Prostate Cancer

Description

Alternative Names

Radiation Treatments

Two major radiation treatments are now available:

• External-beam radiation.
• Brachytherapy.

Advances in both treatments have been generally equivalent in success rates. In some cases, both techniques may be used in high-risk patients.

External-Beam Radiation

In external-beam radiation therapy, a physician focuses a beam of radiation directly on the tumor for 35 three-minute treatments, five times a week, over seven weeks. 3-D conformal techniques use computers and a three-dimensional image of the prostate to provide precise targeting of the tumor using high-dose radiation beams. It allows high doses and poses a lower risk for inflammation. Men who have had transurethral resection of the prostate (TURP) or have a history of lower urinary tract symptoms may be particularly good candidates for 3D conformal techniques.

Brachytherapy

Brachytherapy is an outpatient technique that implants radioactive seeds directly into the prostate. Implants can be temporary or permanent. Temporary implants are usually accompanied by external-beam radiation. This procedure requires more skill than external-beam radiation therapy, and even with experienced physicians, the distribution of radioactive seeds is uneven in 15% of cases, increasing the risk for insufficient doses.

Computerized systems are being developed to help oncologists optimize seed placement and allow precise treatment for each patient and higher radiation doses. Eventually, it could improve tumor control, reduce side effects, and cut costs.

It is common for PSA levels to temporarily rise, or bounce, following seed implantation without it being a signal for cancer recurrence. This effect can produce anxiety and can interfere with the diagnosis of true recurrence.

Candidates. Studies are indicating the brachytherapy is useful for select patients, specifically those with prostate volumes less than 60 mL and who have early-stage prostate cancer (T1 or T2 tumors, a Gleason grade lower than 7, and PSA levels below 10 ng/mL). It may be beneficial in patients with inflammatory bowel disease or with cancer close to the bowel. Poor candidates for brachytherapy include men who have had TURP and patients with advanced cancer, high-grade tumors, or very enlarged prostate glands.

Complications from Radiation

The side effects of radiation therapy include most of those of surgery, but the risks for impotence and incontinence are considerably lower. A 2000 study concluded that adjuvant radiation therapy (given right after surgery) in moderate doses does not increase the risk for long-term urinary incontinence or sexual dysfunction beyond that of surgery alone.

Gastrointestinal Complications. Complications in the gastrointestinal are common. Short-term effects include nausea and loss of appetite. Diarrhea is a very common side effect and can last for the duration of therapy. It is usually treated with Lomotil. A few patients have diarrhea flare-ups for years afterwards. Less than 1% suffer more serious intestinal problems.

There is potential for injury to the rectum with brachytherapy. Ulcers in the rectum occur in more than 10% of patients, but the risk decreases with greater experience in the technique.

Urinary Problems. The risk for incontinence is about 7% to 20%. Patients treated with radiation may experience a painful, but usually temporary, urinary tract inflammation. About 10% to 15% of patients develop a long-term urgent and frequent need to void their bladder. Brachytherapy carries a lower risk for urinary incontinence.

Scarring and narrowing of the urinary tract (stricture) may occur, particularly in men who had TURP performed within a short time before radiation treatment. In such men, radiation treatments should be delayed by four to six weeks. If the prostate has been injured or damaged or the bladder is easily irritated, side effects with brachytherapy may actually be worse than with other procedures.

Impotence. In a 2003 meta-analysis, the risk for impotence following radiotherapy varied from 25% with brachytherapy to 45% with external beam radiotherapy. Still, very few studies on brachytherapy have lasted more than two years, so more research is needed.

Sildenafil (Viagra) may help many men experiencing impotence following radiation therapy for local prostate cancer. Early use of both alprostadil injections and Viagra may be even more effective. Other treatments may also be useful. [See Well-Connected Report #15 Impotence.]

Experimental Radiation or Other Nonsurgical Procedures

Investigators are testing radiation treatments that use a combination of neutrons and protons (mixed-beam) or proton beams rather than the standard proton radiation therapy. Intensity-modulated radiation therapy is a promising technique that delivers different doses to multiple target areas using images of specific regions.

High-Intensity Focused Ultrasound (HIFU). Studies are reporting promise with an intensive ultrasound procedure called transrectal high-intensity focused ultrasound (HIFU). It allows for very precise minimally invasive removal of tissue in local prostate cancers. It may eventually prove to be an alternative to radiation therapy. More research, with long-term follow up, is needed.

Radiofrequency.Radiofrequency is being used to heat and destroy the prostate. Early studies are indicating that this is a promising approach.