Children whose tumors have lost a copy of 11q are older at diagnosis, and their tumors contain more segmental changes in gene copy number compared with children whose tumors show MYCN amplification.[61,62] Moreover, segmental chromosome changes not detected at diagnosis may be found in neuroblastomas at relapse. This suggests that clinically important tumor progression is associated with accumulation of segmental chromosomal alterations.
Current data do not support neuroblastoma screening. Screening infants for neuroblastoma by assay of urinary catecholamine metabolites was initiated in Japan. A large population-based North American study, in which most infants in Quebec were screened at the ages of 3 weeks and 6 months, has shown that screening detects many neuroblastomas with favorable characteristics [65,66] that would never have been detected clinically, apparently due to spontaneous regression of the tumors. Another study of infants screened at the age of 1 year shows similar results. Screening at the ages of 3 weeks, 6 months, or 1 year caused no reduction in the incidence of advanced-stage neuroblastoma with unfavorable biological characteristics in older children, nor did it reduce the number of deaths from neuroblastoma in infants screened at any age.[66,67] No public health benefits have been shown from screening infants for neuroblastoma at these ages. (Refer to the PDQ summary Neuroblastoma Screening for more information.)
Spontaneous regression of neuroblastoma
This phenomenon has been well described in infants, especially in those with the 4S pattern of metastatic spread. (Refer to the Stage Information section of this summary for more information.) In a German clinical trial, spontaneous regression and/or lack of progression occurred in nearly half of 93 asymptomatic infants aged 12 months or younger with stage 1, 2, or 3 tumors without MYCN amplification; all were observed after partial or no resection. Regression generally occurs only in tumors with a near triploid number of chromosomes, no MYCN amplification, and no loss of chromosome 1p. Additional features associated with spontaneous regression [70,71] include the lack of telomerase expression,[72,73] the expression of Ha-ras, and the expression of the neurotrophin receptor TrkA, a nerve growth factor receptor.