Background: Standard treatment of localized squamous cell carcinoma of the anus (SCCA) is radiotherapy (RT) combined with chemotherapy, that is, chemoradiation (CRT). Primary surgery has a limited role, but is a recommended treatment for small well differentiated SCCA localized in the anal margin, with re-excision or postoperative RT/CRT in case of involved surgical margins. The evidence supporting these strategies is limited.
Aim: To study the recurrence patterns and survival outcomes in patients treated with surgery alone compared with surgery followed by postoperative RT/CRT.
Material and methods: From a large Nordic database we identified 93 patients with stage TxT1-2N0M0 SCCA treated with surgery alone (n = 59) or surgery followed by RT/CRT (n = 34). Surgery consisted of local excision in 86 patients and abdominoperineal resection in seven patients, all of them in the surgery alone group. In 38 (41%) of the patients, the tumor was localized merely in the anal margin and in all remaining cases the anal canal was involved. Median RT dose to the tumor bed was 54 (range 46-66) Gy. Adjuvant RT to lymph nodes was given in 75% of the patients. Half of the patients received concomitant chemotherapy, usually 5-fluorouracil and mitomycin C.
Results: The locoregional recurrence (LRR) rate was significantly higher after surgery alone compared to surgery followed by adjuvant RT/CRT (36% vs. 9%, p = .006). The 3-year recurrence free survival (RFS) and overall survival (OS) were significantly better in patients who received postoperative RT/CRT than in patients who did not (3-year RFS 84.2% vs. 52.7%, p < .001 and 3-year OS 87.2% vs. 70%, p = .026).
Conclusions: Surgery alone of SCCA was associated with a high LRR rate and poor survival. The addition of postoperative RT/CRT lead to significantly improved locoregional control and survival.