Prognostic value of human papillomavirus in anal squamous cell carcinoma.

Purpose: Anal cancer is an uncommon malignancy, but its incidence is increasing worldwide. Chemoradiation is the standard primary treatment for patients with loco-regional limited disease. However, once patients develop metastatic spread, the prognosis is very poor. Human papillomavirus (HPV) is present in around 80 % of anal cancers, but its prognostic and/or predictive value is essentially unknown in this disease.

Methods: We retrospectively evaluated 50 patients with the diagnosis of anal squamous cell carcinoma treated at our institution with combined chemoradiotherapy for loco-regional limited disease. HPV status was evaluated from paraffin-embedded tumor tissues collected at the time of diagnosis by a polymerase chain reaction analysis.

Results: Among 50 patients, 42 (84 %) were HPV-positive. Thirty-two (64 %) patients were positive to genotype 16, two (4 %) to genotype 18, and three (6 %) to both 16 and 18. Lymph nodal involvement and clinical stage at diagnosis were more advanced for HPV-positive patients. After a median follow-up of 4 years (range 0.4-13.8), 46 (92 %) patients were alive. Overall, eight patients relapsed: One regional, one loco-regional, and six distant recurrences were observed. Four patients died of metastatic disease. Five-year disease-free survival (DFS) in HPV-positive and HPV-negative patients was 92.5 and 50.0 %, respectively (P < 0.01). In multivariate analysis, HPV-positivity was associated with a statistically significant better 5-year DFS (HR HPV+ vs HPV- 0.10; 95 % CI 0.02-0.50). Five-year overall survival in HPV-positive and HPV-negative patients was 93.3 and 66.7 %, respectively (P = 0.12).

Conclusions: In our study, HPV-positive anal cancers had a statistically significant improved DFS compared to HPV-negative group.