Rhabdomyosarcoma in adolescents: a report from the AIEOP Soft Tissue Sarcoma Committee.

Background: In many types of cancer, the survival rates are reported to be less favorable for adolescents compared with younger children. To investigate whether this is true for adolescents with rhabdomyosarcoma (RMS), the results obtained in patients enrolled in protocols run by the Italian Soft Tissue Sarcoma Committee (STSC) were analyzed.

Methods: From 1988 through 2005, 643 patients were registered (567 children ages birth-14 years and 76 adolescents ages 15-19 years) and treated in 4 STSC protocols. The number of patients enrolled was compared with the expected number calculated from incidence rates derived from the Italian network of cancer registries.

Results: Only 27% of the expected number of adolescents with RMS were enrolled in the STSC trials. Compared with children, adolescents were found to have a longer interval from initial symptoms to diagnosis (8 weeks vs 4.6 weeks), more alveolar RMS (47.4% vs 32.6%), lymph node infiltration (39.1% vs 23.3%), and metastases at the time of diagnosis (30.7% vs 17.8%). The 2 age groups received similar treatments. The 5-year overall survival (OS) rate was 68.9% in children versus 57.2% in adolescents (P = .006), and the progression-free survival (PFS) rate was 64.3% in children versus 48.1% in adolescents (P = .0237). On multivariate analysis, age, tumor site, lymph node involvement, and metastases were found to be significant prognostic factors for OS and PFS.

Conclusions: Survival for adolescents with RMS enrolled in STSC protocols appears to be satisfactory. The higher prevalence of unfavorable tumor characteristics noted among adolescents seems to explain their worse outcome compared with children. However, the limited number of adolescents enrolled in STSC studies is worrisome, and cooperation with oncologists who treat adults needs to be improved.