Background Breast cancer (BC) is the most common cancer among women and the second most common cause of cancer-related mortality among women. Much attention has been paid to factors that increase the risk of developing BC. Among these are weight, typically defined by body mass index (BMI), and race. Elevated BMI has not only been shown to increase the risk of BC in some patients but has also been associated with increased rates of hormone receptor (HR) positive BC, particularly among postmenopausal patients. In premenopausal patients, an inverse relationship has been established between obesity and BC. In fact, a 2008 meta-analysis of obesity and malignancy evaluated almost 8,000 cases of premenopausal BC and showed a BC risk reduction of 8% for every 5 kg/m2. However, this study was not inclusive of African American (AA) patients. AA women are more likely to be obese than any other racial group in the US. They are also at higher risk of aggressive breast cancers, and at an earlier age. We sought to evaluate the relative risk of breast cancer diagnosis among obese vs nonobese patients of different races, as well as the rate of HR positivity in patients diagnosed with BC. Methods BMI, age, and self-declared race were collected from the electronic health record for all female patients presenting to our health system located in Louisiana and Mississippi between 2012 and 2022. This same data was collected for female patients who were diagnosed with BC in the same time period (n=9123), as well as HR positivity vs HR negativity. Patients less than 50 years old were considered premenopausal, and patients greater than 50 years old were considered postmenopausal. BMI greater than 30 was used to define obesity. The relative risk of BC was calculated for demographic groups according to premenopausal or postmenopausal status, White or Black/African American race, and BMI less than or greater than 30. The relative risk of HR positive BC was calculated among the same demographic groups. Discussion Data collected across the largest health system in Louisiana and Mississippi shows that a higher BMI is linked to an increased risk of BC, regardless of age or race. This was seen across both stratifications and was statistically significant except in postmenopausal AA women. This is contrary to what is frequently published in the literature that premenopausal obesity is protective against BC. Additionally, this data demonstrates that there is not a link between obesity and HR+ BC. This data did show that obesity in younger white patients may be protective against HR+ BC, which is aligned with prior research. Conclusion The association between obesity and BC incidence has been well-described in the literature, primarily in the postmenopausal setting. This large, retrospective analysis confirms that association, but also shows a strong association in premenopausal patients. Unlike other studies, this review did not show an association between obesity and HR positivity, and additionally did not show significant differences between AA patients and White patients. This provides needed insight into the inequities faced by AA women with BC. Further studies should be done to evaluate the association of socioeconomic status with BC subtypes. Table 1: Breast cancer cases (5/1/2012-5/1/2022) among women by BMI, age group, and race Table 2: Hormone receptor positivity (5/1/2012-5/1/2022) among women with breast cancer by BMI, age group, and race Citation Format: Victoria Chung, Ruby Maini, Rabia Cattie, Susan Olet, Melanie Sheen. PD12-04 Impact of Race and Body Mass Index on Breast Cancer Diagnoses [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 PD12-04.

Pathologic Complete Response in Triple Negative Breast Cancer of Black vs White Patients in the Post-Keynote 522 Era Melanie Sheen MD, Victoria Chung DO, Ruby Maini MD, Michael Duggan BS, Julia Levy BS Background Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer that lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) gene amplification. Women with TNBC have worse survival outcomes and increased rates of relapse and distant metastasis as compared to women with non-TNBC. Treatment of TNBC has recently been focused on neoadjuvant chemotherapy (NACT) with a goal of achieving a pathologic complete response (pCR) which is associated with longer event-free survival and overall survival. The KEYNOTE-522 trial was presented at the San Antonio Breast Cancer Symposium in December 2019 and found that patients who received pembrolizumab, an anti–programmed death 1 (PD-1) monoclonal antibody, plus NACT were more likely to achieve pCR than women who received placebo plus NACT. On July 26, 2021, the FDA approved the use of pembrolizumab in combination with NACT for high risk, early stage TNBC. KEYNOTE-522 did not collect race as a baseline demographic characteristic, and since TNBC disproportionately affects younger women and Black women, confirming the efficacy of achieving pCR in these groups is essential. Further investigation of the factors that may contribute to achieving pCR in women treated with pembrolizumab for TNBC is warranted. We set out to perform a retrospective analysis examining the rates of pCR in Black versus White patients with TNBC since the initial revelation of the KEYNOTE-522 data. Methods This retrospective chart review of a regional health care network included patients who had been diagnosed with Stage II/III TNBC, documented race as Black/African-American or White, and received treatment with pembrolizumab in the NACT setting. Exclusion criteria included ER-positivity, PR-positivity, HER2-positivity, or unknown receptor status, no pembrolizumab in the neoadjuvant setting, absence of documented race, and age < 18 years-old. Data was collected using Epic SlicerDicer program. Results 118 patients met inclusion criteria. 59 (50.0%) were Black/African American, 59 (50.0%) were white. There were 57 (48.3%) patients who had pCR status identified through pathology reports while the remaining 61 (51.7%) are still undergoing NACT awaiting surgery. 34 Black women and 17 white women have not had surgery yet. Of women who underwent surgery, 12 Black women achieved pCR compared to 15 White women. 13 Black women and 16 White women did not have pCR Discussion Analysis of the data demonstrates an equal number of Black and White women receiving NACT with pembrolizumab. Of those women, there was relatively equal number of pCR between Black and White women. This data shows no appreciable difference in outcomes of Black and White women in terms of response to therapy. Conclusion Given the known association of pCR with increased survival, pembrolizumab should be considered in the treatment regimen for both Black and White women with stage II/III TNBC. This retrospective study is limited by a small patient population. Continued data collection is underway and will be updated. Citation Format: Melanie Sheen, Victoria Chung, Ruby Maini, Michael Duggan, Julia Levy. Pathologic Complete Response in Triple Negative Breast Cancer of Black vs White Patients in the Post-Keynote 522 Era [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 P4-06-11.

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