The University of California, San Francisco (UCSF) Cancer of the Prostate Risk Assessment (CAPRA) score was initially introduced in 2005 and validated in 2006 as a pre-treatment tool that could be used to assess risk for prostate cancer recurrence after first-line treatment. We have previously described the use of the CAPRA scoring system, and the fact that at UCSF it is now being used to assess patients who may be suitable for management under active surveillance.
In a new paper, Cooperberg et al. have described a comparable post-surgical tool to be known as the CAPRA-S (the Cancer of the Prostate Risk Assessment Post-Surgical) score, which can also be used to project risk of prostate cancer recurrence after first-line surgery.
In a manner similar to the original CAPRA score, the CAPRA-S score is a number from 1 to 12 that is calculated for each individual patient. However, the CAPRA-S score is based on data available before and after the surgical excision of the prostate:
- The pre-surgical PSA level
- The pathologic Gleason score
- The presence or absence of positive surgical margins
- Whether there was extracapsular extension
- Whether cancer extended into the seminal vesicles
- Whether cancer extended into the regional lymph nodes
The following table provides the data necessary for an individual patient to be able to assess his CAPRA-S score:
Use of the CAPRA-S scores was correlated to actual biochemical recurrence data for > 3,800 radical prostatectomy patients in the CAPSURE database treated after 1992, of whom 644 had subsequent disease recurrence. The model allows for the following predictive output at 3 and at 5 years after surgery:
Let’s look at a couple of examples:
- JRK is 58 years of age. He had a robot-assisted laparoscopic prostatectomy (RALP) in May this year. His PSA pre-surgery was 6.4 ng/ml. After surgery, his pathologic Gleason score was 3 + 3 = 6; he had a positive surgical margin; and he had no sign of extracapsular disease or extension of the cancer into his seminal vesicles or his lymph nodes. We can calculate his CAPRA-S score as 1 + 0 + 2 + 0 + 0 + 0 = 3. This gives him a probability of biochemical progression-free survival of about 70 percent at 5 years.
- ASR is also 64 years old and had an open radical prostatectomy in May. Before surgery, his PSA was 3.8 ng/ml. After surgery his pathologic Gleason score was also 3 + 3 = 6; he had negative surgical margins, but (unusually for someone with a Gleason score of 6) he did have cancer that was evident in one of his seminal vesicles. We can calculate ASR’s CAPRA-S score as 0 + 0 + 0 + 0 + 2 + 0 = 2. This gives a probability of biochemical progression-free survival of about 83 percent at 5 years.
Cooperberg et al. note carefully that “the CAPRA-S score is meant to be used primarily as a measure of relative risk” of biochemical progression. They further state that, “Additional validations studies will be required to determine how consistently the absolute risk predictions are calibrated across different clinical contexts.”
It is important to note that the CAPRA-S projections are based on data from a wide spectrum of data from community-based urologists (as compared to data from the Kattan nomograms, which are based on experience from a high-volume, high-skill academic setting). It will be interesting to see whether the CAPRA-S score projections can be validated using data sets such as the SEARCH database, which has been developed from experience in a group of VA medical centers. We understand that such a validation study is ongoing.