RADIATION TREATMENT OF PROSTATE CANCER AFTER SURGERY
Radiation can be either postprostatectomy adjuvant radiation therapy or salvage radiation therapy. Adjuvant refers to a therapy that modifies the effect of another therapy. In this case, the adjuvant radiation therapy improves the results of the surgery. A positive surgical margin has a 50% chance of prostate cancer recurrence. A positive surgery margin means cancer was found in the edge of the removed prostate and a negative margin means that no cancer was found at the edges of the prostate by the pathologist specimen. Recurrence is more likely if there is extension of the cancer into surrounding tissue including the seminal vesicle and a Gleason of 7 or higher. Our center uses postprostatectomy adjuvant radiation IMRT to improved PSA free survival after surgery if the pathology suggests a higher recurrence rate may be predicted.
If there is a recognized cancer recurrence after surgery, radiation is referred to as salvage radiation therapy. Between 15% and 25% of men who had a radical prostatectomy will have a detectable PSA with 10 years of the surgery. In this situation (detectable PSA after surgery), metastatic disease is initially looked for with bone scan, chest X-ray, and CT or MRI of the abdomen and pelvis. If these are normal, then it may be assumed the disease is in the bed of the prostate. Assuming the cancer is present in the pelvis where the prostate used to be is accomplished by ruling out the presence of any metastatic disease.
In these two situations, the dose of radiation is less than what would be delivered if the prostate were being treated for the first time. This reduction is because the overall target (prostate) is not present and because the bladder and surrounding tissue will not tolerate radiation as well after surgery. Occasionally, adjuvant hormonal therapy is added. A customized treatment plan is derived from collaboration between the Urologist and the Radiation Oncologist
Question: Are there side effects from radiation treatment of prostate cancer after surgery?
Answer: Yes. The side effects are a little more frequent than those seen after radiation or surgery alone. These side effects include frequency, urgency to void, nocturia (getting up at night to void), increased bowel movements, blood in the urine and stool, and worsening of erectile function. However, the degree of the side effects is not usually severe. The risk/benefit ratio weighing the risks of the side effects and the benefit of the cancer control is in favor of treatment. In general, men receiving radiation therapy after surgery experience few additional problems.
Question: How effective is the radiation after surgery?
Answer: Postprostatectomy adjuvant radiation can reduce the PSA occurrence after surgery by half. The PSA returns to zero in about 25% of men treated with salvage radiation therapy.
Question: What happens if the PSA does not stabilize or reduce after radiation?
Answer: Most often, microscopic metastatic disease was too small to be detected by bone scan, CT or MRI before radiation.