Recurrent Neuroblastoma in Patients Initially Classified as Intermediate Risk

The COG ANBL0531 (NCT00499616) study treated patients with newly diagnosed intermediate-risk neuroblastoma with chemotherapy consisting of carboplatin, etoposide, cyclophosphamide, and doxorubicin. Retrieval therapy was included in the protocol for patients who developed progressive nonmetastatic disease within 3 years of study enrollment. Up to six cycles of cyclophosphamide and topotecan could be given to patients. Of 29 patients who received cyclophosphamide and topotecan, 18 remained event free, 9 experienced relapse, and 2 died. Twenty patients who experienced an inadequate initial response to eight cycles of chemotherapy were treated with cyclophosphamide and topotecan. Of those 20 patients, 9 patients achieved a very good partial response or better; however, 6 patients developed progressive disease or experienced relapse, and 1 patient died. This suggests that more aggressive therapy is needed for patients who do not achieve the defined treatment end point after eight cycles of chemotherapy.[19]

A COG study for intermediate-risk neuroblastoma (COG-A3961) enrolled 479 patients, 42 of whom developed disease progression. The recurrence rate was 10% for those with favorable biology and 17% for those with unfavorable biology. Thirty patients had locoregional recurrences, 11 had metastatic recurrences, and 1 had both types of recurrent disease. Six of the 42 patients died of disease, while 36 patients responded to therapy. Thus, most patients with intermediate-risk neuroblastoma and disease progression may be salvaged.[16] It is not feasible to compare these results with the results of the other COG intermediate-risk study (ANBL0531) because of differences between the classification of patients for eligibility in the two studies.[19]