Comprehensive treatment experience of anal squamous cell carcinoma from a tertiary cancer center in South China.

Background Anal squamous cell carcinoma (ASCC) is a rare malignant tumor with increasing incidence. The goal of our study was to analyze the treatment outcome and prognostic factors of ASCC in South China in the past half-century. Methods This study retrospectively included 59 patients with ASCC admitted from 1975 to 2018 in Sun Yat-sen University cancer center. The clinical records and follow-up information of all patients were collected. Survival analysis and univariate and multivariate regression analyses were performed using the "survival" and "survminer" packages of R software. Results In 59 patients, 5 patients had distant metastasis at diagnosis. Among 54 M0 stage patients, 33 patients received chemoradiotherapy (CRT), 19 patients received local surgery, and 2 patients refused curative treatment and received the best supportive treatment (BST). The most common grade 3-4 acute toxicities during treatment were myelosuppression and radiation dermatitis. The median follow-up time was 32 months. For the whole group, the 3-year and 5-year overall survival (OS) rates and disease-free survival (DFS) were 71.1% and 63.6%, and 73.4% and 69.0%, respectively. Multivariate regression analysis showed that the T3-4 stage was an independent prognostic risk factor for OS, progression-free survival (PFS), and DFS. And M1 was an independent prognostic risk factor for PFS and DFS. Patients in stage M0 mainly treated with CRT had better local control than those mainly treated with surgery (p = 0.027). For M0 patients, induction chemotherapy combined with CRT tends to prolong OS compared with CRT alone (p = 0.26). The 3-year colostomy-free survival for the whole group was 81.1%. Conclusions CRT is recommended as the first choice for the treatment of M0 stage ASCC. Induction chemotherapy may bring better survival benefits for some patients. Patients with ASCC in China seem to have a better local control rate, which suggested different treatment strategies may be needed in China.