Study Identifies Total Body Irradiation Dose Levels Related to Cataracts and Renal Dysfunction

Severe cataracts seldom occur below 40 Gy in patients following myeloablative total body radiation therapy, according to a review of studies by Henk B. Kal and M. Loes van Kempen-Harteveld of the University Medical Center Utrecht.

The authors explored the radiation dose-response relationship between cataracts and renal dysfunction and the total body radiation therapy and hematopoietic stem cell transplants used to treat patients with hematological tumors. Biologically effective doses (BEDs) were calculated from the radiation doses associated with published incidences of cataract induction and late renal dysfunction.

A BED of 40 Gy for cataract formation was calculated from 17 studies, with a threshold BED of approximately 16 Gy for late renal toxicity determined from 14 studies.

“To prevent severe cataract, fractionated TBI should be applied to keep the BED less than 40 Gy,” concluded the authors. “Only when single-dose TBI cannot be avoided should eye shielding be applied. To prevent late renal toxicity, fractionated TBI is recommended, but kidney shielding remains necessary for almost all myeloablative TBI regimen.”

“Induction of Severe Cataract and Late Renal Dysfunction Following Total Body Irradiation: Dose-effect Relationships,” was published Aug. 8, 2009, in the Anticancer Research journal.