The addition of paclitaxel in chemoradiotherapy of anal squamous cell carcinoma: a prospective randomized phase 3 trial

Abstract

AIM: to compare long-term outcomes and safety of the addition of paclitaxel to chemoradiotherapy for squamous cell anal carcinoma.PATIENTS AND METHODS: A prospective phase 3 randomized trial included patients with histologically verified non-metastatic anal squamous cell carcinoma. Patients received radiotherapy 52-54 Gy (for T1-T2 tumors) and 56-58 Gy (for T3- T4 tumors) in 2 Gy daily fractions during chemotherapy with mitomycin C (10 mg/m2 i.v. day 1), capecitabine (625 mg/m2 2 times a day orally on days of radiation therapy), paclitaxel (45 mg/m2 i.v. on days 3, 10 , 17, 24, 31) during 2013-2019. In the control group patients received a similar course of RT and chemotherapy with mitomycin C (12 mg/m2 i.v. day 1 ), capecitabine (825 mg/m2 2 times a day orally on radiotherapy days). The primary endpoint was 3-year disease-free survival (DFS). Secondary endpoints included complication rate (NCI-CTCAE 4.0), complete clinical response rate at 12 weeks and 26 weeks after completion of CRT, and 3-year overall survival (OS).RESULTS: The study and control groups included 72 patients each. The median follow-up was 39.5 months. A complete clinical response at the 26-week follow-up was recorded in 64 (88.9%) patients in the study group and in 54 (75%) patients in the control group (p=0.049). There were no differences in the incidence of complications of grades 3-4 in the two groups (39/72 [54.2%] in the study group versus 35/72 [48.6%] in the control group (p=0.617)). Three-year progression-free survival in the study group was 87.1%, in the control group - 64.4% (p=0.001). Three-year overall survival in the study group was 95.5%, in the control group - 80.0% (p<0.001).CONCLUSION: CRT with paclitaxel for squamous cell anal carcinoma has acceptable toxicity and may improve long-term treatment outcomes.