Abstract P4-03-05: HER2 + Breast Cancer in Afro-Caribbean Women in New York City

Abstract

Abstract Background: Human Epidermal Growth Factor receptor 2 (HER2) protein overexpression and/or amplification positive breast cancer accounts for 14% of breast cancer cases in the United States. The use of anti-HER2 targeted therapy in combination with chemotherapy has resulted in better response rates leading to better outcomes in patients with this breast cancer subtype. Few studies directly investigate breast cancer outcomes in Afro-Caribbean women in the U.S, and fewer studies have investigated HER2 positive (HER2+) disease in this patient group. We describe the clinicopathologic characteristics and outcomes of HER2+ breast cancer in this minority patient group. Methods: This is a retrospective study conducted at Kings County Hospital (KCH), a public hospital in Brooklyn, a New York City borough with the highest population of Afro-Caribbeans in the United States, outside of Miami, Florida. Data of patients diagnosed with breast cancer from 2015-2018 was collected from the hospital’s tumor registry. Clinical and pathologic data was collected and analyzed with descriptive statistics and Chi-square testing. Results: A total of 299 women with breast cancer were screened and 18% (54) had HER2+ disease. 63% (34) of these patients were post-menopausal, with median age 56. 78% self-identified as Afro-Caribbean. 19% (11) of patients reported first- or second-degree relatives with a breast cancer diagnosis, 22% (13) reported first-degree relative with non-breast malignancy. Half of the patients younger < 45 years age reported a positive family history of any type of cancer. 74% of patients presented with Nottingham Grade 3 disease, 31% with localized disease, without lymph node involvement, 52% with regional lymph node involvement, and 17% with distant metastasis. 63% of patients were estrogen receptor (ER) positive and 37% were ER negative. Post-menopausal women presented with higher rates of lymph node involvement at 70.4% vs. 50% in pre-menopausal women (p=0.17). 41% (22) of patients received neoadjuvant chemotherapy while 31% received adjuvant therapy with standard chemotherapy and anti-HER2 targeted treatment. Of the 22 patients who received neoadjuvant treatment, 14% had complete pathologic response, 68% had partial response, and 18% had disease progression. Treatment response to neoadjuvant therapy was independent of lymph node status (90.9% in local disease vs. 85.7% in lymph node involvement, p=0.66). The median progression free survival was 48 months, overall survival at 7 years was not reached, and mortality rate was 16.7%. Conclusions: In our analysis, Afro-Caribbean patients with HER2+ breast cancer presented with high grade tumor, high incidence of regional lymph node involvement, and ER positive tumors. Noteworthy was the presence of strong family history of cancers, suggestive of familial or inherited cancers. Pathologic complete response to neoadjuvant chemotherapy was remarkably less than anticipated, and further research is warranted to study tumor biology and responses to standard HER2 systemic therapies in these patients.