Prostate cancer patients receiving increased radiation doses delivered by highly conformal external beam radiation had a greater disease-free survival rate, according to a study presented October 5 at the American Society for Therapeutic Radiology and Oncology’s annual meeting in Atlanta.
For two decades, external beam radiation therapy has been one of the standard methods for treating prostate cancer. In the past, radiation oncologists have been limited in terms of the dose they could deliver to the affected area for fear of inducing serious bladder or rectal side effects.
In recent years, however, external radiation has become much more accurate, while the delivery of higher doses of radiation has become a real possibility.
Researchers examined whether a highly conformal technique employing the proton beam would allow the safe delivery of high radiation doses and whether the higher radiation doses would make a difference in the treatment of early stage prostate cancer.
The study involved 393 men with early stage prostate cancer who received either conventional dose or high-dose radiation therapy.
Regardless of the dosage, all of the patients were treated with the more accurate conformal radiation that included the use of a proton beam.
The five-year disease-free survival rate for those who received high-dose radiation therapy was promising as only 17 percent showed evidence of a recurrence of their cancer. Thirty-five percent of the patients who received the conventional dose experienced recurrence of cancer.
The level of rectal and bladder side effects was equally low – less than 2 percent experienced serious problems – whether the patients were treated with conventional dose or high-dose radiation.
“This study suggests that radiation oncologists can and should be more aggressive in their treatment of prostate cancer provided they have sophisticated dose delivery techniques such as proton beam at their disposal,” said study author Anthony Zietman, M.D., a radiation oncologist at Massachusetts General Hospital in Boston.
