Efficacy and prognostic analysis of 125I brathytherapy combined with chemotherapy for pediatric parameningeal rhabdomyosarcoma

Abstract

Objective: To analyze the efficacy and prognostic factors in children with parameningeal rhabdomyosarcoma (PMRMS) treated by 125I brachytherapy combined with chemotherapy. Methods: A retrospective analysis of the clinical data of 33 pediatric patients treated with 125I brachytherapy combined with chemotherapy in Peking University Stomatological Hospital from July 2013 to October 2018 was carried out to analyze the efficacy and prognostic factors. Results: Among the 33 patients, 19 were males and 14 were females; the median age was 4 years old (1-12 years old). There were 17 cases with embryonic type, 9 cases with alveolar type, and 7 with undifferentiated type; 26 cases with original PMRMS, and 7 cases with recurrent PMRMS. The tumors occurred in subtemporal-mastoid area in 15 patients, while nasopalatine-paranasal area in 6 cases, and parapharyngeal-submandibular area in 12 cases. There were 28 patients in IRS Ⅲ, and 5 patients in IRS Ⅳ. As for the risk level, 28 cases were in the middle-risk group and 5 cases in the high-risk group. The median follow-up time was 52 months. The 1, 3, and 5-year local control rates were 87.9%, 58.6%, and 49.9%, and the 1, 3, and 5-year survival rates were 93.8%, 60.5%, and 47.5%, respectively. The 5-year local control rate and 5-year survival rate of 12 patients with the tumor in the parapharyngeal-submandibular area were 91.7% and 100%, respectively. The 5-year local control rate and 5-year survival rate of the 6 patients with tumor in the nasopalatine-paranasal area were both 83.3%. The 3-year local control rate and 3-year survival rate of the 15 patients with tumor in the subtemporal-mastoid area were 17.5% and 21.4%. The multivariate survival analysis using Cox proportional risk regression model showed that the tumor located in the subtemporal-mastoid area was an independent risk factor affecting the 5-year overall survival rate (HR=38.40, 95%CI: 4.87-302.52, P=0.001). Within 3 months after 125I seed implantation, the incidence of acute radiotherapy adverse reactions in all patients was 84.8% (28/33). Twenty-one patients (63.6%) had a grade 1 acute radiotherapy reaction, and 7 cases (21.2%) had a grade 2 acute radiotherapy reaction. No acute radiotherapy adverse reactions of grade 3 or 4 occurred. Three months after 125I seed implantation, the adverse reactions were significantly alleviated, and no adverse reactions of grade 3 or above such as skin ulcer or salivary gland fibrosis occurred, and no serious cranio-maxillofacial deformities occurred. Conclusions: 125I seed brachytherapy combined with chemotherapy has a definite clinical effect in the treatment of children with parameningeal rhabdomyosarcoma. The prognosis of rhabdomyosarcoma in the parapharyngeal-submandibular area and nasopalatine-paranasal area is better than that in the subtemporal-mastoid area.