A new Fox Chase Cancer Center study suggests a biopsy reveals more important information about a man's prostate cancer than previously understood. Doctors hope the new findings will help them tailor radiation treatment.
"Radiotherapy offers the chance of a cure for most patients," explained Mark K. Buyyounouski, M.D., M.S., attending physician in the radiation oncology department at Fox Chase Cancer Center. "For some, however, an elevated PSA level after treatment indicates the cancer is still around or has come back. Our new study shows how we can use biopsy information prior to treatment to help us predict which patients are most likely to still have disease after treatment. With this knowledge, we can better tailor treatment."
In the study presented by Buyyounouski today at the 2008 Genitourinary Cancers Symposium in San Francisco, researchers compared prostate biopsies taken before treatment with those taken again two years after treatment. All the study volunteers had cancers that were classified as intermediate or high risk.
"Larger tumors are believed to be more likely to persist after treatment, but what defines a larger tumor has been controversial," said Buyyounouski. "What we found was that a high percentage of cancer observed in the biopsy taken before treatment correlated with a higher probability of a positive biopsy after treatment. This information is important because locally persistent prostate cancer may result in laterspread of the disease and possibly death."
Buyyounouski explained that other researchers have explored the use of biopsy information to identify higher risk of recurrence for men with prostate cancer. Using a percentage of positive biopsy cores has been advocated by some, but these types of studies compared the cores to PSA level after treatment and not post-treatment biopsies.
"This study is important because the percentage of cancer seen in the biopsy before treatment is directly correlated with cancer seen in the biopsy in the same location two years after treatment," explained Buyyounouski.
"We believe this study will help raise awareness about which patients may be at greatest risk of having persistent prostate cancer and help us improve future treatment."
Buyyounouski said current sophisticated radiation technologies such as IMRT could allow physicians to tailor treatment for these patients. "Our next step in this area of research is to see if we can prevent recurrence by delivering more radiation to the area of the prostate with the greatest amount of cancer."
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