assessment of variations in serum testosterone, follicle stimulating hormone, and luteinizing hormone levels in patients receiving radiotherapy for rectal cancer

Background: testes being in close proximity to radiation fields in patients of rectal cancer treated with radiotherapy, inadvertently receive a part of the radiation dose. this study was conducted to evaluate the variation of male sex hormones during the course of radiotherapy in patients with rectal cancer.method: in this single-institution prospective study, 20 patients with carcinoma rectum were included. the patients were treated with 3-dimensional conformal radiation therapy or intensity modulated radiation therapy technique to a dose of 50.4 gy for five weeks. serum testosterone, follicle stimulating hormone (fsh), and luteinizing hormone (lh) levels were obtained prior to and in the meantime of radiotherapy. the post treatment hormone levels were compared to the baseline values. the mean, percentage, standard deviation, and paired t-test were used for statistical analysis.results: the mean dose received by the testes was 2.65 gy (1.96 gy to 4.96 gy), which accounted for 5.25% of the total dose. the baseline values of serum testosterone, fsh, and lh were 4.65 ± 0.7 ng/ml, 7.57 ± 1.2 miu/ml, and 7.93 ± 1.1 miu/ml, respectively. there was a 32.1% drop in the post treatment testosterone levels compared with the baseline. there was a 77% rise in the post treatment fsh and 40.2% rise in the post treatment lh levels compared with the baseline. there was a significant difference in the rise of lh levels in the patients who received a testicular dose more than 2gy compared with those who received a dose less than 2 gy.conclusion: radiation therapy was found to have a significant acute impact on male sex hormones in patients receiving radiotherapy for rectal cancer.