Value of postchemotherapy bioptical verification of complete clinical remission in previously incompletely resected (stage I and II pT3) malignant mesenchymal tumors in children: International Society of Pediatric Oncology 1984 Malignant Mesenchymal Tumors Study.

Bioptical verification of complete clinical remission achieved with postoperative chemotherapy in 140 pediatric patients with nonradically resected stages I and II nonparameningeal malignant mesenchymal tumors was evaluated. Tumor histology was rhabdomyosarcoma in 92 and nonrhabdomyosarcoma in 48 patients. All were included in the International Society of Pediatric Oncology "1984 Malignant Mesenchymal Tumors Study." Treatment given after nonradical surgery and before the biopsy consisted of 3 to 6 IVA courses (ifosfamide, vincristine, actinomycin D). Complete clinical remission (no tumor at physical examination, X-rays, sonography, computed tomography, scintigraphy) was bioptically confirmed in 52 rhabdomyosarcoma and 23 nonrhabdomyosarcoma cases, whereas in all the remaining patients (39 rhabdomyosarcoma and 22 nonrhabdomyosarcoma) complete clinical remission was not bioptically verified. Forty-eight-month local relapse rates were 51% in bioptically confirmed and 48% in nonbiopsied rhabdomyosarcoma patients. In nonrhabdomyosarcoma cases, relapse rates were 25% and 14%, respectively. In 4 cases, bioptical specimens contained tumor cells. In spite of aggressive treatment, only 1 is actually in remission. The total 48-month relapse rate (biopsied and nonbiopsied) was significantly higher in rhabdomyosarcoma patients (50%) than in nonrhabdomyosarcoma patients (26%). The value of bioptical verification of complete clinical remission seems to be limited in our series, when known that relapse rate in bioptically confirmed complete remission cases remained high and the outcome in rare "positive biopsy patients" was poor.