Mitomycin and 5-fluorouracil for second-line treatment of metastatic squamous cell carcinomas of the anal canal.

Background: Metastatic squamous cell carcinomas (SCC) of the anal canal are rare and there is no international consensus on their second-line management. 5-Fluorouracil (5-FU) and mitomycin in combination with radiotherapy is the standard for locally advanced forms but its efficacy in metastatic stage has never been evaluated.

Patients And Methods: We report a retrospective analysis of patients treated with 5-FU and mitomycin from 2000 to 2017 in our institution for a metastatic SCC of the anal canal after failure of platinum-based regimen. The main outcome was progression-free survival (PFS) and the secondary outcomes were overall survival (OS), response rate, and toxicity.

Results: Nineteen patients, 15 women and four men, with a median age of 57 years were identified (range, 40-79 years). Patients received a median of three cycles (1-7) of mitomycin 5-FU. A dose reduction was necessary in six patients (31.6%), one patient had to discontinue treatment following toxicity and no death was due to treatment toxicity was reported. An objective response was observed in five patients (26.4%, 95% CI 6.6-46.2) including one complete response, six patients (31.6%, 95% CI 10.7-52.5) showed tumor stabilization. Median PFS and OS were 3 months [95% CI 1-5] and 7 months [95% CI 2.2-11.8]. Responder had a median duration of response of 4 months [95% CI 1.8-6.1] and one patient had 23 months duration of response. No significant difference was noted for PFS and OS for patients previously treated with mitomycin and 5-FU at a local stage.

Conclusion: Mitomycin and 5-FU regimen provides tumor control with acceptable tolerance. It is an option for patients with metastatic SCC of the anal canal after failure of platinum-based chemotherapy. [Correction added on 9 October 2019, after first online publication: '5-FU' was inadvertently removed from the Results and Conclusion and has now been added to the text.].