BACKGROUND: Inguinal lymph node metastasis is predictive of locoregional recurrence and poor overall survival in anal carcinoma. Metachronous lymph node metastasis occurs in 10% of all anal cancer patients, but multiple studies have shown that the benefit of elective irradiation of the groin depends on T-stage, and the toxicity of groin irradiation must not be underestimated.
OBJECTIVE: To analyze the inguinal recurrence rates among patients with anal carcinoma (T1-4, N0-1) who did not receive elective irradiation therapy to the groin and to determine predictors of inguinal recurrence.
DESIGN: Data on 119 patients treated between 1987 and 2005 were retrospectively analyzed. Patients were treated with 3-dimensional radiotherapy. The median dose was 60 Gy. During radiotherapy, 108 patients also received chemotherapy (5-fluorouracil and mitomycin-C).
RESULTS: AJCC staging showed a distribution of 21 T1 (18%), 58 T2 (49%), 27 T3 (23%), 13 T4 (11%), 101 N0 (85%) and 18 N1 (15%) tumors. The median follow up was 65 months (range, 1–240 months). The 5-year inguinal recurrence rate was 0% for T1, 10% for T2, 21% for T3 and 19% for T4 tumors (p = 0.034). T2 tumors of the perianal skin and the anal canal had 5-year inguinal recurrence rates of 12% and 8%, respectively. The 5-year inguinal recurrence rate was 21% for tumors ≥4 cm vs. 2% for tumors <4 cm in size (p = 0.003).
LIMITATIONS: Eleven patients did not receive chemotherapy.
CONCLUSIONS: Elective irradiation of the groin should be considered for local control in patients (N0-N1) with T2 tumors ≥4 cm in size and/or located in the perianal skin, and in all patients with T3 and T4 tumors.