Anal carcinoma is an increasingly significant public health issue, mainly caused by infection with high-risk human papillomavirus (HPV). Despite this, there is limited data on the distribution of HPV genotypes and their associated clinicopathological characteristics among patients in Tanzania. This study aimed to describe the range of HPV genotypes and to explore their relationship with clinical and pathological features in patients diagnosed with anal carcinoma in Northwestern Tanzania.

This longitudinal, analytical, laboratory-based study was conducted at Bugando Medical Centre between 30th April 2023 and 02nd January 2025. A total of 60 formalin-fixed paraffin-embedded (FFPE) tissue blocks from histologically confirmed cases of anal carcinoma were included. DNA was extracted, and high-risk HPV genotyping was performed using the Anyplex™ II HPV28 PCR assay. Data were analysed using Stata version 15, and statistical significance was defined as a p-value < 0.05.

High-risk HPV DNA was detected in 35 of the 60 cases (58.3%). Among HPV-positive patients, 26 (74.3%) were female, and 09 (25.7%) were male. HPV16 was the most frequently identified genotype (50.0%), followed by HPV18 (19.6%) and HPV33 (8.7%). Multiple HPV genotypes were detected in 31.4% of positive samples. HPV-negative anal carcinoma was significantly associated with tumour involvement of both the anal canal and surgical margins, advanced T stages (stages III and IV), lymph node involvement, distant metastasis, and tumour size greater than 2 cm (all p < 0.001). Keratinising squamous cell carcinoma was the predominant histological subtype (51.7%), and half of the study participants (50.0%) were HIV-positive.

High-risk HPV infection, particularly with HPV16 and HPV18, is common among patients with anal carcinoma in Northwestern Tanzania and anal carcinoma with HPV negative status is associated with critical clinicopathological characteristics. Strengthening HPV vaccination, screening, and awareness initiatives could substantially reduce the burden of anal carcinoma in Tanzania.