Squamous cell carcinoma of the anal canal is a rare cancer with an increasing incidence. It represents 2.5% of digestive cancers and occurs more frequently in immunocompromised persons, in particular HIV positive. It is a cancer that develops essentially locally, with only 5% of metastases at diagnosis. The reference treatment for forms deemed localized after clinico-bio-radiological pre-therapeutic evaluation is radiochemotherapy allowing a 5-year survival rate of about 80%. However, up to 30% of patients fail radiochemotherapy. Failure is defined as persistent disease (non response or progression in 10 to 15% of patients) or relapse (local or metastatic in 10 to 15% of patients). Salvage surgery by abdominoperineal amputation is indicated in this case after elimination of the metastatic character with an overall survival rate at 5 years varying from 23 to 69%. This complex and cumbersome surgery is burdened with significant postoperative morbidity with alteration of the quality of life. Investigators would like to perform a retrospective and prospective study in the Paris Saint-Joseph hospital group to evaluate the interest of abdominoperineal amputation in case of failure of radiochemotherapy in patients with squamous cell carcinoma of the anal canal.

Inclusion Criteria:

• Patient with abdominoperineal amputation for squamous cell carcinoma of the anus
• Patient whose age ≥ 18 years
• French speaking patient

Exclusion Criteria:

• Patient under guardianship or curatorship
• Patient deprived of liberty
• Patient under court protection
• Patient objecting to the use of his data for this research

These patients were referred for squamous cell carcinoma of the anus for abdominoperineal amputation between 09/03/2010 and 05/01/2021.