Radiation Therapy Side Effects

Radiotherapy is the second common approach to treating prostate cancer. It is usually used to treat localized or locally advanced prostate cancer and can be used alone or with other treatments.

Radiation therapy uses high-energy waves to kill cancer cells.

There are two main types of radiation therapy for treating prostate cancer, including internal radiation (brachytherapy) and external beam radiation. Randomized clinical trials have shown that prostate cancer patients experience favorable outcomes following radiotherapy (i.e., improved survival and reduced risk of disease progression).

Radiation therapy, like many medical procedures, can have side effects. In particular, radiation may cause severe damage to healthy cells and tissues near the pelvic area.

These problems are different for each patient, depend on the radiation dose and your general health. Here, we discuss the common side effects of radiation therapy in the treatment of prostate cancer. We extend the discussion on the relationship between radiotherapy and sexual function to help you consider the best treatment for your cancer.

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How long do side effects last?

Like other prostate cancer treatments, radiation therapy causes a range of side effects. These side effects usually vary in severity and duration across individuals. There are two broad groups of radiation side effects, including early and late symptoms.

Early side effects such as fatigue, skin changes, and mild digestive tract problems are usually short-lived. They may start during treatment and last for weeks after treatment, but you get better. By contrast, late side effects, such as impotence, erectile dysfunction, and vascular changes in the pelvic area, may take years to develop and often challenging to treat.

It is noteworthy that it is impossible to predict how radiation will affect you and how long your symptoms will last. You may have few or mild side effects that last for a short period, and others may have severe complications or long-term problems.

Common general side effects of radiation therapy

The main concern with radiotherapy is the side effects that develop due to irradiation of healthy cells around the prostate gland. Damage to nearby organs and tissues are unavoidable during radiation therapy for prostate cancer. Thus, it can impair the normal function of the urinary and reproductive systems.

Some of the common side effects experienced by prostate cancer patients during and after radiotherapy are as follows:

Urinary Function:

Urinary tract complications are the most common side effects of many therapies used to treat prostate conditions. Radiation therapy can irritate and obstruct the bladder and urethra to cause urinary dysfunction. These side effects relate to radiation-induced inflammation and mucosal loss at the bladder neck and within the urethra. The symptoms will usually start within two weeks of treatment and continue post-treatment until the affected tissues are repaired.

In a toxicity study involving 204 men treated by radiation therapy, more than 35% of the men reported obstructive symptoms (Pinkawa et al., 2008). However, their symptoms resolved within two months after treatment.

Factors like a large prostate volume due to an underlying benign prostatic hyperplasia may increase the urinary symptom, its severity, and duration. In some patients, long term side effects may develop due to changes in the shape and formation of blood vessels in the irradiated tissues.

This vascular change can reduce the amount of oxygen in the affected tissues, causing hypoxia. Further, men who have previously received transurethral resection have an increased risk of urethral stricture following radiotherapy. Troublesome urinary symptoms may require additional management by alpha-blockers (tamsulosin) or by anticholinergics.

Gastrointestinal side effects:

Sometimes radiotherapy for prostate cancer may inflame the intestine, especially the rectal wall, leading to gastrointestinal side effects such as diarrhea, nausea, bleeding, and ulceration. During the treatment sessions, men have an increased risk of rectal urgency. Long-term, you may experience bleeding and ulceration due to increased inflammation and loss of the rectal wall.

In advanced prostate cancer, patients may receive radiation to the pelvic lymph nodes to treat metastasis. This procedure increases the volume of the bowel irradiated and the subsequent severity of the side effects. Here, more than 30% of the men experience moderate to severe dysfunction, including hematochezia, rectal urgency, and need for a surgical remedy (Crook et al., 1996).

Generally, radiation-induced rectal complications increase in severity during the first two years. It is crucial to seek immediate medical attention if you experience gastrointestinal side effects. Rarely, some men develop permanent bowel complications. Adhering to the pre-radiation diet prescribed by your doctor can promote healing.


Radiation can kill both cancer and healthy cells, especially circulating red blood cells that carry oxygen. Most patients will experience fatigue, which gets worse as the treatment proceeds. However, the fatigue usually resolves after the treatment.

Sensitive skin:

Skin changes are another side effect associated with radiation therapy. You may experience blistering, dryness, and burn during and after treatment. These skin problems will affect patients differently, ranging from mild to severe effects. You will usually feel better immediately after treatment.


Radiation therapy may increase your risk of infection, such as radiation pneumonitis. It is crucial to seek immediate medical attention if you suspect an infection.

Sexual function:

Radiation to the pelvic area decreases potency in treated patients compared to healthy men. Similarly, radiation damage to penile muscles and nerves reduces blood trapping in the penis and cause erectile dysfunction. This situation is often a late side effect of radiotherapy as more than 50% of men experience problems with erection five years after treatment (Potosky et al., 2004).

Factors such as existing partial potency, diabetes, or previous treatment with androgen deprivation therapy increase the severity of radiation-induced impotence and erectile dysfunction. However, phosphodiesterase inhibitors (e.g., tadalafil) can effectively manage these problems in most affected men (Incrocci et al., 2006).

Second cancers:

In rare cases, irradiation of normal tissues may lead to the development of second cancer. These second cancers mainly affect the bladder and the rectum. Advancement in the targeted delivery of radiation treatment for prostate cancer has helped reduce this risk.

Many of these side effects will affect men differently, depending on their previous treatment, prostate volume, underlying conditions, stage of cancer, the extent of the treatment (dosage), and delivery method (external or internal approaches).

Most of the side effects of radiotherapy, especially the early symptoms, are temporary that improve after treatment. Sexual and gastrointestinal symptoms usually occur late and may require additional treatment. Consulting with a healthcare professional is crucial before making decisions about your treatment plan.

How sex might be affected

Radiation therapy to your pelvic region can harm your reproductive system. It can kill nerves and damage blood vessels that control erections. Men treated with radiation therapy have reported problems with erection and potency. However, after a few years, the rate of erectile dysfunction in men treated with radiotherapy is similar to the rate in men treated by surgery.

In comparing different types of radiation therapy for prostate cancer, studies on the rate of erectile dysfunction in brachytherapy and external radiation therapy reported conflicting results. Some studies found that erection problems are lower after brachytherapy compared to external beam radiation. Other studies have found that rates were not different between the two ways of delivering radiation therapy treatment.

Radiation-induced sexual problems usually develop over time, leading to the worsening situation of reduced sex drive, erectile dysfunction, and impotence. If you intended to have children, it is crucial to speak to your doctor about the advantages and disadvantages of the different types of cancer treatment. Like surgical treatment, radiation-induced sexual impairment can be managed by additional therapies such as drugs, implants, and other corrective surgeries.


Radiotherapy is a common treatment for localized and locally advanced prostate cancers. In recent times, significant clinical and technological developments have helped improve its efficacy and radiation therapy side effects rate/severity. These improvements derive from the fact that radiotherapy for prostate cancer is now more targeted and only used in patients who will benefit from treatment.

However, prostate cancer patients treated with radiotherapy still experience some long- and short-term side effects. Specifically, radiation therapy can affect different aspects of your sexual function, including reduced libido, erectile function, and impotence.

Your doctor will usually assess these adverse effects before deciding if radiation therapy is the best treatment option for your cancer. They will also consider other factors, such as tumor grade, metastasis, age, existing medical conditions, and previous treatments. These factors have been shown to influence the severity of treatment side effects.

When you get radiation therapy, you’ll work with a doctor who specializes in this type of medicine. It’s important to talk with them and your cancer care team about how the treatment might make you feel and what you can do to feel better. Inform them if the therapy makes you uncomfortable. They can help you get through your cancer care and treatment.

Do speak to your doctor about your unique satiation to help you decide if other treatment options will work best, especially non-invasive methods. Treatment is vital as untreated early-stage prostate cancer may progress to advanced disease, spreading to your lymph nodes and bones. This advanced stage of prostate cancer is not curable by current treatment methods.

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  1. Crook, J., Esche, B., Futter, N., 1996. Effect of pelvic radiotherapy for prostate cancer on bowel, bladder, and sexual function: the patient’s perspective. Urology 47, 387–394.
  2. Giberti, C., Chiono, L., Gallo, F., Schenone, M., Gastaldi, E., 2009. Radical retropubic prostatectomy versus brachytherapy for low-risk prostatic cancer: a prospective study. World J. Urol. 27, 607–612.
  3. Incrocci, L., Slagter, C., Slob, A.K., Hop, W.C., 2006. A randomized, double-blind, placebo-controlled, cross-over study to assess the efficacy of tadalafil (Cialis®) in the treatment of erectile dysfunction following three-dimensional conformal external-beam radiotherapy for prostatic carcinoma. Int. J. Radiat. Oncol. Biol. Phys. 66, 439–444.
  4. Kagan, A.R., Schulz, R.J., 2010. Proton-beam therapy for prostate cancer. Cancer J. 16, 405–409.
  5. Law, A., McLaren, D., 2010. Non-surgical treatment for early prostate cancer. J. R. Coll. Physicians Edinb. 40, 340–2.
  6. Pinkawa, M., 2010. External beam radiotherapy for prostate cancer. Panminerva Med. 52, 195–207.
  7. Pinkawa, M., Fischedick, K., Asadpour, B., Gagel, B., Piroth, M.D., Nussen, S., Eble, M.J., 2008. Toxicity profile with a large prostate volume after external beam radiotherapy for localized prostate cancer. Int. J. Radiat. Oncol. Biol. Phys. 70, 83–89.
  8. Potosky, A.L., Davis, W.W., Hoffman, R.M., Stanford, J.L., Stephenson, R.A., Penson, D.F., Harlan, L.C., 2004. Five-year outcomes after prostatectomy or radiotherapy for prostate cancer: the prostate cancer outcomes study. J. Natl. Cancer Inst. 96, 1358–1367.

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