Prognostic factors and their influence on therapeutic outcomes in children and adolescents with parameningeal rhabdomyosarcoma: A multicenter study from Pakistan

Background: The study was aimed at evaluating prognostic factors and treatment outcomes of pediatric parameningeal rhabdomyosarcoma (PM-RMS) at two major pediatric oncology centers in Pakistan. Methods: PM-RMS age 1–16 years diagnosed from 2005 to 2015 at Aga Khan University Hospital and The Indus Hospital were identified. Factors relevant to survival and relapse were analyzed. Results: Forty-Six patients were identified. Thirty-three (72%) patients were analyzed. Seventeen (52%) patients were stage III (group-III), 15 (46%) were stage II (group-III) and 1 (3%) was stage IV (group-IV). Twenty-nine (88%) were embryonal. Majority (n = 25, 76%) received vincristine, actinomycin and cyclophosphamide while three (9%) received high-risk protocol. Twenty-three (69.6%) received radiation whereas two (6%) patients each were treated with surgery and surgery + radiation. Improved 3-year overall survival (OS) (77%, P = 0.04) was associated with a dose of 50Gy radiation and (77%, P = 0.02) with baseline nutritional status Z-scores ≥ - 2SD. Age ≥10 years (33%, P = 0.80), stage III disease (33%, P = 0.08) and regional nodal involvement (25%, P = 0.12) showed inferior 3-year event free survival (EFS). Three-year overall survival (OS) was 37% (95% CI: 16%-58%), 3-year (OS) excluding treatment abandonment was 47% (95% CI: 21%-70%) and 3-year event free survival with relapse, deaths and treatment abandonment was 23% (95% CI: 9%-41%) respectively. Conclusion: Our study demonstrates improved survival with adequate dose of radiation and nutritional status (Z-scores) ≥ - 2SD. Less advanced disease and lack of nodal involvement correlates well with outcomes. Treatment abandonment remains problematic in developing countries. Retrospective analysis restricted meaningful outcomes, suggesting future collaborative studies.