Long-term adverse effects on dentition in children with poor-risk neuroblastoma treated with high-dose chemotherapy and autologous stem cell transplantation with or without total body irradiation.

Chemo- and radiotherapy may have injurious effects on developing teeth. In this long-term follow-up study among poor-risk neuroblastoma (NBL) survivors our aims were: (1) to assess both the type and extent of the side-effects of the anticancer treatment on tooth development; and (2) to develop an index for expressing total damage to the permanent dentition. We studied the dental development from panoramic radiographs (PRG) of 18 long-term survivors treated under the age of 6 years with high-dose (HD) chemotherapy and autologous stem cell transplantation (ASCT) for poor-risk NBL. The myeloablative therapy was either HD chemotherapy and fractionated total body irradiation (TBI) of 10-12 Gy (TBI group, n = 10) or HD chemotherapy only (non-TBI group, n = 8). A defect index (DeI) was developed to describe the damage to the permanent dentition. The DeI was also tested in 18 healthy adolescents. All NBL patients had disturbances in dental development including short roots, arrested root development, microdontia and tooth aplasia. After TBI, 9/10 patients had very severe root defects, in contrast to none in the non-TBI group. All children in the TBI group had 2-12 (mean 6.6) missing permanent teeth, while 2/5 in the non-TBI group (3/8 excluded due to young age) had two and four missing permanent teeth, respectively. Microdontia was found at equal frequency in both groups. The mean value of the DeI was 70.0 (range 28-117) in the TBI group, 15.2 (range 4-34) in the non-TBI group (P<0.001, Mann-Whitney U test) and 1.8 (range 0-15) in healthy adolescents. Disturbances in dental development may compromise occlusal function in poor-risk NBL patients after ASCT, especially when TBI is included in the conditioning regimen. Long-term dental follow-up and rehabilitation is required.