Inguinal SLN biopsy in patients with anal cancer should be considered the procedure of choice for staging inguinal lymph nodes. It is easy to perform, has no serious morbidity, and can help detect occult inguinal metastatic disease. Currently, there is no standard management for the treatment of the inguinal areas in N- patients and routine elective irradiation of the bilateral inguinal areas may not be advisable. Inguinal SLN biopsy could help identify patients with negative SLN who should be spared prophylactic radiotherapy and its associated morbidity and those who could benefit from inguinal irradiation. Further larger scale multicenter studies with long-term follow-up data are needed to validate these results.