Although > 90% of children with nonmetastatic rhabdomyosarcoma (RMS) achieve complete remission with current treatment, up to one-third of them experience a recurrence. Survival rates are not always poor in patients who develop recurrences; thus, prognostic factors are needed to tailor salvage treatment.

The current analysis included 125 children who were affected by localized RMS and were enrolled in 3 consecutive Italian protocols (RMS79, RMS88, and RMS96) who developed recurrences after complete remission. Patient, tumor, and treatment characteristics were studied in univariate and multivariate analyses to determine the independent significance of different factors.

The median time from diagnosis to recurrence was 17.8 months. Most patients had local recurrences (72%). The 5-year overall survival (OS) rate was 28.3% +/- 8.7%. Multivariate analysis identified 4 factors that were associated with poor survival: 1) alveolar subtype (relative risk [RR], 2.0), 2) parameningeal or "other" sites (RR, 2.6), 3) systemic recurrence (RR, 3.1), and 4) recurrence on therapy (RR, 2.3). The absence of any of these risk factors identified a "favorable risk" group (12% of patients) with a 5-year OS rate of 71.8% +/- 23.5%. Patients with a single risk factor (32%) had an OS rate of 37.5% +/- 17.2%. Combining patients with 0 or 1 risk factor, the OS rate was 66.5% in the subgroup who had not received radiotherapy compared with an OS rate of 30.3% in the subgroup who had received radiotherapy; this difference was significant (P = 0.03).

The results of the current analysis demonstrated that groups with a different prognosis can be identified among patients with recurrent RMS. Patients with a nonalveolar histology, a primary site other than the parameningeal or "other" sites, local recurrence, and recurrence off therapy had a better prognosis. First-line treatment may have an impact on prognostic variables. In fact, patients who had no or only one risk factor and patients who had tumors with a nonalveolar histology benefited more from salvage therapy if they had not received radiotherapy for their initial treatment. These data may be useful in planning risk-adapted salvage protocols.