Skeletal effects of orthovoltage and megavoltage therapy following treatment of nephroblastoma

Abstract

A review of 19 patients treated for nephroblastoma between 1945 and 1978 by nephrectomy and radiotherapy with chemotherapy showed a marked improvement in cure rate in recent years. In the decade from 1950 to 1960 there are four survivors. From 1960 to 1970, there are nine survivors from 25 cases and since 1970 there are 19 survivors from 27 cases. Skeletal effects of radiation therapy have been reviewed in 22 patients--seven of whom had orthovoltage and 15 megavoltage therapy. Similar skeletal changes followed both orthovoltage and megavoltage therapy, being more severe after the adolescent growth spurt and when the follow-up was longer. The radiation dose was normally 3000 cGy and skeletal changes followed the lowest dose of 2200 cGY. Scoliosis of the lumbar spine, concave to the side of the tumour, with angulation ranging from less than 5 degrees to 54 degrees developed in 12 patients; all but one showed asymmetry of the body LV2. Kyphosis was present in three patients; anterior beaking of the vertebral body in 10; and 16 patients showed asymmetry of more than one vertebral body. Iliac hypoplasia was present in 19 patients, being unilateral when only the renal bed was irradiated. Analysis of the radiological changes expressed as a total score against the age at follow-up shows that severe changes follow orthovoltage therapy. It is too early to assess the full extent of megavoltage therapy simply because patients have not been followed up for a comparable length of time.