Parameningeal Rhabdomyosarcoma-Clinical Profile, Outcomes, and Prognostic Factors in Children Treated at a Single Center Over a Decade.

BACKGROUND

Parameningeal rhabdomyosarcomas (PM-RMS) in children is challenging to treat. While a 10-year event-free survival (EFS) of 62% has been reported from high-middle income countries (HMICs) for localized disease, data is limited from low-middle income countries (LMICs). We studied the clinical profile, outcomes, and prognostic factors in PM-RMS.

MATERIALS AND METHODS

Children aged 15 years or younger with PM-RMS treated on a uniform chemotherapy protocol from January 2013 to December 2021 were retrospectively analyzed. Local therapy at 10 to 12 weeks of induction was radiotherapy (RT)+/-surgery, where possible, with early RT for intracranial extension (ICE).

RESULTS

Seventy-six patients with a median age of 6.7 years (range: 3.2 to 15 y), male to female ratio of 1.8:1 formed the study cohort. Eleven patients (14.5%) had metastasis (lungs: 8, bone: 2, and bone marrow: 1) and ICE was seen in 46.1% (n=35). Twenty-five patients (49.0%) had alveolar histology with PAX3/7 positive in 17/59 (28.8%). The median tumor size (t size ) at baseline was 5.2 cm (range: 1.2 to 12.8 cm). Seventy-one patients received RT and 5 also underwent surgery. At a median follow-up of 65 months (range: 53 to 76 mo) 4 year EFS, OS of the whole cohort were 47.3% (95% CI: 34.8%-58.8%), 51.7% (95% CI: 38.0%-64.0%), respectively. Four-year EFS, OS of the localized and metastatic cohort were 54.7% (95% CI: 41.3%-68.1%), 56.0% (95% CI: 42.0%-70.0%), and 9.1% (95% CI: 0%-26.5%), 18.2% (95% CI: 0%-47.8%), respectively. Metastases (HR: 3.38, 95% CI: 1.57-7.26, and P =0.002), t size (HR: 1.17, 95% CI: 1.02-1.34, and P =0.026) were prognostic for survival on multivariate analysis.

CONCLUSIONS

Survival of children with localized PM-RMS in our study is relatively fair compared with the reported literature probably due to the application of RT in all despite higher proportion of larger tumors, unfavorable sites of primary, and intracranial extension. Identification of high-risk subsets and optimizing current treatment strategies, both systemic and local therapy may partly improve outcomes.