Time to Cancer Treatment and Chemotherapy Relative Dose Intensity for Patients With Breast Cancer Living With HIV

Importance Patients with breast cancer and comorbid HIV experience higher mortality than other patients with breast cancer.Objective To compare time to cancer treatment initiation and relative dose intensity (RDI) of neoadjuvant and adjuvant chemotherapy among patients with breast cancer with vs without HIV.Design, Setting, and Participants A retrospective, matched cohort study enrolled women who received a diagnosis of breast cancer from January 1, 2000, through December 31, 2018. The electronic medical records of 3 urban, academic cancer centers were searched for women with confirmed HIV infection prior to or simultaneous with diagnosis of stage I to III breast cancer. Tumor registry data were used to identify 2 control patients with breast cancer without HIV for each participant with HIV, matching for study site, stage, and year of cancer diagnosis. Statistical analysis was performed from December 2022 to October 2023.Exposure HIV infection detected before or within 90 days of participants' breast cancer diagnosis.Main Outcomes and Measures The primary outcome was time to breast cancer treatment initiation, defined as the number of days between cancer diagnosis and first treatment. The secondary outcome was overall RDI for patients who received chemotherapy. These outcomes were compared by HIV status using Cox proportional hazards regression and linear regression modeling, respectively, adjusting for confounding demographic and clinical factors. Exploratory outcomes included instances of anemia, neutropenia, thrombocytopenia, and liver function test result abnormalities during chemotherapy, which were compared using Fisher exact tests.Results The study enrolled 66 women with comorbid breast cancer and HIV (median age, 51.1 years [IQR, 45.7-58.2 years]) and 132 with breast cancer alone (median age, 53.9 years [IQR, 47.0-62.5 years]). The median time to first cancer treatment was not significantly higher among patients with HIV than those without (48.5 days [IQR, 32.0-67.0 days] vs 42.5 days [IQR, 25.0-59.0 days]; adjusted hazard ratio, 0.78, 95% CI, 0.55-1.12). Among the 36 women with HIV and 62 women without HIV who received chemotherapy, the median overall RDI was lower for those with HIV vs without HIV (0.87 [IQR, 0.74-0.97] vs 0.96 [IQR, 0.88-1.00]; adjusted P = .01). Grade 3 or higher neutropenia during chemotherapy occurred among more women with HIV than those without HIV (13 of 36 [36.1%] vs 5 of 58 [8.6%]).Conclusions and Relevance This matched cohort study suggests that patients with breast cancer and HIV may have experienced reduced adjuvant chemotherapy RDI, reflecting greater dose reductions, delays, or discontinuation. Strategies for supporting this vulnerable population during chemotherapy treatment are necessary.