Relative dose intensity and pathologic response rates in HIV-infected and HIV-uninfected breast cancer patients who received neoadjuvant chemotherapy.

Abstract

e19140 Background: HIV-infected (HIV+) breast cancer patients may have significantly worse survival compared to HIV-uninfected (HIV-). If so, identifying the underlying mechanism might lead to effective interventions to reduce the disparity. Relative dose intensity (RDI) < 0.85 has been associated with worse survival outcomes in non-metastatic breast cancer patients. We aimed to determine if RDI of chemotherapy and pathologic complete response (pCR) rates were lower for HIV+ patients who received neoadjuvant chemotherapy (NAC) compared with HIV-. Methods: We conducted a prospective cohort study in newly diagnosed breast cancer patients with locally advanced disease who initiated NAC at Princess Marina Hospital in Botswana between 2/2017 and 9/2019. Clinical and treatment data were collected at baseline and at every treatment visit. Surgical pathology post-NAC was graded as pCR if there was no invasive disease in the breast or lymph nodes. RDI was calculated for each patient, with optimal RDI ≥ 0.85. Dichotomous variables were compared using Fisher’s exact and chi-squared tests; and continuous variables using rank sum tests. Results: 111 patients were enrolled, of whom 84 (75.7%) were HIV-, 26 (23.4%) HIV+ and 1 (0.9%) with unknown status who was excluded from final analysis. HIV+ patients were less likely to receive optimal RDI (0.74 vs. 0.88; p = 0.03). Of the 110 patients 15 (13.6%) were still receiving chemotherapy; 22 (20%) prematurely discontinued chemotherapy of whom 11 (10%) received surgery; 7 (6.4%) completed chemotherapy but had no surgery. 77 (70%) completed surgery which included 11 (10%) with no pathology reports available, 3 (2.7%) inadequate surgical specimens and 63 (57.3%) complete pathology results included in pCR analysis: 1/13 (7.7%) HIV+ patients had a pCR compared to 12/50 (24%) in HIV-(p = 0.27). Conclusions: HIV+ patients were significantly more likely to receive inadequate neoadjuvant chemotherapy dose intensity, and trended towards a lower pCR in this small cohort, which may contribute to adverse treatment outcomes. Further study needed to validate high rate of treatment discontinuation and specific risk factors to inform targeted interventions to improve therapy delivery.