Interstitial radiation is administered by inserting pellets or ribbons of radiation-emitting material directly into the prostate. This can be done by open surgery or via needles inserted through the skin. The main advantage of this therapy is that the radiation dosage is concentrated to the tumor and does not harm normal tissues. There is also less radiation cystitis and proctitis. If the pellets or ribbons are inserted at open surgery, the surgeon can at the same time sample the lymph nodes to see if the tumor has spread (although the use of laparoscopic sampling may make open surgery less common).
The disadvantages of interstitial radiation are that the pellets or ribbons may not be placed evenly in the tumor and areas can be missed. Also, all the cancer cells may not be killed and the tumor may recur. Interstitial radiation can also rarely produce erosion into the rectum causing urine to pass into the rectum and stool into the bladder.
Radiation therapy is also used to relieve symptoms. Radiation to bone for local control of pain, for example, can often produce dramatic relief.
Cryosurgery Freezing of the prostate using a liquid nitrogen probe is a new technique being
studied to treat prostate cancer. It has the theoretical advantages of a rapid effect, little pain and potential eradication of the cancer. However, at this time, it is experimental, since its effectiveness and its side effects are not yet established.
