External beam radiation will be applied in all stages of prostate cancer, however, particularly in cases of advanced tumors. It is also used for pain management in cases of metastasis.
For some time, external radiation therapy was regarded as a less effective alternative
for the removal of the prostate. Today’s technology is advanced to a point that high radiation doses in combination with simultaneous protection of neighboring organs are an effective alternative. The therapy is very time consuming, since the total required dose is administered daily in about 40 sessions for over eight weeks.
In the same way as brachytherapy, the course of treatment always starts with a planning of the radiation at the computer. Sophisticated computers are used to precisely map the location of the prostate tumor and to calculate the optimal doses needed to the tumor while simultaneously sparing the surrounding tissues. The results of the planning are transferred at a therapy simulator to the skin of the patient using special markings. This confines the radiation precisely to the areas where it is needed. Custom-designed shields help protect nearby normal tissue. Radiation treatments are generally given five days a week for about six to eight weeks on an outpatient basis.
The side effects are moderate: In comparison with brachytherapy, there is more frequent local irritation of the bladder and rectum, which, however, usually subsides after the end of the treatment