This study examined long-term side effects of radiation therapy on sexual function. Researchers report a range symptoms related to sexual function among long-term prostate cancer survivors.

Radiation therapy is a common treatment for localized prostate cancer. It involves directing high-energy rays at the tumor site to target and kill cancer cells. There are different forms of radiation therapy. Some are administered from outside the body (external beam radiation therapy or EBRT), and some from within the body (brachytherapy). Both types of radiation therapy can be combined for a more intensive intervention. A commonly reported side effect of radiation therapy is erectile dysfunction. The long-term effects on other sexual functions (such as sexual motivation and orgasm) are less well understood. 

This study aimed to assess a range of sexual functions in long-term prostate cancer survivors treated with radiation therapy.

518 prostate cancer survivors were included in this study. All men were successfully treated with EBRT alone or in combination with brachytherapy, either as primary or salvage therapy. A further 155 healthy men who had never received radiation to the pelvic area were included as a control group. All men were non-diabetic, sexually active and completed a questionnaire assessing sexual and erectile function. The average time since treatment at follow-up was 5 years.

Men previously treated with radiation therapy were significantly more likely to report symptoms related to sexual function than men in the control group. This remained significant regardless of factors such as age, sexual function before treatment, previous hormone therapy, and smoking. Overall, men treated with previous radiation therapy had 1.5 to 1.9 times less sexual intercourse than men in the control group.

Among prostate cancer survivors, 37% reported having no semen following ejaculation. This is compared to 1% in the control group. Ejaculations were also rated as more painful in men with previous radiation therapy. Prostate cancer survivors were 4 times less likely to achieve an erection sufficient for intercourse. This was significant regardless of the type of radiation therapy received. Men treated with salvage EBRT (therapy following cancer recurrrence) were 6.6 times less likely to achieve an erection without aids compared to the control group.  

Being older and having undergone radiation therapy more than 5 years ago increased the likelihood of erectile dysfunction. Time since treatment (more than 5 years) also significantly increased orgasm-related symptoms in men treated with salvage EBRT, and ejaculatory dysfunction in men treated with EBRT and brachytherapy.

Researchers concluded that symptoms related to erectile, sexual, and ejaculatory function are common among men previously treated with radiation therapy.

Discuss any concerns or symptoms of sexual dysfunction with your doctor.