HOLLYWOOD, FLA. — The use of three-dimensional conformal radiation or intensity-modulated radiation therapy is now mandated in the National Comprehensive Cancer Network's new treatment guidelines for prostate cancer.
Specific recommendations for radiation doses to treat low-, intermediate-, and high-risk prostate cancer have also been added.
“Our decisions are not black and white, and most patients will have multiple options regarding which treatment they wish to pursue,” Dr. Michael R. Kuettel, professor and chair of radiation medicine at Roswell Park Cancer Center, Buffalo, N.Y., said at the NCCN's annual conference.
Risk stratification is extremely important. Past guidelines have included stage, Gleason score, and prostate-specific antigen levels. This year, estimates of a patient's life expectancy have been added to calculate overall risk, said Dr. Kuettel, who is also president-elect of the American College of Radiation Oncology.
As disease risk increases, so should the dose of radiation. For patients with low-risk disease, the guidelines recommend radiation doses of 70–79 Gy and no radiation to the lymph nodes. For intermediate or high risk, the recommendation is for radiation doses of 75–80 Gy, with consideration of pelvic lymph node external beam radiation therapy or androgen deprivation therapy.
Increasing the dose of radiation produces better outcomes, but it also has the potential for increasing side effects, said Dr. Kuettel. One way to minimize radiation toxicity is to use three-dimensional conformal radiation or intensity-modulated radiation therapy. Another is to locate the position of the prostate on a daily basis.
“With dose escalation, one needs to confine the dose very precisely and to do that you need to know where the prostate is on a day-to-day basis,” he said. “Now that we can paint the dose wherever we want at practically any intensity that we want, the weakest link in the treatment chain is locating the target.”
The position of the prostate can vary as much as 2 centimeters in any one direction for a number of reasons, including changes in body weight, whether the bladder or rectum is empty or full, and organ motion due to respiration, cardiac and bowel motion, swallowing, and other movements while the patient is on the imaging table.
He disclosed that he had no relevant financial conflicts of interest to declare.
'Most patients will have multiple options regarding which treatment they wish to pursue.' DR. KUETTEL