Radiation therapy is a common and effective treatment for localized prostate cancer. However, the process can impact nearby healthy tissues, leading to long-term or late side effects that manifest months to years after treatment completion. Two primary methods of treatment are used: External Beam Radiation Therapy (EBRT), which delivers radiation from an external machine, and Brachytherapy, which involves implanting radioactive seeds directly into the prostate gland. Understanding these potential long-term changes is an important part of post-treatment care and survivorship.
Long-Term Effects on the Urinary System
The prostate gland is located immediately beneath the bladder and surrounds the urethra, making the urinary system particularly susceptible to radiation effects. Over time, radiation exposure can cause inflammation and scarring of the bladder lining, a condition known as radiation cystitis. This scarring reduces the bladder’s ability to stretch and hold urine, leading to increased urinary frequency, urgency (a strong, sudden need to urinate), and nocturia (the need to wake up at night to void).
Damage to the sphincter muscles or the urethra itself can result in involuntary urine loss, known as incontinence. This leakage may manifest as stress incontinence, where urine escapes with physical strain like coughing or sneezing, or urge incontinence, which is leakage following a sudden, intense need to go. Less commonly, scarring in the urethra can cause a urethral stricture, a complication which can impede the flow of urine and make voiding difficult.
Persistent Gastrointestinal and Rectal Changes
The rectum, a part of the lower gastrointestinal tract, sits directly adjacent to the prostate, placing it within the radiation field. Long-term irritation and damage to the rectal lining can result in chronic radiation proctitis. This inflammation often causes intermittent rectal bleeding, which is typically due to fragile, dilated blood vessels called telangiectasias.
Patients may also experience long-term changes in bowel habits, including chronic diarrhea or the frequent, urgent need to pass stool. Another specific symptom is tenesmus, a cramping sensation accompanied by the feeling that one needs to pass stool even when the bowel is empty. In some cases, the radiation damage can affect the nerves and muscles controlling the bowel, leading to fecal incontinence, where control over gas or stool is compromised.
Impact on Sexual Function
One of the most common long-term effects of prostate radiation is a decline in sexual function, primarily manifesting as Erectile Dysfunction (ED). Unlike surgical treatments where ED is immediate, radiation-induced ED tends to develop gradually over time, often beginning months to a year after treatment and worsening progressively over a period of up to two years. This delayed onset is related to slow, progressive damage to the tiny blood vessels and nerves surrounding the prostate.
The radiation can still cause fibrosis, or scarring, within the penile tissue and blood vessels, ultimately reducing blood flow. Approximately 25% to 50% of men who were potent before treatment may experience ED following radiation therapy. In addition to difficulty with erections, some men may also notice changes in ejaculation, such as dry orgasm or a reduced volume of semen.
Management Strategies for Chronic Symptoms
A range of medical and lifestyle interventions are available to manage the persistent long-term symptoms that can arise after radiation treatment. For chronic urinary issues, simple measures such as dietary changes and pelvic floor muscle exercises, commonly known as Kegels, can help improve control and reduce leakage. When symptoms like urgency and frequency are bothersome, medications such as alpha-blockers or anticholinergics may be prescribed to relax the bladder muscle or improve urine flow.
For gastrointestinal and rectal symptoms, management often starts with adjustments to diet, such as increasing or decreasing fiber intake depending on whether the primary symptom is diarrhea or constipation. Persistent rectal bleeding caused by radiation damage can be treated directly using minimally invasive procedures like argon plasma coagulation (APC), which uses heat to seal the bleeding vessels. Severe cases of radiation proctitis that do not respond to standard care may be treated with hyperbaric oxygen therapy (HBOT), which promotes tissue healing.
Erectile Dysfunction is commonly managed initially with oral medications called PDE5 inhibitors, such as sildenafil or tadalafil, which help the penile blood vessels relax and fill with blood. If these medications are insufficient, other options include using a vacuum erection device or self-administering penile injection therapy. Early intervention with these therapies, sometimes called penile rehabilitation, is often recommended to maintain tissue health and maximize the chances of recovering function.
Extremely Rare but Serious Late Complications
While the functional changes to the urinary and bowel systems are more common, a few serious complications can occur, although they are statistically rare. One such risk is the development of a secondary malignancy, such as bladder or rectal cancer, which may arise many years—often more than ten—after the initial radiation treatment. The absolute risk of developing a second cancer due to the radiation is very low, but it remains a consideration for long-term survivors.
Severe urethral strictures, which are extreme narrowings of the urinary tube, represent another rare but difficult complication that may require surgical intervention. Furthermore, if the radiation field included lymph nodes in the pelvis, a small number of individuals may experience chronic lymphedema, which is persistent swelling, typically in the legs or genital area, due to impaired lymphatic fluid drainage.