Radiation Treatments

Radiation Treatments

The two major radiation treatments are:

• External-beam radiation
• Brachytherapy

Both treatments have generally equal success rates. Research presented at the 2006 Prostate Cancer Symposium indicated that the two therapies work equally well for treating localized prostate cancer. In some cases, both techniques may be used in high-risk patients.

External-Beam Radiation

In external-beam radiation therapy, a doctor focuses a beam of radiation directly on the tumor for 35 3-minute treatments given 5 times a week over 7 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 doctors, 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 suggest that 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. Poorer candidates for brachytherapy include men who have had TURP and patients with advanced cancer, high-grade tumors, or very enlarged prostate glands.