Outcomes for incurable anal cancer according to HIV status.

Abstract

2 Background: The incidence of anal cancer continues to rise in the United States, with an increasing proportion of patients (pts) presenting with incurable/metastatic disease at initial evaluation. An HIV-positive diagnosis is a known risk factor for development of anal cancer and a poor prognostic factor once diagnosed. To date, clinical and oncologic characteristics, as well as patterns of failure, for pts with incurable/metastatic anal cancer associated with an HIV diagnosis remain poorly detailed. Methods: We conducted a retrospective chart review at MD Anderson under an IRB-approved protocol of 136 pts with unresectable and/or metastatic anal cancer. Comparisons in demographic features between persons living with HIV (PLWH; N=35) and persons living without HIV (PWOH; N=101) were performed using a Fisher’s exact test, with the exception of stage at diagnosis and lines of treatment (X 2 test). Median PFS and OS, with 95% confidence intervals (CI), were estimated by the Kaplan-Meier method. Comparisons in survival between PLWH and PWOH were performed by log-rank test. A two-sided p-value < 0.05 was considered statistically significant. Results: Median CD4 count among PLWH was 182 (range, 36-1345). PLWH were younger (median age, 50 vs 58 years) and more likely to be male (83% vs 18%), non-Caucasian (57% vs 7%), unmarried/single (74% vs 27%), and LGBTQ+ (100% vs 4%) relative to PWOH (p < 0.001 for all). PLWH were more likely to develop locally recurrent, unresectable anal cancers that did not metastasize (83% vs 11%, p< 0.001). A higher proportion of PLWH received no systemic therapy for incurable anal cancer (31% vs 0%, p< 0.001). For those who did receive treatment, the median number of treatment lines was lower (1 vs 2, p< 0.001) for PLWH. PFS was shorter in the first (6.1 vs 8.9 months; hazard ratio (HR) 2.3, 95% CI 1.4-3.8; p=0.001) and second lines (2.4 vs 4.3 months; HR 2.9, 95% CI 1.4-6.1; p=0.003) of palliative systemic therapy for PLWH relative to PWOH. OS for incurable anal cancer was significantly shorter for PLWH (8.0 vs 31.9 months; HR 5.7, 95% CI 3.5-9.4; p< .001). Conclusions: To our knowledge, we present the first series detailing inferior PFS and lower metastatic potential for patients with incurable anal cancer according to HIV-positive status. Shortened survival may be attributed not only to key differences in patient demographic but also a unique clinical biology, manifesting as non-metastasizing, locally recurrent/unresectable anal cancer. Further studies to identify biomarkers in anal cancer which differ for PLWH and PWOH are warranted.