Breast cancer is the second leading cause of cancer death among women living with HIV (WLHIV) with access to ART. In the context of ART coverage exceeding UNAIDS 90-90-90 targets, we sought to prospectively assess the impact of HIV on overall survival of women with breast cancer.
As part of the Thabatse Cancer Cohort, we included women presenting (October 2010 to March 2018) for initial treatment of breast cancer at one of four oncology centers in Botswana. Consenting patients were interviewed, records abstracted, and followed for up to 5 years. The association between HIV infection and all-cause mortality was assessed using a multivariable Cox proportional hazards model including covariates selected a priori: cancer stage, curative versus palliative intent, receptor status, age, and personal income.
A total of 430 women with breast cancer with known HIV status were enrolled (4 women with unknown HIV status excluded), including 135 (31.4%) WLHIV and 295 (68.6%) uninfected women. WLHIV were younger than uninfected women, median 47.5 and 55.5 years, respectively (p<0.001). Among WLHIV, 110 (84%) were on ART prior to cancer diagnosis (median duration 6.8 years) and median CD4 count was 513 cells/μL. Advanced cancer stage (III/IV) was common for both WLHIV (67%) and uninfected women (66%). Immunohistochemistry results were available for 250 women (58%); 154 (62%) women were ER+ and 65 (26%) were triple-negative. Receptor status was similar by HIV status (p=0.89). The majority (69%) received multimodality treatment with curative intent and the proportion did not differ by HIV status (p=0.80). After 847 patient-years of follow-up, 156 women died, including 66 (49%) WLHIV and 90 (31%) uninfected women. Three women (0.7%) were lost to follow-up. The majority of deaths (141, 90%) were attributed to cancer and none to HIV. Two-year survival for WLHIV was lower than those without HIV, 57% and 73%, respectively (see Figure, p<0.001). Findings were similar in adjusted analyses with WLHIV experiencing higher mortality (hazard ratio 1.86, 95%CI 1.33 to 2.61, p<0.001). Cancer stage, treatment intent, and personal income less than $50/month were also inversely predictive of survival (p<0.001 for each).
HIV infection is associated with substantially higher non-AIDS mortality among women with breast cancer. Improved understanding of mechanisms underlying excess mortality could contribute to improved outcomes in the majority female and aging African HIV epidemic.