Evaluating the effects of radiation doses on erectile function in localized prostate cancer treated with permanent prostate brachytherapy.

This study investigated the relationship between radiation doses in prostate brachytherapy (BT) and erectile function reduction in patients with localized prostate cancer (PCa). The data showed that sexual function decreased over time with higher doses of BT.

Localized prostate cancer (PCa) is a form of cancer that has not spread beyond the prostate gland. PCa can be treated by surgery, radiation, or hormone therapy. Men with PCa usually have high levels of prostate-specific antigen (PSA). PSA is a protein made by the cells of the prostate gland.

Prostate Brachytherapy (BT) is a type of radiation therapy that uses a radioactive implant device into the cancer tissue. It slowly releases radiation and kills cancer cells over time. It can be administered as a low-dose (several days or longer) or a high-dose (for a few minutes) treatments, depending on the length of time the radioactive implant remains in the cancer tissue.

BT has been shown to improve the overall survival of patients with localized PCa. However, a significant number of patients develop erectile dysfunction (ED) following BT. The relationship between the radiation dose of BT and ED in these patients is not well known.

This study involved 48 patients with PCa who received BT. All patients had good sexual functions at the beginning of the study. Patients received different doses of BT, different number of seeds implanted in different places of the prostate. These differences depended on the size of the prostate, location of the tumor, and PSA value. The average follow-up time was 44 months. A standardized questionnaire was used to evaluate erectile function.

The average total sexual function scores decreased from 49.9 at the beginning to 34.7 within 12 months of BT and stabilized at 36 months. Erectile function decreased in 66.7% of the patients after 36 months of BT.

Increasing age was associated with a higher risk to have ED. The average age of patients with a decreased sexual function was 69 years compared to 62 years of the group with preserved function. Also, patients with a higher radiation dose to the prostate apex (the lower part of the prostate directed downward) were more likely to have a decreased sexual function after BT.

This study concluded that older age and a higher radiation dose to the prostate apex area contributed to the lowering of sexual function in patients with PCa.

The study population was small. Whether the radiation doses affected other structures like the penis was not evaluated.