Racial/Ethnic Disparities in Pathologic Complete Response and Overall Survival in Patients With Triple-Negative Breast Cancer Treated With Neoadjuvant Chemotherapy

PURPOSE

Black women have higher rates of death from triple-negative breast cancer (TNBC) than White women. We hypothesized that pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) and overall survival (OS) may vary by race/ethnicity in patients with TNBC.

METHODS

We identified women 18 years and older with stage I-III TNBC who received NAC followed by surgery from the National Cancer Database (2010-2019). We excluded patients without race/ethnicity or pathology data. Primary outcomes were pCR rates and OS on the basis of race/ethnicity.

RESULTS

Forty thousand eight hundred ninety women with TNBC met inclusion criteria (median age [IQR], 53 [44-61] years): 26,150 Non-Hispanic White (64%, NHW), 9,672 Non-Hispanic Black (23.7%, NHB), 3,267 Hispanic (8%), 1,368 Non-Hispanic Asian (3.3%, NHA), and 433 Non-Hispanic Other (1.1%, NHO) patients. Overall, 29.8% demonstrated pCR (NHW: 30.5%, NHB: 27%, Hispanic: 32.6%, NHA: 28.8%, NHO: 29.8%). Unadjusted OS was significantly higher for those with pCR compared with those with residual disease (5-year OS, 0.917 [95% CI, 0.911 to 0.923] v 0.667 [95% CI, 0.661 to 0.673], log-rank P < .001), and this association persisted after adjustment for demographic and tumor factors. The effect of achieving pCR on OS did not differ by race/ethnicity (interaction P = .10). However, NHB patients were less likely (odds ratio [OR], 0.89 [95% CI, 0.83 to 0.95], P = .001) and Hispanic patients were more likely (OR, 1.19 [95% CI, 1.08 to 1.31], P = .001) to achieve pCR than NHW patients. After adjustment for patient and disease factors, including achievement of pCR, Hispanic (hazard ratio [HR], 0.76 [95% CI, 0.69 to 0.85], P < .001) and NHA (HR, 0.64 [95% CI, 0.55 to 0.75], P < .001) race/ethnicity remained associated with OS.

CONCLUSION

Odds of achieving pCR and OS in patients with TNBC appear to be associated with race/ethnicity. Additional research is necessary to understand how race/ethnicity is associated with rates of pCR and OS, whether related to socioeconomic factors or biologic variables, or both.

Omission of Axillary Dissection Following Nodal Downstaging With Neoadjuvant Chemotherapy

Importance

Data on oncological outcomes after omission of axillary lymph node dissection (ALND) in patients with breast cancer that downstages from node positive to negative with neoadjuvant chemotherapy are sparse. Additionally, the best axillary surgical staging technique in this scenario is unknown.

Objective

To investigate oncological outcomes after sentinel lymph node biopsy (SLNB) with dual-tracer mapping or targeted axillary dissection (TAD), which combines SLNB with localization and retrieval of the clipped lymph node.

Design, Setting, and Participants

In this multicenter retrospective cohort study that was conducted at 25 centers in 11 countries, 1144 patients with consecutive stage II to III biopsy-proven node-positive breast cancer were included between April 2013 and December 2020. The cumulative incidence rates of axillary, locoregional, and any invasive (locoregional or distant) recurrence were determined by competing risk analysis.

Exposure

Omission of ALND after SLNB or TAD.

Main Outcomes and Measures

The primary end points were the 3-year and 5-year rates of any axillary recurrence. Secondary end points included locoregional recurrence, any invasive (locoregional and distant) recurrence, and the number of lymph nodes removed.

Results

A total of 1144 patients (median [IQR] age, 50 [41-59] years; 78 [6.8%] Asian, 105 [9.2%] Black, 102 [8.9%] Hispanic, and 816 [71.0%] White individuals; 666 SLNB [58.2%] and 478 TAD [41.8%]) were included. A total of 1060 patients (93%) had N1 disease, 619 (54%) had ERBB2 (formerly HER2)-positive illness, and 758 (66%) had a breast pathologic complete response. TAD patients were more likely to receive nodal radiation therapy (85% vs 78%; P = .01). The clipped node was successfully retrieved in 97% of TAD cases and 86% of SLNB cases (without localization). The mean (SD) number of sentinel lymph nodes retrieved was 3 (2) vs 4 (2) (P < .001), and the mean (SD) number of total lymph nodes removed was 3.95 (1.97) vs 4.44 (2.04) (P < .001) in the TAD and SLNB groups, respectively. The 5-year rates of any axillary, locoregional, and any invasive recurrence in the entire cohort were 1.0% (95% CI, 0.49%-2.0%), 2.7% (95% CI, 1.6%-4.1%), and 10% (95% CI, 8.3%-13%), respectively. The 3-year cumulative incidence of axillary recurrence did not differ between TAD and SLNB (0.5% vs 0.8%; P = .55).

Conclusions and Relevance

The results of this cohort study showed that axillary recurrence was rare in this setting and was not significantly lower after TAD vs SLNB. These results support omission of ALND in this population.

Anatomy Versus Biology: What Guides Chemotherapy Decisions in Older Patients With Breast Cancer?

INTRODUCTION

With the increasing utilization of genomic assays, such as the Oncotype DX recurrence score (RS), the relevance of anatomic staging has been questioned for select older patients with breast cancer. We sought to evaluate differences in chemotherapy receipt and/or survival among older patients based on RS and sentinel lymph node biopsy (SLNB) receipt/result.

METHODS

Patients aged ≥ 65 diagnosed with pT1-2/cN0/M0 hormone-receptor-positive (HR+)/HER2-breast cancer (2010-2019) were selected from the National Cancer Database. Logistic regression was used to identify factors associated with chemotherapy receipt. Cox proportional hazards models were used to estimate the association of RS/SLNB group with overall survival. A cost-benefit study was also performed.

RESULTS

Of the 75,428 patients included, the majority had an intermediate RS (58.2% versus 27.9% low, 13.8% high) and were SLNB- (85.1% versus 11.6% SLNB+, 3.3% none). Chemotherapy was recommended for 13,442 patients (17.8%). After adjustment, chemotherapy receipt was more likely with higher RS and SLNB+. After adjustment, SLNB receipt/result was only associated with overall survival among those with an intermediate RS. However, returning to the OR for SLNB is not cost-effective.

CONCLUSIONS

SLNB receipt/result was associated with survival for those with an intermediate RS, but not a low or high RS, suggesting that an SLNB may indeed be unnecessary for select older patients with breast cancer.

Axillary nodal disease burden is not associated with an elevated 21-gene recurrence score in post-menopausal women presenting with a clinically negative axilla

BACKGROUND

The predictive and prognostic value of the recurrence score (RS) has emphasized the importance of tumor biology and has reduced the prognostic implications of limited nodal burden in post-menopausal women with HR+/HER2-invasive breast cancer (IBC). It is unclear whether routine axillary staging has a continued role in the management of small, clinically node negative (cN0) HR+/HER2- IBC. We sought to estimate the association of RS with pN stage.

METHODS

Patients >50yo diagnosed with cN0, HR+/HER2- IBC (2015-2019) with an available RS were identified from the National Cancer Database. The clinicopathologic characteristics and rates of pN-stage (pN0, pN1, pN2/3) were compared for RS of ≤25 vs. >25.

RESULTS

The median patient age was 64.1 (IQR 58-69) and the majority (75%) of tumors displayed ductal histology. Most (81.6%) were cT1 on presentation and pT1 (74.7%) on final pathology. There were 130,568 (86.2%) with a RS ​≤ ​25 and 20,879 (13.8%) with a RS ​> ​25. On final pathology, 128,995 (85.2%) were pN0 and 21,991 (14.5%) pN1. Of the pN1, 2699 (12.3%) yielded a RS ​> ​25. There were 461 (0.3%) patients with pN2-pN3 disease. Of those, 57 (12.4%) had RS ​> ​25.

CONCLUSION

In our analysis, pN0 and pN1 tumors are biologically similar by gene expression assay in postmenopausal patients with similar proportions of high RS. These data support the notion that tumor biology examined via RS may have more prognostic and predictive value than metastatic dissemination to limited lymph nodes. These findings support the ongoing evaluation of routine axillary staging in postmenopausal patients with HR+/HER2- IBC.

Abstract P3-05-20: Low 21-Gene Recurrence Score Is Not Associated with a High Axillary Nodal Burden in Post-Menopausal Women Presenting with a Clinically Negative Axilla

Background: The predictive and prognostic value of the 21-gene recurrence score (RS) has emphasized the importance of tumor biology and minimized the credence of a limited (1-3 positive) nodal burden. The practice changing results of RxPonder demonstrated that post-menopausal women with 1-3 positive lymph nodes (pN1) and a RS of ≤25 did not necessarily benefit from adjuvant chemotherapy. Given that RS influences adjuvant therapy decision-making more significantly than nodal status, it is unclear whether axillary staging with sentinel lymph node biopsy (SLNB) has a continued role in the surgical care of post-menopausal patients otherwise presenting with early stage, clinically node negative (cN0) hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) invasive breast cancer. In this context, the de-escalation of axillary staging, especially in the presence of a low RS, is an area of active investigation. To help elucidate this further, we sought to estimate the association of RS with pathologic nodal stage.

Methods: Using the 2004-2019 National Cancer Database (NCDB) Patient User File (2022 release), we evaluated the association of RS with the incidence of pN0, pN1 and pN2-3 disease. Only female patients diagnosed who were age 50 and older with HR+/HER2- invasive breast cancer were eligible, and only those presenting with cT1-T2N0 who underwent upfront surgery with a SLNB comprised our study population. Those with Oncotype DX testing performed with an available RS were included. Given the limitations within the dataset, age 50 and over was selected as a surrogate for post-menopausal status. Categorical variables were compared between RS groups (≤25 vs. &gt;25) using chi-square tests and continuous variables were compared using t-tests. A logistic regression analysis was performed to estimate the association between RS (≤25 vs. &gt;25) and nodal burden (pN2-3 vs pN0-1).

Results: There were 151,447 patients with an invasive breast cancer diagnosis between 2015 and 2019 who met inclusion criteria. The average age at diagnosis was 64.1 (IQR 58-69) and almost 75% of tumors displayed ductal histology. There were 130,568 (86.2%) patients with a RS≤25 and 20,879 (13.8%) with a RS &gt;25. On final pathology, 85.2% were pN0 and 14.8% were pN1-3. For those with a RS ≤25, 84.9% were pN0, 14.8% were pN1 and 0.3% were pN2-3. For those with a RS &gt;25, 86.8% were pN0, 12.9% were pN1 and 0.3% were pN2-3. Overall, 14.5% demonstrated pN1 disease, of which 12.3% yielded a RS &gt;25. Of the 461 patients with pN2-3 disease for whom RS was available, 12.4% (57 patients) had RS &gt;25. After adjustment, RS &gt;25 was associated with reduced incidence of pN2-3 compared to pN0-1 (OR=0.64, 95% CI 0.47-0.87, p=0.004).

Conclusion: In this population of post-menopausal patients with cT1-T2N0, HR+/HER2- invasive breast cancer and an available RS, almost 86% displayed pN0 or pN1 disease in conjunction with a RS ≤25. Based on the current available literature, less than 5% of cT1-2N0 patients are thought to harbor &gt;pN1 disease. These data add further support, suggesting that this patient population is unlikely to harbor a higher than limited nodal burden given a clinically negative axilla. Though less than 0.5% of the studied patient population demonstrated pN2-3 disease, an important caveat to make is that these patients would not have met criteria for RS, and it’s likely this low number reflects the absence of testing. Given that RS has not been validated for this higher nodal stage, we cannot make recommendations to omit axillary surgery in this cohort of patients. The data presented here provides further rationale for the two large prospective studies addressing whether SLNB could be eliminated in patients with otherwise small HR+/HER2- tumors which are currently ongoing.

Table 1: Pathologic Nodal Staging Based on Recurrence Score

Citation Format: Astrid Botty van den Bruele, Morgan Paul, Samantha M. Thomas, Sarah L. Sammons, Maggie L. DiNome, Jennifer K. Plichta, Akiko Chiba, Laura H. Rosenberger, E Shelley Hwang. Low 21-Gene Recurrence Score Is Not Associated with a High Axillary Nodal Burden in Post-Menopausal Women Presenting with a Clinically Negative Axilla [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 P3-05-20.

The Influence of Body Mass Index on the Histopathology and Outcomes of Patients Diagnosed with Atypical Breast Lesions

BACKGROUND

Multiple studies have demonstrated a link between obesity and breast cancer; however, the potential association between obesity and atypical high-risk breast lesions has not been well characterized. We sought to evaluate the characteristics and clinical outcomes of patients with breast atypia based on a woman's body mass index (BMI).

METHODS

We retrospectively identified adult women diagnosed with atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and/or lobular carcinoma in situ (LCIS) at a single institution from 2008 to 2017. BMI groups were defined as a BMI 18.5 to < 30 or BMI ≥ 30 (obese). Adjusted logistic regression was used to estimate the association of BMI group with the odds of (1) upstage to cancer after atypia on needle biopsy, and (2) subsequent diagnosis of breast cancer.

RESULTS

Breast atypia was identified in 503 patients (most advanced atypia: 74.8% ADH, 4.6% ALH, 20.7% LCIS), and 41% of these patients were classified as obese. After adjustment, BMI group was not associated with upstage to breast cancer at surgical excision following needle biopsy (p = 0.16) or development of a subsequent breast cancer (p = 0.08). For those upstaged to breast cancer at the time of surgical excision, or those who developed a subsequent malignancy, tumor subtype, grade and stage were not associated with BMI group (p > 0.05).

CONCLUSION

In a large cohort of patients diagnosed with atypical breast histology, the risk of upstaging and/or subsequent progression to a breast malignancy was not associated with BMI. Factors other than obesity may influence breast cancer risk.

Mobile mammography in New York City: analysis of 32,350 women utilizing a screening mammogram program

Mobile mammography vans (mammovans) may help close the gap to access of breast cancer screening by providing resources to underserved communities. Minimal data exists on the populations served, the ability of mammovans to reach underserved populations, and the outcomes of participants. We sought to determine the demographic characteristics, number of breast cancers diagnosed, and number of women who used the American Italian Cancer Foundation (AICF) Mobile, No-Cost Breast Cancer Screening Program within the five boroughs of New York City. Data were collected by the AICF from 2014 to 2019 on a voluntary basis from participants at each screening location. Women aged 40 to 79 years who had not had a mammogram in the previous 12 months were invited to participate. Each participant underwent a clinical breast exam by a nurse practitioner followed by a screening mammogram. Images were read by a board-certified radiologist contracted by the AICF from Multi Diagnostic Services. There were 32,350 participants in this study. Sixty-three percent reported an annual household income ≤$25,000, and 30% did not have health insurance. More than half of participants identified as either African American (28%) or Hispanic (27%). Additional testing was performed for 5359 women found to have abnormal results on screening. In total, 68 cases of breast cancer were detected. Breast cancer disparities are multifactorial, with the greatest factor being limited access to care. Mobile, no-cost mammogram screening programs show great promise in helping to close the gap to screening access.