Disseminated neuroblastoma in children older than one year at diagnosis: comparable results with three consecutive high-dose protocols adopted by the Italian Co-Operative Group for Neuroblastoma.

Purpose: To compare the outcomes associated with modifications in three consecutive protocols employed by the Italian Co-Operative Group for Neuroblastoma (ICGNB) in disseminated neuroblastoma.
Patients and Methods: Between January 1985 and November 1997, a total of 359 children aged 1 to 15 years with newly diagnosed stage 4 neuroblastoma were enrolled in three consecutive protocols. Compared with ICGNB-85, the ICGNB-89 protocol contained two more chemotherapy cycles, and some drugs were given at greater doses, whereas in the ICGNB-92 protocol, the induction phase included a chelating agent, and individual cycles contained four drugs instead of two.
Results: A total of 330 of 359 evaluable children were included in this analysis; 106 children were treated with ICGNB-85, 65 children were treated with ICGNB-89, and 159 children were treated with ICGNB-92 protocols. Radical resection of primary tumor was carried out in 59.4%, 50.8%, and 57.9% of the patients, respectively. Major tumor response after induction therapy was achieved in 66.7%, 69.2%, and 68.6% of the patients, respectively. A total of 218 of 232 patients received consolidation therapy consisting of conventional chemotherapy in 65 patients and of high-dose chemotherapy in 153 patients. Disease recurrence or progression occurred in 82.1%, 69.2%, and 74.8% of the patients, respectively. Therapy-related deaths occurred in 1.9%, 12.3%, and 6.9% of the patients, respectively. Five-year overall survival (OS) for the three studies was 26%, 23%, and 28%, and event-free survival (EFS) was 19%, 17%, and 17%, respectively.
Conclusion: The therapeutic modifications adopted in the ICGNB-89 and ICGNB-92 protocols were not associated with a significant improvement in response rate or in the 5-year OS and EFS as compared with the ICGNB-85 protocol. Attempts at intensifying chemotherapy were associated with greater toxicity.