August 2, 2010
Delay unlikely to worsen tumors for low-risk prostate cancer
Johns Hopkins experts have found that men enrolled in an active surveillance program for prostate cancer who eventually needed surgery to remove their prostates fared just as well as men who opted to remove the gland immediately, except if a follow-up biopsy during surveillance showed high-grade cancer.
The findings were presented at the American Society of Clinical Oncology meeting held in June in Chicago.
Active surveillance, or “watchful waiting,” is an option open to men whose tumors are considered small, low-grade and at low risk of being lethal. Given the potential complications of prostate surgery and the likelihood that certain low-risk tumors do not require treatment, some men opt to enroll in active surveillance programs to monitor PSA levels and receive annual biopsies to detect cellular changes that signal a higher grade, more aggressive cancer for which treatment is recommended; yet, according to the Johns Hopkins experts, there is concern that delaying surgery in this group until biopsy results worsen may result in cancers that are more lethal and difficult to cure.
Bruce Trock, associate professor at the Johns Hopkins Brady Urological Institute, and his colleagues compared the pathology results of men in an active surveillance group at Johns Hopkins who later had surgery with those who also had low-risk tumors and opted for immediate surgery.
Results initially showed that 116 active surveillance participants who had surgery were more likely to have high-grade, larger tumors than 348 men who had immediate surgery. But Trock says that these results were found in only 43 (37 percent) men in the surveillance group who were recommended for surgery because a follow-up biopsy during surveillance worsened to indicate a high-grade tumor.
“We think that these men had high-grade tumors to begin with that their initial biopsy missed, and this group may be overrepresented in men who are recommended for treatment after an initial period of active surveillance,” Trock says. He adds that, in general, 15 percent to 25 percent of men whose initial biopsy shows a low-risk prostate tumor will actually have a high-grade cancer upon further review of the entire prostate once it is removed.
Apart from the 43 men whose pathology results worsened during surveillance, the remaining men in the surveillance group had pathology results at surgery similar to those in the immediate surgery group. “This means that most tumors are not likely to worsen during the period of active surveillance,” Trock says.
The researchers calculate that the risk of finding high-grade tumors in the entire group of 801 active surveillance patients is low, at about 4.5 percent per year.
Trock is leading a National Cancer Institute–funded study with four other cancer centers to find biomarkers that may identify men who have worse tumors than their initial biopsy indicates.
The Johns Hopkins Active Surveillance program, led by H. Ballentine Carter, a professor of urology, has enrolled 801 men since 1995 and is believed to be the largest such program in the United States. Fourteen men in the program who later had radiation and four who had radical prostatectomy developed recurrences, but no participants have developed distant metastases and none have died from prostate cancer. Fourteen men in the program died from causes unrelated to prostate cancer.
The current study was funded by the Johns Hopkins Prostate Cancer Specialized Program of Research Excellence (SPORE) grant awarded by the National Cancer Institute and by Dr. and Mrs. Peter S. Bing. The research also was presented at the American Urological Association Annual Meeting.