Radiation therapy is also a proven treatment for prostate cancer. The goal is to deliver the highest possible doses of radiation to the prostate while minimizing the amount of radiation to surrounding structures, including the bladder and rectum. There are various methods of delivering radiation to the prostate to kill the cancerous cells and not all types of radiation may be appropriate options for all patients. Hormonal ablation therapy may need to be given with radiation therapy depending on the aggressiveness of the prostate cancer. In addition, sometimes radiation is used after surgery (adjuvant radiation) for more aggressive cancers or for cancer recurrence (salvage radiation).
Like surgery, side effects after radiation treatment can include urinary and erectile problems. In addition, patients may rarely experience bowel problems such as rectal bleeding or pain, diarrhea or fistula (formation of a connection between the rectum and urinary tract). Due to radiation, there is a small potential increased risk for development of secondary cancers of the bladder or rectum.
Advantages: Avoids the risks of major surgery for patients particularly those who are at higher risk to undergo surgery due to other medical problems or who simply wish to avoid an operation. It is a proven treatment with durable long-term results for treatment of men with prostate cancer.
Disadvantages: As previously mentioned, there are potential side effects including urinary, erectile and bowel problems. PSA surveillance after treatment is somewhat more complicated than after surgery, and therefore, cancer recurrences may be more difficult to detect. The prostate and/or lymph nodes are not fully evaluated since the prostate and lymph nodes are not removed for microscopic examination.
Types of Radiation Therapy
External Beam Radiotherapy
External beam radiation involves using beams of gamma radiation (usually photons) directed at the prostate and surrounding tissues through multiple fields. To minimize radiation injury to the bladder and rectum, three-dimensional conformal techniques and now, (IMRT) have been developed to accurately target the highest doses of radiation to the cancerous areas of the prostate and lower the doses near the bladder, rectum and urethra. Most patients with localized or locally advanced prostate cancer are candidates for external beam radiation. It is usually administered every day (five days per week) for five to eight weeks, depending on treatment dose.
Brachytherapy (Radiation Seed Implantation)
Brachytherapy or radiation seed implantation involves the placement of radioactive seeds directly into the prostate gland. These radiation sources then continue to administer radiation to the prostate over a period of time. Sometimes radiation seeds may be used in conjunction with external beam radiation therapy for more aggressive cancers.
Brachytherapy requires an outpatient procedure in the operating room and most patients can go home the same day and resume normal activities within 48 hours. Patients with more aggressive prostate cancer, large prostates or those patients with lot of baseline urinary symptoms are not appropriate candidates for brachytherapy.
Proton Beam Therapy
Proton beams are an alternative source of radiation to treat prostate cancer. There are some theoretical advantages for proton beam radiation although it has not been demonstrated to provide any true clinical advantages over standard radiation treatments listed above. Due to its increased cost and lack of clinical data, it is not recommended for routine use at this time.
Stereotactic Body Radiotherapy
Stereotactic radiotherapy is a promising radiation technique using highly-focused beams to achieve precise targeting. Its advantage is that it may allow treatments to be performed in five or fewer treatments. This treatment is considered investigational with no long-term data about its effectiveness or toxicity, so it is not recommended for routine use outside of clinical trials at this time.