Preoperative staging, prognostic factors, and outcome for extremity rhabdomyosarcoma: A preliminary report from the Intergroup Rhabdomyosarcoma StudyIV (1991-1997)

Background: During the fourth Intergroup Rhabdomyosarcoma (RMS) Study (IRS IV, 1991-97), a preoperative staging system was evaluated prospectively for the first time. The authors evaluated this staging system and the role of surgery in extremity RMS in contemporary multimodal therapy. Methods: A total of 139 patients (71 girls; median age, 6 years) were enter ed in IRS IV with extremity-site RMS. Stage was assigned by the IRSG Preope rative Staging System. Postsurgical group was determined by tumor status af ter initial surgical intervention. Multivariate analysis was performed usin g all pretreatment factors that were significant by univariate analysis, in cluding clinical Group tie, I through IV), tumor invasiveness (T1,T2), noda l status (N0,N1), and tumor size (< or greater than or equal to 5 cm). Fail ure-Tree survival rates (FFS) and survival rates were estimated using the K aplan and Meier method. Results: Preoperative staging and clinical group distribution were as follo ws: Stage 2, n = 34; Stage 3, n = 73; Stage 4, n = 32; Group I, n = 31; Gro up II, n = 21;Group III, n = 54; Group IV, n = 33. Three-year FFS was 55%, and the overall survival rate was 70%. Eighty-seven patients had either unr esectable, gross residual disease (Group III) or metastases (Group IV). FFS was significantly worse for these patients with advanced disease, compared with that for patients with complete resection or with only microscopic re sidual tumor tie, Group I or Il; Group I, 3-year FFS, 91%; Group II, 72%; G roup III, 50%; Group IV, 23%; P < .001). Lymph nodes were evaluated surgica lly in 76 patients with positive results in 38. Clinically, 13 additional p atients had nodal disease. Both stage and group were highly predictive of o utcome and were highly correlated. By multivariate analysis, none of the ot her variables were predictors of FFS. Conclusions: This review confirms the utility of pretreatment staging for s tratification of patients with extremity RMS with widely different risks of relapse, thereby paving the way for development of risk-based therapy. Gro up (operative staging) remains the most important predictor of FFS, emphasi zing the importance of complete gross resection at initial surgical interve ntion, when feasible without loss of limb function. The high incidence of n odal disease in the patients who had lymph node biopsy confirms the need fo r surgical evaluation of lymph nodes to ensure accurate staging in children with extremity rhabdomyosarcoma. J Pediatr Surg 35:317-321. Copyright (C) 2000 by W.B. Saunders Company.