Risk factor stratification indicates outcome in prostate surveillance patients
MedWire News: Risk factor stratification, incorporating clinical factors available at diagnostic and follow-up biopsies, can indicate the likelihood of disease progression in prostate cancer patients treated with active surveillance (AS), say researchers.
The team reports a "considerable improvement in the estimated progression rate" among AS patients when factors such as prostate-specific antigen (PSA) density, family history, and PSA velocity are taken into account.
"Patients with very low-risk (insignificant) and low-risk prostate cancer are candidates for AS with the objective of avoiding treatment for small and indolent cancers that may never result in the risk of death," note William DeWolf (Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA) and co-workers.
"However, the important question arises of whether patients with clinically insignificant disease can be identified with reasonable accuracy," they add, in the Journal of Urology.
The team assessed risk stratification in a cohort of 120 low-risk prostate cancer patients treated with AS who underwent at least one re-biopsy after their initial diagnostic biopsy. The men were also followed-up with PSA examinations every 6 months.
After a median follow-up of 2.4 years, 36 (30%) men experienced progression, defined as having 3 or more positive cores at follow-up biopsy, increased Gleason score (7 or greater), and/or more than 50% cancer involvement in any one biopsy core.
Multivariate analysis, involving only clinical and pathological variables available at diagnosis biopsy, showed that having a PSA density above rather than below the median (0.08 ng/ml/cm3), and having a family history compared with not having a family history of prostate cancer predicted the likelihood of disease progression, with hazard ratios of 2.66 and 1.93, respectively.
Furthermore, having both of these variables increased the risk for disease progression 5.10-fold compared with not having either.
A second multivariate analysis that included PSA velocity revealed that men with more rapidly increasing PSA levels (0.11-16.33 ng/ml/year) between initial and follow-up biopsy were 2.82 times more likely to progress, compared with men whose PSA levels increased less dramatically (-12.17-0.10 ng/ml/year).
Patients with the highest risk score - with all three predictive variables from both analyses - were the most likely to experience disease progression, with a hazard ratio of 19.49 compared with men who had none of these factors.
Finally, having a PSA density of 0.08 ng/ml/cm3 or higher, versus lower, at first biopsy was validated as a significant predictor of subsequent progression (hazard ratio 3.16), conclude DeWolf et al.
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By Sarah Guy