Para-aortic radiation ups risk of diabetes in testicular cancer survivors
Para-aortic irradiation appears to increase the risk of diabetes among testicular cancer (TC) survivors compared to surgery only, suggests a recent study.
There were 161 TC survivors diagnosed with diabetes during a median follow-up of 13.4 years. Risk of diabetes was not higher compared to general population rates (standardized incidence ratios [SIR], 0.9; 95 percent CI, 0.7–1.1).
Para-aortic radiotherapy correlated with a 1.66-fold (1.05–2.62) increased risk of diabetes compared to no radiotherapy after adjustment for age. For every 10-Gy increase in the prescribed radiation dose, the excess hazard increased by 0.31 (0.11–0.51; p=0.003), adjusted for age and body mass index. In irradiated patients, the excess hazard increased by 0.33 (–0.14 to 0.81; p=0.169) with every 10-Gy increase in radiation dose.
Apart from diabetes risk, an earlier study also found a dose-response relationship between radiotherapy and pancreatic cancer risk among TC survivors. Researchers noted that such excesses, although small, must be taken into account when radiotherapy with exposure to the pancreas is considered for newly diagnosed patients. [Br J Cancer 2016;115:901-908]
In the present study, the investigators analysed the risk of diabetes in 2,998 1-year TC survivors treated before 50 years of age with orchidectomy with/without radiotherapy between 1976 and 2007. They also compared the incidence of diabetes with general population rates. A case-cohort design was used to assess treatment-specific diabetes risk.
TC is considered the most curable solid tumour, with a 10-year survival rate of more than 95 percent, according to a study by Travis and colleagues. [J Natl Cancer Inst 2010;102:1114-1130]