Patterns of failure for rhabdomyosarcoma of the perineal and perianal region.
Academic Article
Overview
abstract
PURPOSE: To analyze prognostic factors and patterns of failure for rhabdomyosarcoma of the perineal and perianal region (PRMS), with an emphasis on radiation therapy for locoregional control. METHODS AND MATERIALS: Detailed records of all 14 patients treated for PRMS at Memorial Sloan-Kettering Cancer Center between 1998 and 2012 were reviewed. The Kaplan-Meier method was used to assess the event-free survival (EFS) and overall survival (OS), and a competing-risks analysis was used to assess the cumulative incidence of local, regional, and distant failures. RESULTS: Median age was 15.8 years (range, 1.1-31.9 years). High-risk features were identified: 9 of 14 patients (64%) had group 3 disease and 3 of 14 (21%) had group 4; 11 of 14 tumors (78%) were alveolar; 12 of 14 tumors (86%) were ≥5 cm; and 9 of 14 patients (64%) had involved lymph nodes (N1). Of those aged ≥10 years at diagnosis, 9 of 10 (90%) had alveolar histology, all had tumors ≥5 cm, and 8 of 10 (80%) presented with N1 disease. The rates of local, regional, and distant failure at 5 years were 17%, 31%, and 52%, respectively. Although 3 of the 4 patients with regional failure received nodal irradiation, only one of the nodal failures occurred in the radiation therapy field. The 5-year EFS was 33%, and OS was 39%. Age ≥10 years was associated with poor outcomes: EFS was 13% in patients aged ≥10 years, compared with 75% in those aged <10 years (P=.04); the OS was 13% in patients aged ≥10 years, compared with 100% in those aged <10 years (P=.04). CONCLUSIONS: Patients with PRMS, especially those aged ≥10 years, present with poor prognostic features and continue to have poor outcomes. Given the high incidence of regional node recurrence, we recommend prophylactic ilioinguinal lymph node irradiation for all patients aged ≥10 years. For children aged <10 years, nodal evaluation is essential to determine the role for lymph node irradiation.
