Prognostic factors of squamous cell carcinoma of the anal margin treated by radiotherapy: the Lyon experience

To report our patient experience with squamous cell carcinoma of the anal margin and to evaluate the prognostic factors influencing outcome.

Between 1980 and 2001, 26 patients with anal margin squamous cell carcinoma were treated in Lyon-Sud: 7 T1, 14 T2, 4 T3, and 1 T4 with 20 N0, 3 N1, and 3 N2. The anal canal was invaded in five patients. Treatment consisted of definitive external irradiation in 14 patients and adjuvant irradiation (after a local excision) in 12 patients. External irradiation was combined with chemotherapy in seven patients, brachytherapy in four patients, and both brachytherapy and chemotherapy in one patient.

The local control rate was initially 61.4%, and it was 80.8% after salvage treatment. The 5-year overall and specific survival rates were 71 and 88.3%, respectively. Three factors correlated with specific survival: cell differentiation (P=0.038) and T (P=0.001) and N category (P=0.0005). A salvage abdominoperineal resection was successfully employed in five of seven local recurrences. Four grade 3 and two grade 4 toxicities were observed. Sphincter preservation was possible in 66% of alive patients.

Our results confirm the dominating place of definitive irradiation and radiochemotherapy in the treatment of anal margin squamous cell carcinoma. The indications for abdominoperineal resection must be limited to local relapse. The prognosis of squamous cell carcinoma is correlated to T and N staging and cell differentiation.