N. Bader1, M. L. Nguyen1, A. Marra2, J. Patel3, N. T. Pfister3, P. R. Patel3, M. W. McDonald4, S. Rudra3, O. Alese1,5, L. McCullough6, J. Wells7, L. Flowers1, C. Gunthel1, and J. Y. Lin8; 1Emory University School of Medicine, Atlanta, GA, 2Winship Cancer Institute at Emory University, Atlanta, GA, 3Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, 4Emory Proton Therapy Center, Atlanta, GA, 5Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University, Atlanta, GA, 6Emory University Rollins School of Public Health, Atlanta, GA, 7Emory University School of Nursing, Atlanta, GA, 8Glenn Family Breast Center, Winship Cancer Institute, Emory University, Atlanta, GA
Purpose/Objective(s): The incidence of anal cancer and anal cancer death continues to rise. People of color (POC) have been underrepresented in prospective clinical trials, including trials that have established anal cancer treatment to include modern radiation therapy (RT) techniques and concurrent chemotherapy. We evaluated our institutional experience to determine if disparities in oncologic outcomes and treatment tolerability exist among POC. Materials/Methods: We performed a retrospective chart review of anal cancer patients who received definitive organ-preserving treatment for localized anal cancer between 2008 and 2020 at a single health system. Outcomes including overall survival (OS), local recurrence-free survival (LRFS), and progression free-survival (PFS) were estimated using the Kaplan-Meier method. Toxicities were scored using the National Cancer Institute-Common Terminology Criteria for Adverse Events v5. Results: Of the 201 consecutively treated patients, 16% were stage I, 24% were stage II, and 58% were stage III. Mean age at diagnosis was 53 years (range 31 – 78 years). The majority (95%) were treated with intensity modulated RT technique and most (98%) patients received concurrent chemotherapy. Median RT dose was 54 Gy (range 45 to 60.2 Gy). Over half (n = 111) had human immunodeficiency virus infection (HIV) at time of cancer diagnosis; among those with HIV, 81% identified as POC. With a median follow-up of 4 years (range 0 – 14.8 years), POC with anal cancer (n = 127) had greater risk of dying than non-Hispanic White patients (n = 72), hazard ratio (HR) = 2.00, confidence interval (CI): 1.10-3.64, p = 0.02. POC were also more likely to have local recurrence compared to non-Hispanic White patients (HR = 2.67, CI 1.10-6.48, p = 0.03). No significant difference was observed with PFS (HR 1.54, CI 0.81-2.93, p = 0.185). Notably, HIV infection was not associated with differences in OS, LRFS, or PFS. The mean age of diagnosis was younger in POC at 50.7 years (standard deviation [SD] 10.4 years) compared to non-Hispanic White patients (58.1 years [SD 7.6 years]). POC were more likely to have prolonged RT course (> 5 missed RT sessions) compared to their non-Hispanic White counterparts, 30% vs 23%, respectively. While most acute and late toxicities were similar between the two groups, POC had higher likelihood of late grade 2 skin toxicities than non-Hispanic White patients, 17% vs 3%, respectively, p < 0.01.
Conclusion: Our study found worse OS and LRFS among POC compared to non-Hispanic white patients. Sustained late skin toxicities and prolonged treatment times were more common among POC. HIV infection was not independently correlated with worse outcomes even though minority race and extended RT course were seen more frequently among the group with HIV infection. Addressing barriers and biases to diagnosis and treatment, as well as inclusion of POC in prospective clinical trials, are urgently needed to optimize treatment and close the disparity gap that POC with anal cancer may face.
