were randomly assigned to receive either axillary lymph node dissection followed by adjuvant treatment (standard arm) or adjuvant treatment alone (experimental arm). The primary endpoint was overall survival. The secondary endpoint was recurrence-free survival.

RESULTS

A total of 218 patients were treated with mastectomy; 111 were randomly assigned to the axillary lymph node dissection group and 107 to the sentinel lymph node biopsy-only group. At a median follow-up of 33.0 months, there were three deaths (two deaths in the axillary lymph node dissection group and one death in the sentinel lymph node biopsy-only group). There were five recurrences in each treatment arm. No axillary lymph node recurrence was observed. The 5-year overall survival rates were 97.8 and 98.7 per cent in the axillary lymph node dissection treatment arm and the sentinel lymph node biopsy-only treatment arm, respectively (P = 0.597). The 5-year recurrence-free survival rates were 95.7 and 94.1 per cent in the axillary lymph node dissection treatment arm and the sentinel lymph node biopsy treatment arm, respectively (P = 0.821).

CONCLUSION

In patients with T1-2 breast cancer and one to two macrometastatic sentinel lymph nodes treated with mastectomy, the overall survival and recurrence-free survival rates of patients treated with sentinel lymph node biopsy only were not inferior to those treated with axillary lymph node dissection. To strengthen the conclusion of the trial, the enrolment of patients treated with mastectomy was reopened as a single-arm experimental study.

REGISTRATION NUMBER

NCT05160324 (http://www.clinicaltrials.gov).

Pathologic response and residual tumor cellularity after neo-adjuvant chemotherapy predict prognosis in breast cancer patients

INTRODUCTION

Residual tumor cellularity (RTC) and pathologic complete response (pCR) after neo-adjuvant chemotherapy (NAC) are prognostic factors associated with improved outcomes in breast cancer (BC). However, the majority of patients achieve partial pathologic response (pPR) and no clear correlation between RTC patterns and outcomes was described. Our aims were to define predictive factors for pCR and compare different outcomes of patients with pCR or pPR and with different RTC patterns.

MATERIALS AND METHODS

Baseline and post-NAC demographics, clinicopathological characteristics, post-operative data, survival and recurrence status were recorded from our institutional database. A multivariable analysis was performed using a logistic regression model to identify independent predictors of pCR. Disease-free survival (DFS), distant disease-free survival (DDFS), and overall survival (OS) analyses were performed using the Kaplan-Meier method.

RESULTS

Overall, of the 495 patients analyzed, 148 (29.9%) achieved pCR, 347 (70.1%) had pPR, and the median RTC was 40%. Multivariable analysis identified 3 independent factors predictive of pCR: tumor stage before NAC (cT1-2 84.5% versus cT3-4 15.5%), BC sub-type (HER2-positive 54.7% versus triple-negative 29.8% versus luminal-like 15.5%), and vascular invasion (absence 98.0% versus presence 2.0%). We found statistically significant longer DFS, DDFS, and OS in patients with pCR and with RTC <40%; no difference was observed in terms of OS between RTC <40% and RTC ≥40% groups.

CONCLUSIONS

Tumor stage before NAC, BC sub-type, and vascular invasion are significant and independent factors associated with pCR. Patients with pCR and with RTC <40% have longer DFS, DDFS, and OS compared with patients with pPR.

Sentinel Lymph Node Biopsy in Breast Cancer Patients Undergoing Neo-Adjuvant Chemotherapy: Clinical Experience with Node-Negative and Node-Positive Disease Prior to Systemic Therapy

Background: Sentinel lymph node biopsy (SLNB) has emerged as the standard procedure to replace axillary lymph node dissection (ALND) in breast cancer (BC) patients undergoing neo-adjuvant chemotherapy (NAC). SLNB is accepted in clinically node-negative (cN0) patients; however, its role in clinically node-positive (cN+) patients is debatable. Methods: We performed a retrospective analysis of BC patients undergoing NAC and SLNB. Our aim was to evaluate the clinical significance of SLNB in the setting of NAC. This was accomplished by comparing the characteristics and oncological outcomes between cN0 and cN+ patients prior to NAC and type of axillary surgery. Results: A total of 291 patients were included in the analysis: 131 were cN0 and 160 were cN+ who became ycN0 after NAC. At a median follow-up of 43 months, axillary recurrence occurred in three cN0 (2.3%) and two cN+ (1.3%) patients. However, there were no statistically significant differences in oncological outcomes (disease-free survival, distant disease-free survival, overall survival, and breast-cancer-specific survival) between cN0 and cN+ patients nor between patients treated with SLNB only or ALND. Conclusions: SLNB in the setting of NAC is an acceptable procedure with a general good prognosis and low axillary failure rates for both cN0 and cN+ patients.

Abstract P1-09-09: Salvage mastectomy is not always necessary for aggressive subtypes of ipsilateral breast cancer recurrence: A single-institution retrospective study

Introduction: Patients with triple-negative (TN) or HER2-enriched ipsilateral breast cancer recurrence (IBCR) seem to be excluded from a second breast-conserving surgery (BCS) under the assumption that salvage mastectomy would provide better oncological outcomes. Objectives: The objective of this study was to describe the clinical features of these patients, to compare the two surgical alternatives (salvage mastectomy versus second BCS) in terms of oncological results, and to identify independent factors influencing prognosis and surgical treatment. Methods: We retrospectively reviewed all the consecutive patients with histologically confirmed TN or HER2-enriched IBCR. Disease-free survival (DFS), distant disease-free survival (DDFS), overall survival (OS), and breast cancer-specific survival (BCSS) were analyzed and compared between the two groups. Results: Eighty-five patients were affected by TN or HER2-enriched IBCR, with a median age of 60 years (range, 32-87 years). The majority of patients (72.9%) were treated with salvage mastectomy. There was no significant difference in terms of DFS between patients receiving a second BCS or mastectomy (p=0.596). However, patients undergoing a second BCS had significantly better DDFS, OS, and BCSS compared to mastectomy (p=0.009; p=0.002; p=0.001, respectively). Tumor dimension &lt; 16 mm (78.3% versus 38.7%, hazard ratio (HR)=3.602, 95% confidence interval (95% CI)=1.534-8.459, p=0.003) was found to significantly increase the probability of receiving a second BCS and positively affects recurrence and survival outcomes (DFS: HR=8.065, 95% CI=2.320-28.034, p=0.001; DDFS: HR=17.011, 95% CI=3.853-75.099, p=0.001; OS: HR: 13.881, 95% CI=2.730-70.579, p=0.002; BCSS: HR=36.773, 95% CI=4.579-295.322, p=0.001). Second BCS represents an independent protective factor for OS and BCSS (OS: HR=0.246, 95% CI=0.027-0.697, p=0.002; BCSS: HR=0.313, 95% CI=0.092-0.511, p=0.002). Conclusion: Salvage mastectomy is not always necessary and it does not seem to increase survival compared to a second BCS. This reinforces the concept that the prognosis of TN and HER2-enriched BC recurrence is mainly driven by the biology of the disease, rather than by the extent of surgery. In patients with small (&lt; 16 mm) aggressive subtypes of IBCR, a second conservative approach can still be evaluated and offered, presenting acceptable loco-regional control and survival.

Citation Format: Damiano Gentile, Andrea Sagona, Erika Barbieri, Simone Di Maria Grimaldi, Ruggero Spoto, Davide Franceschini, Stefano Vaccari, Valeriano Vinci, Ersilia Biondi, Lorenzo Scardina, Corrado Tinterri. Salvage mastectomy is not always necessary for aggressive subtypes of ipsilateral breast cancer recurrence: A single-institution retrospective study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-09-09.

Abstract P6-01-32: Evaluation of pathologic response and residual tumor cellularity following neo-adjuvant chemotherapy predict prognosis in breast cancer patients

Introduction: Treatment of early-stage beast cancer (BC) has changed since recent evidence showed that neoadjuvant chemotherapy (NAC) can reduce residual tumor cellularity (RTC) and improve patient outcomes. Achieving a pathologic complete response (pCR) has been associated with significantly improved disease-free survival (DFS), distant disease-free survival (DDFS), and overall survival (OS). However, among patients treated with NAC, few experience pCR, while approximately 60-80% of them achieve a pathologic partial response (pPR). In previous studies, BC patients with different grades of pPR have been usually grouped and analyzed together, with inconsistent results and unclear prognostic significance. Objectives: The primary aims of this study were to describe the clinical and treatment characteristics of BC patients treated with NAC, to identify independent predictive factors of pCR, and to compare the oncologic outcomes between patients achieving pCR or pPR. The secondary aim of this study was to measure the RTC of BC patients with pPR and to compare the outcomes of patients with different RTC in order to improve prognostic information. Methods: All the consecutive BC patients undergoing NAC at the Breast Unit of IRCCS Humanitas Research Hospital (Milan, Italy) between October 2006 and April 2020 and their corresponding post-operative pathology slides were reviewed. The following exclusion criteria were used: excisional biopsy or debulking surgery as first BC operation, patients with a previous BC diagnosis or other prior or synchronous malignancies, male patients, unknown NAC regimen, disease progression during NAC, and follow-up ≤12 months. Results: A total of 495 BC patients received NAC. Overall, 148 (29.9%) patients achieved pCR, while 347 (70.1%) had pPR, and median RTC was 40%. At multivariable analysis, 3 independent factors predicting pCR were identified. Tumor stage pre-NAC (cT1-2 84.5% versus cT3-4 15.5%, odds ratio (OR)=0.119, 95% confidence interval (95%CI)=0.048-0.189, p=0.001), BC sub-type (HER2-enriched 54.7% versus triple-negative 29.8% versus luminal-like 15.5%, OR=2.178, 95%CI=2.055-2.301, p=0.001), and vascular invasion (absence 98.0% versus presence 2.0%, OR=0.022, 95%CI=0.004-0.090, p=0.001). Patients with BC undergoing NAC and achieving pCR presented statistically significant longer DFS, DDFS, and OS (p = &lt; 0.001). Patients with RTC &lt; 40% presented statistically significant better DFS and DDFS (p = 0.033, p = 0.015, respectively). However, no statistically significant difference in terms of OS was observed between RTC &lt; 40% and RTC ≥40% groups (p = 0.148). Conclusions: Tumor stage pre-NAC, BC sub-type, and vascular invasion are significantly and independently associated with pCR. Patients with pCR present a better prognosis compared to patients with pPR in terms of DFS, DDFS, and OS. Measurement of RTC in BC patients with pPR improves the prognostic information that can be obtained from the assessment of the pathologic response. Different patterns of residual disease play an important role in predicting the risk of subsequent loco-regional and distant recurrence, and patients with RTC &lt; 40% present significantly better DFS and DDFS.

Citation Format: Damiano Gentile, Andrea Sagona, Camilla De Carlo, Bethania Fernandes, Simone Di Maria Grimaldi, Erika Barbieri, Wolfgang Gatzemeier, Lorenzo Scardina, Ersilia Biondi, Flavia Jacobs, Giulia Vatteroni, Corrado Tinterri. Evaluation of pathologic response and residual tumor cellularity following neo-adjuvant chemotherapy predict prognosis in breast cancer patients [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-32.

Preservation of Axillary Lymph Nodes Compared with Complete Dissection in T1-2 Breast Cancer Patients Presenting One or Two Metastatic Sentinel Lymph Nodes: The SINODAR-ONE Multicenter Randomized Clinical Trial

BACKGROUND

The SINODAR-ONE trial is a prospective noninferiority multicenter randomized study aimed at assessing the role of axillary lymph node dissection (ALND) in patients undergoing either breast-conserving surgery or mastectomy for T1-2 breast cancer (BC) and presenting one or two macrometastatic sentinel lymph nodes (SLNs). The endpoints were to evaluate whether SLN biopsy (SLNB) only was associated with worsening of the prognosis compared with ALND in terms of overall survival (OS) and relapse.

METHODS

Patients were randomly assigned (1:1 ratio) to either removal of ≥ 10 axillary level I/II non-SLNs followed by adjuvant therapy (standard arm) or no further axillary treatment (experimental arm).

RESULTS

The trial started in April 2015 and ceased in April 2020, involving 889 patients. Median follow-up was 34.0 months. There were eight deaths (ALND, 4; SNLB only, 4), with 5-year cumulative mortality of 5.8% and 2.1% in the standard and experimental arm, respectively (p = 0.984). There were 26 recurrences (ALND 11; SNLB only, 15), with 5-year cumulative incidence of recurrence of 6.9% and 3.3% in the standard and experimental arm, respectively (p = 0.444). Only one axillary lymph node recurrence was observed in each arm. The 5-year OS rates were 98.9% and 98.8%, in the ALND and SNLB-only arm, respectively (p = 0.936).

CONCLUSIONS

The 3-year survival and relapse rates of T1-2 BC patients with one or two macrometastatic SLNs treated with SLNB only, and adjuvant therapy, were not inferior to those of patients treated with ALND. These results do not support the use of routine ALND.

Abstract P3-18-16: Breast conserving surgery in BRCA-mutation carriers. A single Institution experience

BackgroundBRCA-mutation carriers have a lifetime risk of breast cancer (BC) that ranges from 36 to 70%. For patients (pts) without mutation, breast conserving surgery (BCS) (followed by radiation therapy) is the treatment of choice since it offers similar survival to that of unilateral mastectomy. However, the optimal local management in BRCA-mutation carriers remains a matter of debate and the role of bilateral salpingo-oophorectomy (BSO) in reducing BC risk might be influenced by age and medical BC treatments (such as GnRH analogues). Patients and methodsWe retrieved clinical pathologic characteristics of 124 BRCA-mutated BC pts, consecutively tested at our Institution from 2008 to 2018. Primary end-point was recurrence-free survival (RFS) evaluation in terms of disease-free survival (DFS), distant DFS (DDFS) and overall survival (OS). Secondary end-point was identification of independent predictive factors for BCS. Clinical pathologic characteristics were evaluated and compared using univariate and multivariate analysis. Kaplan-Mayer curves were used to describe DFS, DDFS and OS. ResultsMedian age at BC surgery was 41 years (range 24-74), most of the pts (79%) were pre-menopausal and presented with ductal invasive carcinoma (91.9%). As per biological subtype, 63 (50.8%) pts had luminal-like BC, 52 (41.9%) triple negative (TN) BC and 9 (7.3%) HER2 enriched-like BC. More than half pts (62.9%) presented with G3 tumors and median Ki-67 was 40% (range 5-95). 17 (13.7%) and 80 (64.5%) pts underwent neo-adjuvant and adjuvant chemotherapy, respectively; 64 (51.6%) pts received adjuvant endocrine therapy, 39 (31.5%) with the addition of GnRH analogue. When comparing BCS to mastectomy, regardless of BSO, we could not observe any statistically significant difference in all the RFS end-points. 10-year DFS rate was 56.4% and 79.5%, respectively (p=0.187); 10-year DDFS rate was 83.7% and 82.3%, respectively (p=0.689); 10-year OS rate was 87.7% and 85.1%, respectively (p=0.947). At a multivariate analysis, age ≤41 years (p=0.008; OR 0.309; 95% CI 0.190-0.513) and primary tumor dimension ≤21 mm (p=0.008; OR 0.320; 95% CI 0.114-0.426), were the only predictors of breast surgery type (BCS compared to any other surgical treatment). ConclusionsOur data suggest that young pre-menopausal BRCA-mutated pts with small tumors may not need up-front mastectomy and BSO might be postponed, when ovarian cancer risk epidemiologically rises and potential reproductive desire is fulfilled.

Citation Format: Agnese Losurdo, Damiano Gentile, Monica Zuradelli, Andrea Sagona, Erika Barbieri, Monica Barile, Paolo Bianchi, Rosalba Torrisi, Wolfgang Gatzemeier, Marta Scorsetti, Corrado Tinterri, Armando Santoro. Breast conserving surgery in BRCA-mutation carriers. A single Institution experience [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-18-16.

Abstract GS4-05: Preservation of axillary lymph nodes compared to complete dissection in T1-T2 breast cancer patients presenting 1-2 metastatic sentinel lymph nodes. A multicenter randomized clinical trial. Sinodar One

Introduction: Sentinel lymph node (SLN) staging is currently used to avoid complete axillary lymph node dissection (ALND) in breast cancer (BC) patients. The SLN is the only site of axillary metastasis (MTS) in ≥60% of cases. Recently, a randomized controlled trial (Z0011) comparing SLN biopsy (SLNB) alone with SLNB followed by ALND in patients with 1-2 SLNs+ demonstrated no significant statistical difference in relapse and overall survival (OS) rates among the two different groups. However, this study had some limitations: small tumor size (≤2cm in 70% of cases), frequent presence of only microMTS in SLN (40%), prevalent use of “whole breast” adjuvant radiotherapy (&gt;90%). Given these considerations, the SINODAR-ONE study started in April 2015. Objectives: The aims are to assess whether ALND omission in BC patients with 1-2 SLNs+ is associated with worse survival and/or increased rate of regional/distant relapse. Thus evaluating whether SLNB is or is not inferior to ALND. Primary endpoint is OS. Secondary endpoints are disease-free survival (DFS) referring to distant MTS and loco-regional recurrence. Methods: Patients received either mastectomy or conservative surgery plus radiotherapy. They all underwent SLNB and were randomly divided into two arms of treatment: standard (SLNB plus ALND) or experimental treatment (only SLNB). According to multidisciplinary evaluation, patients could undergo additional adjuvant radiotherapy, chemo- and/or hormonal therapy, or no further therapy. Eligibility criteria: age 40-75 years; primary invasive T1-T2 tumor; axillary nodes cN0; no more than 2 macro-metastatic SLNs; no distant MTS; no neo-adjuvant therapy; no previous invasive BC. Exclusion criteria: in situ, inflammatory, contralateral BC; micro-metastatic SLNs; pregnancy or breast feeding; comorbidity impeding adjuvant therapy. All analyses were performed both on all patients according to the Intention-To-Treat principle and excluding those patients who did not receive the axillary treatment randomly assigned. Statistical analysis: OS and DFS were calculated using the Kaplan-Meier Product Limit Estimator and differences between arms were assessed with the log-rank test. Results: The enrollment of patients ended in April 2020 with a total of 889 cases (443: standard arm; 446: experimental arm). In April 2021, we conducted a preliminary analysis on 889 patients. We found the two groups homogeneous for epidemiologic characteristics (age and menopausal status), tumor characteristics (tumor size, pTNM, immunohistochemistry, histology, grading, vascular and lymphatic invasion), and adjuvant therapies. The majority of patients (77.2%) received breast conserving surgery, while 22.8% of patients underwent mastectomy. A median of 2 SLNs were removed in both arms. Overall, only 3 micro-metastatic SNLs were found (1 in the standard arm and 2 in the experimental arm). Conclusion: In sum, OS rate is 99.1% and 99.3% in the standard and experimental arm, respectively; DFS rate is 96.8% and 95.9% in the standard and experimental arm, respectively. After a median follow-up of 36 months, there has been only one axillary recurrence in the experimental arm. Additionally, we found seven distant relapses in both arms; four and three deaths in the standard and experimental arm, respectively.

Citation Format: Damiano Gentile, Wolfgang Gatzemeier, Erika Barbieri, Andrea Sagona, Alberto Bottini, Valentina Errico, Alberto Testori, Marta Scorsetti, Giuseppe Canavese, Corrado Tinterri. Preservation of axillary lymph nodes compared to complete dissection in T1-T2 breast cancer patients presenting 1-2 metastatic sentinel lymph nodes. A multicenter randomized clinical trial. Sinodar One [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS4-05.

Neo-Adjuvant Chemotherapy in Luminal, Node Positive Breast Cancer: Characteristics, Treatment and Oncological Outcomes: A Single Center's Experience

Objective

Neo-adjuvant chemotherapy (NAC) is the treatment of choice for patients with locally advanced breast cancer (BC). In luminal-like BC, the decision to administer NAC remains controversial. The purpose of this study was to describe the clinical characteristics, treatment, and oncological outcomes of luminal-like, node positive, BC patients treated with NAC, and to identify independent predictive factors for treatment.

Materials and Methods

All consecutive patients with luminal-like, node positive BC who underwent NAC were retrospectively reviewed. Pathologic complete response (pCR) was defined as no invasive or in situ residual tumor in both breast and axillary nodes (ypT0N0).

Results

A total of 205 luminal-like, node positive BC patients underwent NAC. Overall, 34 (16.6%) patients showed pCR, 86 (42.0%) patients underwent breast-conserving surgery (BCS), 119 (58.0%) patients underwent mastectomy, 130 (63.4%) patients underwent axillary lymph node dissection (ALND) without prior sentinel lymph node biopsy (SLNB), and 75 (36.6%) patients underwent breast surgery plus SLNB. Pathologic CR to NAC (29.1% vs 7.6% if no pCR, odds ratio = 2.866, 95% confidence interval = 1.296-6.341, p = 0.009) was found to significantly increase the probability to receive BCS. There was no significant difference in terms of disease-free and overall survival between patients with luminal-like, node positive BC receiving BCS or mastectomy (p = 0.596, p = 0.134, respectively), and ALND or SLNB only (p = 0.661, p = 0.856, respectively).

Conclusion

Luminal-like, node positive BC presents low pCR rates after NAC. Pre-operative chemotherapy increases the rate of BCS. Pathologic CR has emerged as an independent predictive factor for BCS. In patients with axillary pCR, SLNB is an acceptable procedure not associated with worse oncological outcomes.

Long term results of a phase II trial of hypofractionated adjuvant radiotherapy for early-stage breast cancer with volumetric modulated arc therapy and simultaneous integrated boost

PURPOSE

to report toxicity and cosmetic outcome with a median follow-up of 6 years of a phase II trial of hypofractionated radiotherapy with volumetric modulated arc therapy (VMAT) and simultaneous integrated boost (SIB) for early-stage breast cancer after conservative surgery.

MATERIALS AND METHODS

From August 2010 to September 2014, patients requiring adjuvant radiotherapy for early-stage breast cancer were treated according to a phase I-II protocol with SIB to 40.5 and 48 Gy to the breast and the boost region, respectively, with VMAT technique. The primary endpoint evaluated the treatment feasibility regarding adherence to required dose constraints for target, heart and lungs. Acute and late toxicity, local and distant control were secondary endpoints.

RESULTS

450 patients were included in the trial and analysed after a median follow-up of 6 years. Acute toxicity was already presented in a previous paper. Regarding late toxicity, 93% of patients had no skin alteration at five years, while 5.3% and 1.3% did record G1 and G2 residual toxicity, respectively. Cosmetic outcome was scored good or excellent in almost all cases (97.2%), fair only in 2.3% of patients. Residual tenderness in the irradiated breast was reported by 10% of patients. Cosmesis and breast pain improved during follow-up. Two cases of G2 pneumonitis and two cases of ischemic cardiopathy were registered during follow-up. Five cases presented local recurrence in the homolateral breast, four patients had a new primary cancer in the contralateral breast, while distant metastasis developed in 7 patients.

CONCLUSION

After more than six years, hypofractionated VMAT with SIB for adjuvant radiotherapy in early-stage breast cancer patients remains a safe and effective approach. Mature data on skin toxicity and cosmetic outcome are encouraging. However, longer follow-up is required to evaluate local control, cardiac toxicity and secondary carcinogenesis.

Breast conserving surgery versus salvage mastectomy for ipsilateral breast cancer recurrence: a propensity score matching analysis

Salvage mastectomy is regarded as the treatment of first choice for ipsilateral breast cancer recurrence (IBCR), even if a second breast conserving surgery (BCS) is feasible. The purpose of this study was to compare the long-term oncological outcomes of IBCR patients who had undergone either mastectomy or second BCS, performing a propensity score matching (PSM) analysis to reduce the selection bias. All the consecutive patients with IBCR were retrospectively reviewed and divided into two different groups of treatment: repeat BCS versus salvage mastectomy. The propensity score predicting the probability of surgical treatment was determined for each patient and a 1:1 matching was performed. Disease-free survival (DFS), distant disease-free survival (DDFS), overall survival (OS), and breast cancer-specific survival (BCSS) were analyzed and compared between the two groups. A total of 309 patients underwent surgical treatment for IBCR. After PSM, 108 patients treated with repeat BCS and 108 patients treated with salvage mastectomy were included in the analysis. There was no significant difference in terms of DFS between patients with IBCR receiving repeat BCS or salvage mastectomy (p = 0.167). However, patients with IBCR undergoing second BCS had significantly better DDFS, OS, and BCSS compared to salvage mastectomy (p < 0.001). Salvage mastectomy should not be considered the optimal treatment for IBCR and it does not seem to improve prognosis compared to repeat conserving surgery. Second BCS for IBCR is a safe option with encouraging long-term oncological outcomes and should be proposed to all patients, when technically feasible.

Abstract PD4-01: Preservation of axillary lymph nodes compared to complete dissection in T1-T2 breast cancer patients presenting 1-2 metastatic sentinel lymph nodes : A multicenter randomized clinical trial. Sinodar One

Introduction: Sentinel lymph node (SLN) staging is currently used to avoid complete axillary lymph node dissection (ALND) in breast cancer (BC) patients. The SLN is the only site of axillary metastasis (MTS) in ≤60% of cases. Recently, a randomized controlled trial (Z0011) comparing SLN biopsy (SLNB) alone with SLNB followed by ALND in patients with 1-2 SLNs+ demonstrated no significant statistical difference in relapse and overall survival rates among the two different groups. However, this study had some limitations: small tumor size (≤2cm in 70% of cases), frequent presence of only microMTS in SLN (40%), prevalent use of “whole breast” adjuvant radiotherapy (&gt;90%). Given these considerations, the SINODAR-ONE study started in April 2015.Objectives: The aims are to assess whether ALND omission in BC patients with 1-2 SLNs+ is associated with worse survival and/or increased rate of regional/distant relapse. Thus evaluating whether SLNB is or is not inferior to ALND. Primary endpoint is overall survival (OS). Secondary endpoints are disease-free survival (DFS) referring to distant MTS and loco-regional recurrence. Methods: Patients receive either mastectomy or conservative surgery plus radiotherapy. They all undergo SLNB and are randomly divided into two arms of treatment: standard (SLNB plus ALND) or experimental treatment (only SLNB). According to multidisciplinary evaluation, patients may undergo additional adjuvant radiotherapy, chemo- and/or hormonal therapy , or no further therapy. Eligibility criteria: age 40-75 years; primary invasive T1-T2 tumor; axillary nodes clinically N0; no more than 2 macro-metastatic SLNs; no distant MTS; no neo-adjuvant therapy; no previous invasive BC; signed informed consent. Exclusion criteria: in situ, inflammatory, contralateral BC; micro-metastic SLNs; pregnancy or breast feeding; comorbidity impeding adjuvant therapy. All analyses are performed both on all patients according to the Intention-To-Treat principle and excluding those patients who did not receive the axillary treatment randomly assigned. Statistical analysis: OS and DFS are calculated using the Kaplan-Meier Product Limit Estimator and differences between arms are assessed with the log-rank test. Results: The enrollment of patients ended in April 2020 with a total of 889 cases (443: standard arm; 446: experimental arm). In June 2020, we conducted an ad interim analysis on 889 patients. We found the two groups homogeneous for epidemiologic characteristics (age and menopausal status), tumor characteristics (tumor size, pTNM, immunohistochemistry, histology, grading, vascular and lymphatic invasion), adjuvant therapies and surgery on T. In particular we have performed a 23,1% of mastectomies in the standard arm and 20,1% in the experimental arm. We found a median of 2 sentinel lymph nodes removed in both arms and 1 non-sentinel positive lymph node in the experimental arm, and only 3 micro-metastases (1 in the standard arm and 2 in the experimental arm). Conclusion: In sum, with a median follow-up of 30 months, there have been no axillary recurrence in both arms. In the standard arm we found 8 total events (2 deaths and 6 distant relapses) and in in the experimental arm 6 events (1 death and 5 distant relapses), with a projected 5-years cumulative incidence of 6,5% in standard arm and 4,85% in the experimental arm.

Citation Format: Corrado Tinterri, Emilia Marrazzo, Chiara Anghelone, Erika Barbieri, Andrea Sagona, Alberto Bottini, Arianna Rubino, Damiano Gentile, Wolfgang Gatzemeier, Valentina Errico, Alberto Testori, Giuseppe Canavese. Preservation of axillary lymph nodes compared to complete dissection in T1-T2 breast cancer patients presenting 1-2 metastatic sentinel lymph nodes : A multicenter randomized clinical trial. Sinodar One. [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD4-01.

Abstract PS1-16: Ipsilateral breast cancer recurrence: Treatment and long-term oncological results at a high volume center

Background A small proportion of patients with primary breast cancer who receive breast conserving surgery (BCS) will develop an ipsilateral breast cancer recurrence (IBCR). In these patients, mastectomy is still considered the treatment of first choice, even if a second conservative surgical approach is technically feasible. The aims of our study are to analyze the characteristics of patients with IBCR after BCS, evaluate and compare the different treatment modalities (repeat BCS vs. mastectomy) in terms of patients and tumor characteristics, disease-free interval (DFI), disease-free survival (DFS), and overall survival (OS).MethodsOur prospectively maintained institutional database was queried, and 309 patients with IBCR after BCS who underwent either repeat BCS or mastectomy, between January 2008 and December 2018, were identified. Ipsilateral breast cancer recurrence was defined as a local tumor reappearance in the same breast or in the surgical scar. Exclusion criteria were: age &lt;18 years, primary cancer treated with mastectomy, residual disease, controlateral recurrence, recurrent benign disease, only distant or axillary recurrence, IBCR not treated surgically, follow-up &lt;24 months, and DFI &lt;6 months.ResultsThe mean age of patients at primary breast cancer was 55.3 years. The majority of primary tumors were ductal (87.4%), luminal A-B (81.2%) breast cancers. After BCS, 222 (71.8%) patients underwent radiotherapy. Out of 309 patients with IBCR after BCS, 143 underwent repeat BCS and 166 underwent mastectomy. At multivariable analysis, young age, &lt;65 years (59.6% vs. 37.1% if age ≥65 years, odds ratio (OR)=2.374, 95% confidence interval (95%CI)=0.02-0.24, p= 0.018) and short DFI &lt;24 months (15.7% vs. 10.5% if DFI ≥24 months, OR=2.705, 95%CI=0.02-0.17, p= 0.007) were found to significantly increase the probability to receive mastectomy for IBCR after BCS. After IBCR, DFS rate at 3-, 5-, and 10-years was 79.2%, 68.2%, 36.9%, and 77.2%, 65.9%, 55.3%, in patients receiving repeat BCS or mastectomy, respectively (p = 0.842). Overall-survival rate at 3-, 5-, and 10-years was 95.4%, 91.4%, 68.5%, and 87.3%, 69.3%, 57.9%, in patients receiving repeat BCS or mastectomy, respectively (p = 0.018).ConclusionsThe best candidates for repeat BCS in the treatment of IBCR are patients ≥65 years with a DFI ≥24 months. Young patients (&lt;65 years) with early onset of recurrence (DFI &lt;24 months) have a high probability to receive mastectomy for the treatment of IBCR. Mastectomy does not improve survival in patients with IBCS after BCS. The information about the risk of poor long-term prognosis after mastectomy should be shared with the patient and a repeat BCS could be proposed.

Citation Format: Damiano Gentile, Andrea Sagona, Chiara Annunziata Pasqualina Anghelone, Erika Barbieri, Emilia Marrazzo, Wolfgang Gatzemeier, Giuseppe Canavese, Valentina Errico, Alberto Testori, Corrado Tinterri. Ipsilateral breast cancer recurrence: Treatment and long-term oncological results at a high volume center [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-16.

Ipsilateral Breast Cancer Recurrence: Characteristics, Treatment, and Long-Term Oncologic Results at a High-Volume Center

INTRODUCTION

Salvage mastectomy is considered the treatment of choice for ipsilateral breast cancer recurrence (IBCR), even if a second breast-conserving surgery (BCS) is feasible. The purpose of this study was to describe the characteristics of IBCR patients, to compare the 2 therapeutic options in terms of long-term outcomes, and to identify independent factors that may predict the type of treatment.

PATIENTS AND METHODS

A total of 309 IBCR patients who underwent either repeat BCS or mastectomy were identified. All the analyzed patients with IBCR had true recurrence.

RESULTS

Repeat BCS and salvage mastectomy were performed in 143 and 166 patients, respectively. Age < 65 years (59.6% vs 37.1% if age ≥ 65 years; odds ratio, 2.374; 95% confidence interval, 0.92-5.24; P = .018) and disease-free interval < 24 months (15.7% vs 10.5% if disease-free interval ≥ 24 months; odds ratio, 2.705; 95% confidence interval, 1.42-5.97; P = .007) were found to significantly increase the probability of receipt of mastectomy. Disease-free survival rates at 3, 5, and 10 years were 79.2%, 68.2%, and 36.9%; and 77.2%, 65.9%, and 55.3% in patients receiving repeat BCS or mastectomy, respectively (P = .842). Overall survival rates at 3, 5, and 10 years were 95.4%, 91.4%, and 68.5%; and 87.3%, 69.3%, and 57.9%, respectively, in patients receiving repeat BCS or mastectomy (P = .018).

CONCLUSION

Salvage mastectomy should not be considered the only treatment option for IBCR. A second BCS can still be evaluated and proposed to IBCR patients, with acceptable locoregional control and survival. The risk of poor long-term prognosis after mastectomy should be shared with the patient.

Evolution and time trends of nipple-sparing mastectomy: a single-center experience

Nipple Sparing Mastectomy (NSM) requires the entire breast tissue to be removed, maintaining the nipple-areola complex, and represents nowadays the gold standard of the demolitive breast surgery. Although it represents the evolution of conservative breast surgery, NSM presents some limitations in the selection of women candidates for treatment, and still there are no real guidelines regarding its indications, but simply objective data to address the choice. How the breast surgery approach to demolitive and conservative surgery has changed over time? We evaluated throughout the years (from 2009 up to 2018) the time trend of NSM at our institution and analysed the main differences between patients undergone NSM and other mastectomies and/or breast conserving surgery in terms of cancer size, multicentricity and biological profile. We found 781 NSMs, 1261 other mastectomies and 5621 breast conservative surgeries. Among NSMs, 39.6% were reconstructed with tissue expander and 58.1% with definitive prosthesis. From 2009 to 2018 we found a general increase of NSM rate (from 21.3% of all mastectomies in 2009 to 67.3% in 2018) and a decrease of total mastectomies (from 78.7% of all mastectomies in 2009 to 32.7% in 2018). In line with the literature data, our data confirm that in the recent years NSM represents the gold standard for radical breast surgery. Undisputed in prophylaxis, NSM is continuously acquiring more support in being used as first line treatment for locally advanced disease.

Abstract P5-04-07: Defining T cell dysfunctionality in breast cancer by single cell analysis: Implications for immunotherapy

Background Despite the well-known association between extensive lymphocytic infiltration in breast cancer (BC), good prognosis, and high response rates to neoadjuvant chemotherapy (CT), pathologic evaluation of tumor infiltrating lymphocytes (TILs) is currently not routine and a deep understanding of the properties of TILs, remain largely unfilled. So far, only in triple-negative (TN), PD-L1 positive BCs it has been possible to demonstrate a survival benefit with immunotherapy plus CT, thereby making the definition of possible immunotherapeutic targets across all biological subtypes a fundamental requirement. Material and methods Single-cell RNA-sequencing (scRNAseq) data from 8 BCs were downloaded from Gene Expression Omnibus dataset (GSE114725), obtaining CD45+ single cells only from the tumoral compartment. scRNAseq-guided high-dimensional profiling by 27-parameter FACS was then applied to a large cohort (n=54, including luminal-like, TN and HER2+ BCs) of early BC patients surgically treated at our Institution. We simultaneously profiled the peripheral blood, the normal and tumoral tissue from each patient and acquired using FACS Symphony A5 flow cytometer (BD Biosciences). Flow Cytometry Standard (FCS) 3.0 files were imported into FlowJo software v9, and analyzed by standard gating to remove aggregates and dead cells, and subsequently imported in FlowJo v10, biexponentially transformed, and exported for further analysis in R by a custom-made script, using an ad-hoc pipeline. Data were analyzed using the Phenograph unbiased algorithm coded in the cytofkit package. Data were further analyzed in FlowJo to determine the frequency of positive cells for each marker and the corresponding median fluorescence intensity (MFI). These values were multiplied to derive the integrated MFI; hierarchical metaclustering of all samples, based on the frequency of Phenograph clusters, was performed in R based on the Euclidean distance and Ward-linkage. Pearson correlation analysis was used to investigate the relationship between CD8+ and CD4+ clusters. Results Our scRNA-guided informative 27-colors flow cytometry panel included antibodies to define not only different lymphocyte subpopulations, but also different stages of T lymphocytes: differentiation and memory maturation (CCR7, CD45RA), activation status (HLA-DR), cytotoxicity (GZMK, GZMB), exhaustion (PD-1, TIGIT) and tissue residency (CD69, CD103). Focusing on CD8+ T cells, we observed, as expected, bona fide naïve T cells to be virtually absent at the tumor site and enriched in peripheral blood, while cytotoxic and effector memory cells were enriched in the tumor compartment. Of note, we identified a population of tissue resident memory T cells (Trm) CD69+ CD103+, CD39+, specifically enriched in the tumor, that could be further subdivided into a HLA-DR+ CD127- and a HLA-DR- CD127+ subpopulation. Interestingly, the HLA-DR+ subset exhibited more exhaustion markers (PD-1hi, TIGIT+, NKG2A+) and was significantly positively correlated with CD4+ regulatory T cells. We speculated, and deeply investigated by bulk RNA-seq, that these two subsets of Trm might represent different maturation states and that they could be reinvigorated targeting highly expressed inhibitory molecules using approved (e.g., PD-1) together with newly identified (e.g., NKG2A) immunotherapeutics. Moreover, as no difference was observed in the relative distribution of Phenograph clusters, our data may be applied to revert acquired immune escape mechanisms in all different BC biological subtypes. Conclusions We identified, among Trm CD69+ CD103+, tumor-specific CD39+, PD1+ exhausted population, novel dysfunctional NKG2A+ T cells previously not characterized in BC. This population is of extreme interest to characterize a novel potential immunotherapeutic target.

Citation Format: Agnese Losurdo, Caterina Scirgolea, Emilia Mazza, Valentina Errico, Bethania Fernandes, Luca Di Tommaso, Andrea Sagona, Karolina Pilipow, Rosalba Torrisi, Giovanna Masci, Rita De Sanctis, Elisa Agostinetto, Alberto Testori, Corrado Tinterri, Massimo Roncalli, Armando Santoro, Enrico Lugli. Defining T cell dysfunctionality in breast cancer by single cell analysis: Implications for immunotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-04-07.

Abstract OT3-01-03: Neonod Study: Conservation of axillary lymph nodes in the presence of micrometastases in the sentinel lymph node if cN- After neoadjuvant chemotherapy

Background: In the last 20 years it was observed a clear trend to develop and perform less and less demolitive axillary surgery in breast cancer patients. The development of identification, dissection and intraoperative analysis of sentinel lymph node (SLNB, Sentinel Lymph Node Biopsy) contributed to give all informations on the need to proceed or not to axillary lymph node dissection (ALND), while neoadjuvant chemotherapy (NAC) permitted to enable surgical treatment in initially non-operable cancers or to reduce tumor size in order to perform a less demolitive surgery. In Patients with residual axillary disease after NAC, it is not completely clear if the prognosis worsens according to the entity of residual disease (isolated tumor cells or ITC, micrometastases, macrometastases). In particular, IBCSG 23-01 study demonstrated that, in patients with ypN1mi early breast cancer, axillary lymph node dissection (ALND) could be avoided without worsening the prognosis. Assuming that patients cN+ before, but ypN1mi after NAC are clinically equivalent to patients in IBSCG study, complete ALND would be useless even if in patients subjected to NAC for that subgroup. Still it is to demonstrate if axillary micrometastases after NAC could have a prognostic value similar to micrometastasis in patients subjected to adjuvant treatment. To overcome these limitations, we propose this non-controlled clinical study to verify the effect of avoiding ALND on relapse and survival rate in cN+ patients, turned ycN0 (clinically) and ypN1mi (pathologically) after NAC.

Materials and methods: This is a non-controlled clinical study designed as a non-inferiority study to verify if the avoidance of ALND in ypN1mi patients after NAC does not involve a significant worsening of survival or locoregional or distant relapse risk compared to ypN0 patients, in which the avoidance of ALND actually represents the standard treatment. Patients with macrometastatic SLN (ypN≥1) after NAC subjected to ALND as a standard procedure represents an internal control group for the demonstrated worse prognosis compared to ypN0 and ypN1mi patients. This study includes patients with cN+ lymph nodes assessed in the initial diagnosis, resulted negative (with clinical and instrumental studies) after NAC. On the base of histopathologic definitive evaluation on harvested sentinel lymph nodes, patients will be allocated in one of the two groups (standard or experimental). Group 1 (experimental) will include patients with micrometastatic SLN or micrometastatic parasentinel lymph node (ypN1mi), in which ALND will not be performed. Group 2 (standard) will include patients with negative SLN or SLN with ITC in it (ypN0/ypN0(i+)). ALND will not be performed in these patients. Patients with macrometastatic SLN or another macrometastatic lymph node (ypN≥1) will be included in a third internal control group (group 3) not utilized in statistical comparison with the other two groups, but finalized to the evaluation of the case study’s appropriateness. In these patients, standard ALND will be performed. Patients enrolling in the study protocol will last 3 years. Patients should be studied for at least 5 years with clinical and instrumental follow-up periodic controls, prevised from actual standard guidelines.

Endpoints: The primary endpoint of the study is the disease free survival rate (DFS) and will be evaluated from the entry date in the study to the date of the last contact, the date of the distant or locoregional relapse, or the date of death for any cause. Secondary endpoints are overall survival (OS), locoregional disease-free survival (LRDFS) and distant disease-free survival (DDFS)

Citation Format: Corrado Tinterri, Emilia Marrazzo, Wolfgang Gatzemeier, Erika Barbieri, Andrea Sagona, Alberto Bottini, Alberto Testori, Valentina Errico, Giuseppe Canavese. Neonod Study: Conservation of axillary lymph nodes in the presence of micrometastases in the sentinel lymph node if cN- After neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT3-01-03.

Abstract OT3-01-02: Preservation of axillary lymph nodes compared to complete dissection in T1-T2 breast cancer patients presenting 1-2 metastatic sentinel lymph nodes: A multicenter randomized clinical trial. Sinodar One Study

Introduction Sentinel lymph node (SLN) staging is currently used to avoid complete axillary lymph node dissection (ALND) in breast cancer (BC) patients with negative SLNs without jeopardizing survival or regional control. International guidelines keep recommending ALND in the presence of positive (+) SLNs. However SLN is the only site of axillary metastasis (MTS) in many cases (60%). Retrospective studies have also shown a low risk of locoregional relapse in patients with SLNs+ not receiving ALND.This latter finding was recently confirmed in a randomized trial comparing SLN biopsy (SLNB) alone with SLNB followed by ALND in patients with 1-2 SLNs+. However the observation of both similar relapse rate and survival in the 2 arms and the conclusion of a non-inferiority of SLNB compared to ALND require cautiousness because of some study limitations: premature enrollment cessation due to death rate lower than expected, short follow-up (6 years), small tumor size (≤2cm in 70% of cases), frequent presence of only microMTS in SLN (40%), prevalent use of “whole breast” adjuvant radiotherapy (&gt;90%) which irradiates the breast but also the I° axillary level, thereby contributing to the low rate of regional relapse in the SLNB arm due to lymph node sterilization. Consequently further randomized trials with more precise selection criteria based on homogeneous clinico-pathological features and with longer follow-up are needed to confirm that performing only SLNB does not affect survival or relapse risk in patients with 1-2 SLNs+. Materials and Methods Primary and secondary aims of the present 2-arm randomized trial are to assess whether ALND omission in BC patients with 1-2 SLNs+ is associated with worse survival and/or increased rate of regional/distant relapse, respectively, thus evaluating whether SLNB is or is not inferior to ALND. Patients receive either conservative surgery or mastectomy and radiotherapy. They all undergo intraoperative SLNB and SLN evaluation, and are randomly assigned to either further dissection of level I-II axillary lymph nodes (standard ALND arm) or absence of any axillary surgery (experimental SLNB arm). According to International Guidelines post-surgery treatments. Eligibility criteria are: age 40-75 years; primary invasive T1-T2 tumor; axillary nodes clinically N0; no more than 2 SLNs presenting macroMTS at intraoperative or definitive histological evaluation; no distant MTS; no neoadjuvant therapy; no previous invasive BC, signed informed consent. Exclusion criteria are: in situ, inflammatory, contralateral BC; presence of only microMTS in the SLN+; pregnancy or breast feeding; comorbidity impeding adjuvant therapy. Follow-up controls foresee: clinical examination every 6 months for 5 years and yearly thereafter; annual mammography and breast echography; annual axillary echography for patients in the SLNB arm; additional laboratory and instrumental surveys in case of suspected onset of distant MTS. The primary endpoint is overall survival (OS). Secondary endpoints are disease-free survival (DFS) referring to distant MTS and to locoregional (ipsilateral breast or axillary, internal mammary or sopraclaveolar lymph nodes) disease recurrence. All analyses are performed both on all patients according to the Intention-To-Treat principle and excluding those patients who did not receive the axillary treatment randomly assigned.

Citation Format: Corrado Tinterri, Emilia Marrazzo, Federico Frusone, Wolfgang Gatzemeier, Erika Barbieri, Andrea Sagona, Alberto Bottini, Valentina Errico, Alberto Testori, Giuseppe Canavese. Preservation of axillary lymph nodes compared to complete dissection in T1-T2 breast cancer patients presenting 1-2 metastatic sentinel lymph nodes: A multicenter randomized clinical trial. Sinodar One Study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT3-01-02.

Mucinous breast cancer: A narrative review of the literature and a retrospective tertiary single-centre analysis

Mucinous carcinoma (MC) is a rare breast cancer characterized by the presence of large extracellular mucin amount. Two main subtypes can be distinguished: pure (PMC) and mixed (MMC). We conducted a retrospective MC analysis in our prospective maintained database, calculating disease-free survival (DFS) and 5-year overall survival (OS). We found a global 92.1% OS (higher in MMC group and statistically significative) and a DFS of 95.3% (higher in MMC group but not statistically significative).

Hypofractionated volumetric modulated arc therapy in ductal carcinoma in situ: toxicity and cosmetic outcome from a prospective series

OBJECTIVE

Hypofractionated radiotherapy in early stage breast cancer is an effective adjuvant treatment, but there is a lack of randomized data for patients with ductal carcinoma in situ (DCIS). The aim of this study is the evaluation of skin toxicity and cosmesis, and early clinical outcome of DCIS patients enrolled in an institutional Phase II trial of hypofractionated breast irradiation.

METHODS

137 DCIS patients were enrolled in the trial. All patients underwent volumetric modulated arc therapy (VMAT) to the whole breast with a total dose of 40.5 Gy in 15 fractions over 3 weeks, without tumour bed boost. Acute and late skin toxicities were recorded. Cosmetic outcomes were assessed as excellent/good or fair/poor. Early clinical outcome was reported.

RESULTS

Median age was 58 y.o. (range 30-86). The median follow-up time was 22 months (range 6-45). At the end of the radiotherapy, skin toxicity was grade G1 in 56% of the patients, G2 in 15%, no patients presented G3 toxicity. In the range of 3-9 months of follow-up, the skin toxicity was G1 in 28% of patients, no G2-G3 cases; cosmetic outcome was good/excellent in 95% of patients. In the follow-up interval of 9-24 months, the skin toxicity was G1 in 12% of patients, no G2-G3 toxicity; cosmetic outcome was good/excellent in 96% of patients. After an early evaluation of clinical outcomes, 5 patients (3.6%) presented an in-breast recurrence.

CONCLUSION

Hypofractionated radiotherapy using VMAT is a viable option for DCIS. A longer follow-up is needed to assess clinical outcomes and late toxicity. Advances in knowledge: The use of hypofractionated VMAT is dosimetrically feasible for treating breast DCIS.

Can Axillary and Supraclavicular Radiotherapy be Avoided after Breast-Conserving Surgery and Axillary Dissection in Women with Multiple Involved Axillary Nodes?: Experience at the European Institute of Oncology

Aims and background

Although some guidelines recommend adjuvant radiotherapy (RT) to the axilla and supraclavicular nodes if 4 or more axillary nodes are involved, the current practice at our Institute is not to irradiate the axilla but to perform complete axillary dissection in which all 3 Berg levels are removed. We performed a retrospective analysis of patients with 4 or more axillary nodes involved and sufficient follow-up to provide indications as to whether our current treatment is adequate.

Methods

We retrospectively analyzed 287 T1–T3 patients with a median follow-up of 5 years and 4 or more involved nodes treated by quadrantectomy and breast RT but no axillary RT; supraclavicular RT was given only when prognostic factors were unfavorable.

Results

A total of 170 (59.2%) patients did not receive supraclavicular RT, while 117 (40.8%) patients received supraclavicular irradiation. No patient received axillary RT. After a median follow-up of 5 years (range, 4–105 months), 4.7% had died and 13.5% had developed distant metastases in the no supraclavicular RT group, compared to 12.0% dead (P = 0.028 log rank) and 24.8% (P = 0.201 log rank) in the supraclavicular RT group. No patients with supraclavicular RT developed supraclavicular metastases compared to 4 in the no supraclavicular RT group. There were no axillary recurrences.

Conclusions

Complete axillary dissection appears adequate treatment in patients with 4 or more involved nodes. The low breast recurrence rate also suggests that breast conservation is adequate treatment in such patients. Supraclavicular RT appears to reduce the number of supraclavicular metastases but confers no survival advantage. Although a small number of cases were examined in this retrospective single-center series, all received highly uniform treatment.

[18F]FDG PET/CT features for the molecular characterization of primary breast tumors

PURPOSE

The aim of this study was to evaluate the role of imaging features derived from [¹⁸F]FDG-PET/CT to provide in vivo characterization of breast cancer (BC).

METHODS

Images from 43 patients with a first diagnosis of BC were reviewed. Images were acquired before any treatment. Histological data were derived from pretreatment biopsy or surgical histological specimen; these included tumor type, grade, ER and PgR receptor status, lymphovascular invasion, Ki67 index, HER2 status, and molecular subtype. Standard parameters (SUV_mean, TLG, MTV) and advanced imaging features (histogram-based and shape and size features) were evaluated. Univariate analysis, hierarchical clustering analysis, and exact Fisher's test were used for statistical analysis of data. Imaging-derived metrics were reduced evaluating the mutual correlation within group of features as well as the mutual correlation between groups of features to form a signature.

RESULTS

A significant correlation was found between some advanced imaging features and the histological type. Different molecular subtypes were characterized by different values of two histogram-based features (median and energy). A significant association was observed between the imaging signature and luminal A and luminal B HER2 negative molecular subtype and also when considering luminal A, luminal B HER2-negative and HER2-positive groups. Similar results were found between the signature and all five molecular subtypes and also when considering the histological types of BC.

CONCLUSIONS

Our results suggest a complementary role of standard PET imaging parameters and advanced imaging features for the in vivo biological characterization of BC lesions.

Potential impact of the 70-gene signature in the choice of adjuvant systemic treatment for ER positive, HER2 negative tumors: a single institution experience

PURPOSE

We investigated in a single institution series of 124 women with operable breast cancer whether tumor clinicopathological features could predict the 70-gene signature (Mammaprint, MP) results, and whether MP results could help to make decisions for the use of chemotherapy (CT) in patients (pts) with ER positive breast cancer beyond recommendations of international guidelines.

RESULTS

Among the 68 ER/PgR positive, HER2 negative tumors, Ki-67 ≥ 20% was the only significant predictor of a high risk-MP among standard clinicopathological features. In candidates for endocrine therapy with undetermined benefit from CT according to international guidelines, MP results would have led to different treatment decisions in 13/46 (28%) and in 20/68 (29%) pts according to NCCN and St. Gallen recommendations, respectively.

CONCLUSIONS

Ki-67 independently predicted high risk-MP in ER/PgR positive, HER2 negative tumors. MP results would have led to discordant treatment recommendations in about 30% of cases, generally increasing indication rate for CT. The results of large randomized trials are warranted in order to understand whether we should rely on multigene assays rather than on standard clinicopathological features for treatment decisions.

Unavoidable mastectomy for ipsilateral breast tumour recurrence after conservative surgery: patient outcome

BACKGROUND

In the case of ipsilateral breast tumour recurrence (IBTR) after breast-conserving surgery (BCS), a second conservative surgical approach maybe considered in some motivated patients whereas in others mastectomy is unavoidable.

PATIENTS AND METHODS

From 1997 to 2004, 282 patients presented at the European Institute of Oncology with an operable invasive IBTR after BCS. One hundred and sixty-one (57%) underwent a second conservative surgery, whereas 121 patients (43%) were given a mastectomy and represent the study population. We investigated the prognosis and determined predictive factors of outcome.

RESULTS

Median time from primary breast cancer to IBTR was 41 months (range 5-213). Recurrences were T2-T4 and/or multifocal in 83 cases (68.6%). With a median follow-up of 5 years after mastectomy, 5-year overall survival (OS) and disease-free survival (DFS) were 73.3% [95% confidence interval (CI) 65.0% to 81.6%] and 50.4% (95% CI 40.9% to 59.8%), respectively. At the multivariate analysis, early onset of IBTR, presence of vascular invasion and Ki67 >or=20 of the recurrent tumour were found to significantly affect both DFS and OS.

CONCLUSIONS

In women who need mastectomy for IBTR, early onset of the relapse, high proliferation index and presence of vascular invasion represent the worst prognostic factors.

The value of radiotherapy on metastatic internal mammary nodes in breast cancer. Results on a large series

The 'regional nodal mapping', is a fundamental step to stage breast carcinoma. In addition to the axillary nodes status, the involvement of internal mammary nodes is an important prognostic factor. Six hundred and sixty-three patients with breast carcinoma, mainly in the inner quadrants, underwent a biopsy of internal mammary nodes. Positive internal mammary nodes were found in 68 out of 663 cases (10.3%) representing 27.2% of all cases with regional node metastases (250). When histologically proven metastases were detected, radiotherapy was administered to the internal mammary nodes chain. In 254 cases, the surgeon's exploration was guided by a gamma probe. Out of these cases, 28 (11.0%) showed metastatic involvement. Out of the other 409 cases, not radioguided, 40 showed positive nodes (9.8%). Patients with internal mammary metastases treated with radiotherapy and appropriate systemic treatment showed an excellent survival (95% at 5 years), a result which is in opposition to the previous experience, which stated that invasion of internal mammary nodes is an ominous prognostic sign. We assume that this excellent result is due to radiotherapy to internal mammary nodes and we propose that exploration of internal mammary nodes should be part of the staging process of carcinomas of the medial part of the breast.

A rare association of synchronous intraductal carcinoma of the breast and invasive carcinoma of ectopic breast tissue of the vulva: case report and literature review

Only 17 cases of breast carcinoma arising in vulvar ectopic mammary tissue have been reported. We present a unique case of synchronous pure intraductal carcinoma of the breast (DCIS) and invasive carcinoma of ectopic breast tissue of the vulva. A 53-year-old woman presented with a 2-cm nodule in left labium major of the vulva. A surgical biopsy revealed an invasive carcinoma of ectopic mammary tissue. The mammography showed irregular microcalcifications of the right breast. The patient underwent left hemivulvectomy, bilateral inguinal sentinel lymph node biopsy, and radioguided breast resection (radioguided occult lesion localization) of the microcalcifications. The definitive histology revealed negative inguinal sentinel nodes, no further residual tumor in the vulva, and a high-grade (grade 3) DCIS in the breast. The synchronous occurrence of primary breast carcinoma and ectopic breast tissue carcinoma in the vulva is an extremely rare finding, only once previously being reported and leading to unsolved problems of differential diagnosis. The presence of a pure DCIS of the breast makes this case really unique, definitively confirming the independent primary origin of both mammary tumors. The inguinal sentinel node biopsy avoided a bilateral inguinal dissection.

A rare association of synchronous intraductal carcinoma of the breast and invasive carcinoma of ectopic breast tissue of the vulva: case report and literature review

Only 17 cases of breast carcinoma arising in vulvar ectopic mammary tissue have been reported. We present a unique case of synchronous pure intraductal carcinoma of the breast (DCIS) and invasive carcinoma of ectopic breast tissue of the vulva. A 53-year-old woman presented with a 2-cm nodule in left labium major of the vulva. A surgical biopsy revealed an invasive carcinoma of ectopic mammary tissue. The mammography showed irregular microcalcifications of the right breast. The patient underwent left hemivulvectomy, bilateral inguinal sentinel lymph node biopsy, and radioguided breast resection (radioguided occult lesion localization) of the microcalcifications. The definitive histology revealed negative inguinal sentinel nodes, no further residual tumor in the vulva, and a high-grade (grade 3) DCIS in the breast. The synchronous occurrence of primary breast carcinoma and ectopic breast tissue carcinoma in the vulva is an extremely rare finding, only once previously being reported and leading to unsolved problems of differential diagnosis. The presence of a pure DCIS of the breast makes this case really unique, definitively confirming the independent primary origin of both mammary tumors. The inguinal sentinel node biopsy avoided a bilateral inguinal dissection.