Before discussing side effects from radiation treatment for prostate cancer (PCa) it’s important to remember that no intervention for localized PCa is 100% free from risks. This includes surgery, radiation, and focal therapy. However, the odds of side effects vary among the methods.

Some procedures have greater side effect rates than others due to the degree of intrusion into the prostate bed. The greater the intrusion, the more likelihood of collateral damage. Thus, whole gland treatments generally increase the chance of harm to nearby structures (bladder, muscles that control urine flow, bowel wall, and the nerve/blood vessel bundles that control erections). Every doctor’s goal for his/her PCa patients is to maximize the ability to conquer cancer while minimizing treatment impact on quality of life. In fact, we’re now at the best point in history for planning treatment because today’s advances give us two great advantages:

• A thorough portrait of each individual’s localized tumor thanks to multiparametric MRI, MRI guided targeted biopsy, diagnosing the nature of the tumor cells, and correlating biopsy results with the imaging and with biomarkers like genomics or circulating tumor cells.
• A growing menu of treatments that can be tailored to the disease, the patient’s anatomy, any co-existing health conditions, and lifestyle preferences.

In other words, we now know the nature of the enemy as never before, and we now have a range of weapons to use against it. Thus, we can match treatment to the disease as never before.

Why radiation has unique side effect risks

For some patients, radiation will be the best treatment match. However, it differs qualitatively from the others because its effects cannot be known immediately. Whether it is radiation by external beam or by radioactive seed implants, radiation does not kill PCa all at once.

Instead, radiation exposure slowly damages each cancer cell’s DNA so the cells can’t reproduce, and they gradually die off. The exposure has to be maintained over time, since the less hardy cells will die off first while the more resistant and aggressive cells need the constant pressure of exposure. Does radiation affect healthy cells? Well, yes, to a certain extent, but normal cells are more resilient and much less prone to the bombardment of radiation on their DNA. Still, the “scatter effect” of radiation can influence healthy cell mechanisms, so the dose and duration of radiation are carefully calculated to minimize risks to healthy tissues while delivering a lethal punch to cancer cells.

This gradual die-off can take many months. Meanwhile, there is no way to “visualize” how well radiation is working. Even the most sophisticated imaging can’t show the slow cell death as it’s happening. As tumor cells die, and the tumor shrinks away, the PSA that was put out by the cancer cells diminishes until it reaches its lowest point, called the nadir. In many cases, the PSA has a “bounce” or spike before it settles down at its nadir. This is why radiation patients have frequent PSA blood tests to monitor the destruction.

Early and late onset side effects

It’s common for PCa patients who have radiation to have increasing side effects during and shortly after the treatment. Usually, the effects are mild and may be somewhat inconvenient: urinary irritation (frequency, difficulty, leakage), bowel irritation (diarrhea, rectal bleeding, painful bowel movements), abdominal cramping, fatigue). While some symptoms quickly subside after treatment, some may appear a few months later before returning to normal. These are early side effects, and patients should not be concerned but should communicate with their doctors.

However, there is more concern about possible side effects that show up much later, even years later, due to radiation damage to healthy structures. Similar to the short-term, immediate side effects, the later symptoms include urinary and bowel problems, but often to a worse degree. A research team at UCLA recently published a study connecting the degree and duration of early symptoms with worse late onset symptoms. According to a medical news article about the study, “Late urinary toxicities [side effects] include narrowing of the urethra and having blood in the urine. Late bowel toxicities include having blood in the stool or having an ulcer in the wall of the rectum. These issues often can have a bigger impact on a person’s quality of life compared to acute side effects.”

Therefore, clinical studies are being done to determine if reducing early side effects can help prevent later side effects. This includes both preventive measures as well as treating early side effects if they appear. Three key areas for prevention are:

1. Using multiparametric MRI to identify the location, size and shape of the tumor in order to plan radiation delivery in more targeted fashion;
2. Radiation technologies that are more able to be targeted, such as stereotactic body radiation therapy (SBRT);
3. Rectal spacers like a harmless gel that can be injected into the tissue between the gland and the rectal wall to widen the space and reduce radiation exposure on the bowel.

As for treatments, medications that can relax bladder muscles (better urine control) or reduce diarrhea and bowel pain can be prescribed. For local discomfort, patients can use over-the-counter pain relievers. Drinking plenty of healthy fluids while avoiding caffeine and alcohol may also help with bladder irritation, and eating a healthy diet and getting plenty of good sleep is well advised in any case.

Finally, for patients with localized PCa who prefer not to have radiation, targeted focal laser ablation or other non-radiation focal therapies like TULSA may be an option. Since they spare healthy prostate tissue, they lower side effects rates. For more information, contact the Sperling Prostate Center.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.