A new report based on data from the cohort of patients being managed with active surveillance (AS) at the University of California, San Francisco, has emphasized the potential importance of repeat biopsies in the care and treatment of these men.
Whitson et al. have published data on a total of 241 men within the complete UCSF AS cohort who met certain very specific study criteria:
- Prospective enrollment in the UCSF AS study cohort
- At time of diagnosis, PSA < 10 ng/ml, clinical stage T1/2, Gleason score ≤ 6, ≤ 33 percent of at least six biopsy cores positive for cancer, no more than 50 percent of any single core positive for cancer
- At least two PSA measurements during the interval from 1 year before diagnostic biopsy to the data of a first repeat biopsy
- No repeat biopsy within 3 months of the initial diagnostic biopsy
- At least one repeat biopsy between 3 and 24 months after the initial diagnostic biopsy
The researchers identified 241 out of 408 patients who met the eligibility criteria for this analysis. Based on the analysis of the data from these 241 patients, they were able to show the following:
- Average (mean) age of the patients was 61 ± 7 years.
- Their average (mean) PSA level at study enrollment was 4.9 ± 2.2 ng/ml.
- The median time to repeat biopsy after initial diagnosis was 10 months.
- Biopsy-based disease progression occurred in 56/241 men (23 percent).
- 46/241 (19 percent) had a Gleason score upgrade.
- 11/241 (5 percent) had biopsy cores > 33 percent positive for cancer.
- 12/241 (5 percent) had a single biopsy core > 50 percent positive for cancer.
- 1/241 men had a PSA value that doubled during the study period of 3 years.
- 7/241 men had PSA values that had halved during the study period of 3 years.
Whitson et al. conclude that, in their series of well-staged, low-risk prostate cancer patients on active surveillance, “There is little change” in the PSA levels during the first 2 years of surveillance, but there is still a significant percentage of men who can be shown to have disease progression on repeat biopsy.
This is a reasonable conclusion based on this series of men. However, it is notable that the men entering the UCSF protocol are not all given a standardized, 12-core biopsy at the time of study entry (as practiced and recommended by other centers, such as Memorial Sloan-Kettering Cancer Center). Indeed, man who did receive a confirmatory “diagnostic” biopsy within 3 months of their initial diagnostic biopsy were specifically excluded from the current analysis.
One cannot help but wonder whether, if all the UCSF patients were also given such a standardized, 12-core biopsy before being enrolled into the study protocol, a significant number of the 56 patients who were shown to have progression on a repeat biopsy might have been ruled ineligible for trial entry in the first place.
The “New” Prostate Cancer InfoLink thinks that this study helps to demonstrate the importance of standardizing entry criteria for long-term studies of active surveillance to ensure that we are comparing apples to apples when we see data from apparently similar studies carried out a different centers. It also clearly shows that when patients do not receive a standardized, confirmatory, 12-core prostate biopsy before enrollment into an active surveillance protocol, at least one repeat biopsy within 24 months of the initial diagnostic biopsy is almost certainly essential (regardless of any changes in the patients’ PSA levels).