LATE RENAL-FUNCTION FOLLOWING WHOLE ABDOMINAL IRRADIATION

Sixty patients treated with whole abdominal radiotherapy who had remai ned disease-free since completion of treatment participated in a study to assess the late clinical and biochemical effects of bilateral rena l irradiation. Minimum follow-up was 5 years with a maximum of 20 year s and a median of 9 years. Fifty-two patients in the study group were treated for primary ovarian cancer. Seven had non-Hodgkins lymphoma ar ising in the gastrointestinal tract and one patient had a carcinoid tu mour arising in small bowel. None of the patients received chemotherap y. Abdominal radiation was given using an open beam technique to a mea n dose of 22.92 Gy (range 6.68-27.54 Gy) in 1.02 to 1.25 Gy fractions treated once daily. Posterior kidney shields were used in order to lim it the renal dose to < 20 Gy. Mean radiation dose to both kidneys (ret rospectively calculated) was 19.28 Gy (range 6.68-22.99 Gy). Patients ranged in age from 32-81 years with a median of 61 years. No patient h ad clinical evidence of renal impairment. Nine patients were hypertens ive prior to radiotherapy and a further five patients became hypertens ive after treatment. Serum creatinine values ranged from 44-123 mu mol /l, with a mean of 87 mu mol/l. Creatinine clearance ranged from 0.61- 2.38 ml/s (mean 1.28 ml/s). Tubular function tests revealed one border line high 24-h protein excretion and normal 24-h phosphorous and uric acid. Using a multiple linear regression analysis with creatinine clea rance as the endpoint, age was the only significant variable (P < 0.00 001) and renal dose and interval from treatment were not independently significant. There was no evidence of late renal toxicity more than 5 years after whole abdominal radiotherapy delivered with this techniqu e and dose/fractionation schedule, and using the clinical and biochemi cal endpoints assessed in this study.