FAQ: Radiation Therapy for Prostate Cancer

Why would I choose radiation therapy?

Radiation therapy, including external beam radiation therapy (EBRT) and brachytherapy, is an alternative form of treatment for prostate cancer. EBRT may be used after other treatments, such as surgery, to manage cancer that has recurred or is at high risk of recurrence. Radiation therapy has an excellent record of success, providing long-term disease control and survival rates equivalent to other treatments, including surgery.

How should I expect to feel during radiation therapy?

Undergoing external beam radiation therapy (EBRT) is similar to having a routine X-ray. Radiation cannot be seen, smelled or felt. Generally, side effects don't appear until the second or third week of treatment. Because radiation therapy is a local treatment, only the areas of the body where it is directed will experience side effects. Most patients will experience some or all of the following:

  • Increase in the frequency of urination
  • Urinary urgency
  • Weak urinary stream
  • Difficulty starting urination
  • Burning or tingling with urination
  • Occasional diarrhea
  • Softer and smaller volume bowel movements
  • Increased frequency of bowel movements
  • Worsening of hemorrhoids or rectal irritation with occasional scant blood and fatigue

Depending on the severity of these side effects, you may be prescribed medications such as anti-diarrheal medication (Immodium AD or Lomotil) or a medication to decrease the frequency of urination (Flomax or Uroxatral) for symptom relief. Most of these symptoms are short-term and go away after the radiation therapy ends. The time for full recovery depends on the patient and the type and severity of urinary or bowel symptoms, and whether the patient had any symptoms before treatment.

As part of your treatment planning, you will be asked to fill out questionnaires to help evaluate your bladder function. It is important to discuss the nature and severity of your particular symptoms with your doctor, since this may influence your treatment course. Patients typically continue with their normal daily activities during treatment.

On occasion, the external beam radiation therapy (EBRT) treatment machines go down, meaning treatment cannot be delivered. This can occur unexpectedly and for a variety of reasons. If any aspect of the machine's normal functioning is irregular, a safety feature kicks in and treatments cannot be given. When this happens, you may be asked to have treatment on another machine, wait until the problem is resolved, or skip treatment that day if a longer evaluation and repair time is needed. If you miss a treatment, it will be rescheduled so that you receive the prescribed dose of radiation.

Many questions may arise during radiation therapy treatment. Your doctors will be available to answer questions throughout your treatment.

How should I expect to feel after radiation therapy?

External Beam Radiation Therapy (EBRT)

After completing external beam radiation therapy (EBRT), urinary and bowel side effects may persist for two to six weeks, but they will improve over time. You may need to continue some medications.

Some patients report continued, though lessening fatigue for several weeks after treatment. Other minor problems may include dry itchy skin, a sensation of heaviness in the perineum, anal and rectal irritation, and flare-up of hemorrhoids. However, patients are usually well enough to continue with normal daily activities.


Brachytherapy is a form of radiotherapy where a radioactive source is placed inside or next to the area requiring treatment. For example, in some cases, small radioactive pellets, often called "seeds," each about the size of a grain of rice, are implanted into the prostate. Another type of brachytherapy involves inserting needles to administer radioactive material, such as iridium, for relatively short periods of time.

After brachytherapy, patients may experience the following symptoms:

  • Burning with urination
  • Increased frequency of urination
  • Slow or weak urinary stream
  • Incomplete emptying of the bladder
  • Brief period of blood in the urine, usually immediately after the procedure
  • Perineal pain or soreness
  • Scrotal bruising or swelling
  • Blood spotting from the perineum
  • Nausea from anesthesia
  • Fatigue

Most patients continue with normal daily activities shortly after brachytherapy, although heavy lifting and strenuous physical activity should be limited for two to three days after the implant. In less than 10 percent of cases, swelling of the prostate may cause outflow obstruction of the bladder. In these cases, a patient may go home with a Foley catheter and be prescribed medicine to help reduce swelling and inflammation.

In rare instances, patients can't urinate several hours to a day after going home. In this event, you should visit your doctor or the nearest emergency room so a Foley catheter can be placed. The catheter usually can be removed after three to seven days.

Some patients may experience rectal discomfort after the procedure. Rectal bleeding is uncommon.

What can I do about side effects?

  • Fatigue — Fatigue may occur later in radiation therapy treatment. Consider taking a nap during the day. If working, consider decreasing work hours or taking a leave, if possible. However, try to maintain a level of physical activity and a well-rounded diet. Nutritionists are available to provide assistance if desired. Contact your doctor if fatigue becomes severe.
  • Diarrhea, flatulence or painful defecation — These symptoms usually occur after the second or third week of treatment. Symptoms will resolve after the treatment ends. During radiation, dietary modification usually helps reduce the frequency and severity of diarrhea. Try to avoid or reduce fried foods, greasy foods and highly spiced foods. Reduce foods with insoluble fiber, such as lettuce and cauliflower, and increase low-fiber and soluable-fiber foods, such as bananas, mashed potatoes, applesauce, white rice, canned or cooked fruits and vegetables.

    Maintain your intake of lean proteins, such as turkey, chicken and fish, and increase your fluid intake to avoid dehydration. Using moist toilet paper, baby wipes or sitz baths may help relieve rectal irritation. Your doctor may recommend anti-diarrheal medications. Contact your doctor if you see blood in your stool, if the diarrhea worsens or if you become light-headed or dizzy.
  • Frequent urination, burning with urination and difficulty urinating — These are the most common complaints. Occasionally the urinary stream will weaken. Generally these symptoms are managed with medications to help the bladder function better or eliminate burning. Rarely, your doctor may order a urine test. Symptoms will resolve after the end of treatment. Contact your doctor if you see blood in your urine or if you are unable to urinate.
  • Swelling, bruising or tenderness of the scrotum — Symptoms generally resolve on their own within three to five days. Oral anti-inflammatory medications such as ibuprofen are usually sufficient for pain relief, if necessary. You should avoid hot tubs and Jacuzzis for at least two to three days after the procedure. Postpone bike riding until the tenderness is gone.
  • Skin irritation — This is uncommon, but if it occurs, do not rub or scratch the area. Avoid clothing that rubs and avoid alcohol-containing lotions or colognes. Your doctor can recommend a skin care regimen and topical creams or lotions to relieve the symptoms. Contact your doctor if you develop a rash all over your body.

What special issues should I be aware of?

Before you go home, you will be given detailed written instructions about the following issues:

  • Radiation safety — There is no remaining radiation in your body once your treatment is complete and it is completely safe to be around other people.

    If you are treated with permanent seed brachytherapy, the radiation from the implant is absorbed by your tissues. Neither bodily waste nor items that come into contact with you are radioactive. During the first one to two months after permanent seed implantation, you should maintain a distance of six feet or more from women who are pregnant or who may become pregnant if they will be in your company for a prolonged period of time. We also recommend that young children and pets not rest on your lap for prolonged time periods. Sexual intercourse may be resumed at any time after the seed implant but we recommend that you wear a condom during the first week after the procedure.

  • Sexual function — Many men experience a decline in erectile function (erectile dysfunction or impotence) after radiation therapy. The likelihood of impaired potency is influenced by age, which is the primary risk factor, the use and duration of hormone therapy, smoking and medical conditions, such as hypertension and diabetes, as well as the medications used for their treatment. For most men, erectile function declines slowly over the first two years after treatment.

    The effects of short-term hormone therapy (four to six months) appear to be largely reversible. Similar levels of sexual function are reported at four years by patients who received hormone therapy and patients who did not receive hormone therapy. Patients may develop some degree of erectile dysfunction after brachytherapy. Treatment-related erectile dysfunction may be less likely after brachytherapy than other forms of treatment. Most men who are not taking nitrate-containing medications can use any one of the oral medications on the market that improve erectile quality with excellent success.

    Patients may experience a prolongation of the time to orgasm. Some experience a change in the nature of their ejaculate, such as thicker and less fluid, a decrease in the quantity or an absence of ejaculate after radiation treatment, more so with EBRT than brachytherapy. Following brachytherapy, the ejaculate may be discolored, such as dark-brown or even black. This discoloration is due to "old" blood that may have resulted from the procedure. It is harmless to you and your sexual partner. The ejaculate will clear.

  • Sperm production — Sperm are produced in germinal cells in the testicles. During prostate radiation, low levels of "scatter radiation" that originate inside the patient's body can reach the testicles and decrease sperm production. The dose of radiation that reaches the testicles usually leads to a temporary reduction (months to years) in the sperm count. However, it is possible to have a permanent reduction in the sperm count or sterility. If you are considering fathering additional children, you may wish to seek medical advice regarding your fertility and need to bank sperm.
  • Testosterone production — Testosterone is secreted by the Leydig cells in the testicles. Generally, the doses of internal scatter radiation that reach the testicles are not high enough to impair Leydig cell function.

How often will I need to see my doctor for follow-up?

Following external beam radiation therapy (EBRT), you will have an initial appointment to make sure that treatment-related side effects are diminishing or have gone away.

The frequency of follow-up appointments will be based on the risk of cancer recurrence. In general, serial PSA blood tests will start around the third month after treatment completion. Testing typically occurs every three to four months during the first two to three years after treatment completion and then every six months thereafter. Changes to this schedule may be made during the process of follow-up evaluation.

Patients receiving brachytherapy will have an appointment for a CT scan of the prostate approximately three to four weeks after the procedure. This CT scan will be used to evaluate the quality of the implant. Generally on the same day, an appointment in the Urology Department will also be scheduled.

How will I know if the treatment is working?

Serial PSA blood tests will be used to monitor your progress after definitive treatment of your prostate cancer. Following radiation therapy, your PSA will fall but will not reach its lowest value, or nadir, immediately after treatment. Though infrequent, it may take up to two to three years for the PSA to reach its nadir.

Keep in mind that the PSA may not decline steadily. Temporary increases in PSA, also called "spikes" or "bounces," may occur during the first 12 to 36 months after external beam radiation therapy (EBRT) or brachytherapy. These bounces are not signs of treatment failure.

If you received hormone therapy, the PSA decline and the period of decline may be prolonged. As your testosterone recovers, your PSA may rise. This increase is not considered a "bounce or spike" and is not a sign of treatment failure.

There is much debate over the most accurate means to detect treatment failure after radiation therapy. A consensus definition was established in an effort to systematize the evaluation of treatment outcomes. This definition defines treatment failure as three consecutive increases in the PSA value after the nadir has been reached. There are several problems with this definition. Also, the consensus definition was intended to be used after EBRT monotherapy, not after brachytherapy or combined treatment with hormone therapy, as it is sometimes used.

A task force is working to define a more sensitive (accurately detects increases in the PSA) and specific (the detected PSA rises truly represent treatment failure) definition for post-EBRT therapy, as well as establish definitions for treatment failure following brachytherapy and combined radiation and hormone therapy.

This does not mean that PSA testing should be abandoned at this time. It remains an important monitoring tool and serial testing at regular intervals is critical to its effective use. Your doctor will evaluate additional data in conjunction with the PSA to monitor your treatment outcome.

Will I need additional treatment?

Usually, no additional treatment is needed after radiation therapy. The need for additional treatment is determined by the PSA, Gleason score and stage of the prostate cancer and having your daily treatments as scheduled, particularly for external beam radiation therapy (EBRT). Regular post-treatment PSA evaluation plays an important role in monitoring and evaluating the need, if any, for additional treatment in the future.

Should the cancer recur, options for treatment will in part depend upon the initial treatment. Additional or alternative forms of radiation therapy, prostatectomy, cryotherapy, hormone therapy or any of a number of treatments under evaluation in clinical trials may be recommended. Your team of doctors, including a radiation oncologist, urologist and medical oncologist, will discuss treatment options and recommendations with you.


Reviewed by health care specialists at UCSF Medical Center.

This information is for educational purposes only and is not intended to replace the advice of your doctor or health care provider. We encourage you to discuss with your doctor any questions or concerns you may have.

Related Information

UCSF Clinics & Centers

Prostate Cancer Center
1825 Fourth St., Fourth Floor
San Francisco, CA 94158
Medical Oncology Phone: (415) 476-4616
Surgical Oncology Phone: (415) 353-7171
Medical Oncology Fax: (415) 353-7107
Surgical Oncology Fax: (415) 514-6195

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