Prognosis of children with soft tissue sarcoma who relapse after achieving a complete response. A report from the Intergroup Rhabdomyosarcoma Study I.

Four hundred and twenty-three children with newly-diagnosed soft-tissue sarcoma were treated on the Intergroup Rhabdomyosarcoma Study I from November 1972 through December 1976. After institution of therapy, 341/423 (80.6%) achieved a complete response (no detectable tumor), but 115/341 (33.7%) subsequently relapsed. The types and efficacy of management after relapse were ascertained by questionnaire. Information sufficient for critical analysis was obtained for 98/115 patients (85%). Thirteen of the 98 patients had an isolated local recurrence; the other 85 developed metastases in regional, distant, or multiple sites simultaneously. Patients with distant metastases at diagnosis were most likely to develop recurrence, as were those with sarcoma arising in the perineum-anus, retroperitoneum-pelvis, gastrointestinal tract, or extremity. Those with tumor primary in the orbit or genitourinary tract had the lowest recurrence rate, as did those whose tumor histology was nonalveolar. Individualized treatment was given to 90 of the 98 patients after relapse, and a second complete response was achieved in 33 of them (37%). However, only five of the 90 patients (5.5%) are currently tumor-free. The outlook is poor when recurrence develops in patients still receiving chemotherapy; only two of 74 such patients survive, compared to three of 16 who have relapsed after cessation of treatment. Relapse after initial complete response to therapy has a poor prognosis, regardless of site of recurrence. Although effective retrieval therapy can prolong survival, only 2 of 12 patients (17%) with local recurrence and three of 78 patients (4%) with metastatic recurrence remain free of disease.