At the Genitourinary Cancers Symposium, held March 5-7 in San Francisco, researchers presented a study that showed men with early-stage prostate cancer can benefit from a combination of hormonal therapy and radiation therapy.
Knowing that not all men are at the same risk for recurrence, investigators of the phase 3 RTOG 94-08 study analyzed the results after stratifying nearly 2,000 men as being low-, intermediate-, or high-risk for recurrence. They found that men with intermediate risk who received short-term total androgen suppression and radiation lived longer than men with similar risk who received radiation only. Intermediate risk was defined as having a Gleason score of 7, or a score of 6 or less with either a PSA between 10 and 20 or a staging subcategory of T2b (where cancer is present in 50 percent of one lobe of the prostate gland). Intermediate-risk patients in the combination arm received a total of four months of hormonal therapy, with radiation therapy beginning after two months. After two years, a repeat biopsy was performed in 843 men to gauge recurrence--of 439 men who received the combination therapy, 78 percent had no sign of a recurrence; in the 404 men who received just radiation, only 60 percent had no evidence of cancer. After 12 years of follow-up, 51 percent of intermediate-risk patients in the combination group were alive compared with 46 percent in the radiation-alone group. Researchers noted that previous studies show that men at high-risk should receive more than four months of hormonal therapy, so there was more focus on the results for intermediate-risk patients.Researchers also found that men with low-risk disease did not benefit from the combination, which highlights another interesting point about the new way we're studying medicine. If all of the patients receiving the combination had been lumped into just one group, the results would have not been as dramatic. It might also have driven some men to undergo the cost, side effects, and inconvenience of a therapy that would ultimately have had no benefit for them. Continuing to analyze subgroups in trials such as these will show us how best to use certain therapies for certain patients. The benefit of the combination in intermediate-risk patients could be even greater than what the study initially suggests. While researchers designed the study using radiation therapy that was standard in 1994, the field has seen many advances since then, such as being able to provide higher, more targeted--and albeit, safer--doses. A new trial called RTOG 0815 will be studying men with intermediate-risk, early-stage prostate cancer, but using 3-dimensional conformal radiation therapy or intensity-modulated radiation therapy with androgen deprivation therapy to see if the benefit of the combination still exists. (You can read more about these radiation techniques in "Targeted Strike.") Details of the RTOG 0815 clinical trial can be found at clinicaltrials.gov.