Long-term survival probabilities for childhood rhabdomyosarcoma. A population-based evaluation.

BACKGROUND: Evidence from clinical trials has documented improvements in event-free survival from childhood rhabdomyosarcoma (RMS) since the 1970s; however, the survival experience of children enrolled on cancer clinical trials may not reflect the full range of patients treated in community settings. The current study evaluated 5-year survival and 10-year conditional survival for RMS from U.S. population-based cancer registry data.

METHODS: Public-use data from the Surveillance, Epidemiology, and End Results (SEER) program were used in life table and Cox regression analyses to evaluate RMS survival by patient age at diagnosis, gender, tumor histology, tumor site and stage, and major treatment eras among 848 children who were age < 20 years at the time of diagnosis, were a resident of 1 of 9 geographic reporting regions, and were diagnosed between 1973 and 2000.

RESULTS: The 5-year survival probabilities were found to be highest for younger-age children (ages 1-4 years: 77%), patients with localized disease (83%), those whose tumors had an embryonal histology (67%), and patients with orbital (86%) and genitourinary (80%) tumor sites. Poor prognosis was associated with diagnosis during infancy (47%) and adolescence (48%); metastatic disease at the time of presentation (31%); alveolar histology (49%); and tumors of the extremities (50%), retroperitoneum (52%), and trunk (52%). Conditional 10-year survival probabilities among those who survived > or = 5 years were 85% or higher. The probability of survival by stage at the time of diagnosis increased with each successive treatment era, suggesting a stage shift phenomenon over time.

CONCLUSIONS: Large variations in 5-year survival were evident depending on patient age and tumor characteristics. However, children who survived the first 5 years after diagnosis were found to have an excellent long-term prognosis. The patterns in RMS survival noted from the current population-based evaluation did not appear to differ substantially from those previously reported by major clinical trials.