Table 7. Children's Oncology Group (COG) Neuroblastoma Intermediate-Risk Group Assignment Schema Used for COG-P9641 and COG-A3961 Studiesa continued...
Whether initial chemotherapy is indicated for all intermediate-risk infants with localized neuroblastoma is controversial.
Evidence (surgery and chemotherapy):
In North America, the COG (COG-A3961) investigated a risk-based neuroblastoma treatment plan that assigned all patients to a low-, intermediate-, or high-risk group based on age, International Neuroblastoma Staging System (INSS) stage, and tumor biology (i.e., MYCN gene amplification, International Neuroblastoma Pathology Classification system, and DNA ploidy). This study investigated an overall reduction in treatment compared with prior treatment plans in patients with unresectable, localized, MYCN-nonamplified tumors. The intermediate-risk group received four to eight cycles of moderate-dose neoadjuvant chemotherapy (carboplatin, cyclophosphamide, doxorubicin, and etoposide), additional surgery in some instances, and avoided radiation therapy. Of the 464 intermediate-risk tumors (stages 3, 4, and 4S), 69.6% of them had favorable features, defined as hyperdiploidy and favorable histology, and were assigned to receive four cycles of chemotherapy.
The administration of neoadjuvant chemotherapy facilitated at least a partial resection of 99.6% of the previously unresectable tumors. No significant difference was noted in overall survival (OS) according to the degree of resection (complete vs. incomplete, P = .37).
Only 2.5% of the 479 patients received local radiation therapy. The 3-year event-free survival (EFS) was 88% and OS was 95%.
The 3-year EFS was 92% for patients with stage 3 disease (n = 269), 90% for patients with stage 4S disease (n = 31), and 81% for patients with stage 4 disease (n = 176) (P < .001 for stages 3 and 4S vs. stage 4); the 3-year OS estimates were 98% for stage 3 disease, 97% for stage 4S disease, and 93% for stage 4 disease (P = .002 for stages 3 and 4S vs. stage 4).
There was no difference in OS in patients with favorable biologic features between those who received eight cycles of chemotherapy (100%) compared with those who received four cycles (96%).
There was no unexpected toxicity.
A German prospective clinical trial enrolled 340 infants aged 1 year or younger whose tumors were stage 1, 2, or 3, histologically verified, and lacked MYCN amplification. Chemotherapy was given at diagnosis to 57 infants with organs threatened by tumor. The tumor was completely resected or nearly so in 190 infants who underwent low-risk surgery. A total of 93 infants whose tumors were not resectable without high-risk surgery, due to age or organ involvement, were observed without chemotherapy.
Further surgery was avoided in 33 infants and chemotherapy was avoided in 72 infants.
The 3-year OS rate for the infants who were observed without treatment was 99%. The metastases-free survival rate was 94% for infants with unresected tumors and was not different from infants treated with surgery or chemotherapy (median follow-up, 58 months).
Forty-four of 93 infants with unresected tumors experienced spontaneous regression (17 were complete regressions) and 39 infants experienced progression.
The investigators suggested that a wait-and-see strategy is appropriate for infants with localized neuroblastoma because regressions have been observed after the first year of life.
Moderate-dose chemotherapy has been shown to be effective in the prospective Infant Neuroblastoma European Study (EURO-INF-NB-STUDY-1999-99.1); about one-half of the infants with unresectable, nonmetastatic neuroblastoma and no MYCN amplification underwent a safe surgical resection and avoided long-term adverse effects.[Level of evidence: 3iiA]
The 5-year OS rate was 99% and the EFS rate was 90% (median follow-up, 6 years).
In this study, infants undergoing surgical resection had a better EFS than those who did not have surgery.
In two European prospective trials of infants with disseminated neuroblastoma without MYCN gene amplification, infants with INSS stage 3 primary or positive skeletal scintigraphy were not started on chemotherapy unless life-threatening or organ-threatening symptoms developed. Chemotherapy when given consisted of short-dose and standard-dose chemotherapy.
The OS was 100% in the 41 patients who did not have INSS stage 4S regardless of initial chemotherapy.
In infants with overt metastases to the skeleton, lung, and central nervous system, the 2-year OS was 96% (n = 45).
No patients died of surgery-related or chemotherapy-related complications on either protocol.