Because the prostate is close to several vital structures, radiation therapy can disrupt normal urinary, bowel, and sexual functioning.
You may experience some temporary urinary symptoms, such as waking up in the night and needing to urinate, needing to urinate more often during the day, or urgency – needing to urinate right now, and not being able to hold it in for a long time. Tell your doctor; there are medications that can help reduce acute symptoms. You may also experience some rectal problems, including the need to have a bowel movement more often than usual, or loose stools. Diarrhea is rare, but if needed, there are medications that can help. Your doctor may also suggest that you try a low-fiber diet for a while.
The risk of long-term problems after radiation therapy is very low, less than 5 percent. These may include proctitis (rectal inflammation), cystitis (bladder inflammation), urinary or rectal bleeding, narrowing of the rectum or urethra, chronic diarrhea or urinary frequency or urgency, or development of an ulcer in the rectum. All of these can be treated.
Similar to surgery, damage to blood vessels and nerves after radiation therapy can result in decreased erectile function over time. In general, radiation therapy has less of an impact on erectile function in the first 5 to 10 years after treatment compared with surgery, and approximately 70%
of men who have baseline erectile function before treatment will keep erectile function after treatment. However, radiation therapy has a slower delay in erectile function decline than surgery; 15 years after treatment, the rates are similar to those who underwent surgery.
These rates do not appear to be affected in the long-term by the use of short-term (4 to 6 months) hormone therapy, but will be affected by the use of long-term (18 to 36 months) hormone therapy.
Newer techniques in radiation therapy, termed “vessel sparing” radiation therapy, have shown promising results for improving the preservation of erectile function, with close to 80% of men maintaining baseline function. Ask your radiation oncologist about vessel sparing radiation therapy.
There are also fertility impacts from radiation therapy.