Criteria for active surveillance of prostate cancer patients may miss unfavorable disease
MedWire News: Even the most stringent active surveillance (AS) selection models for men with prostate cancer may potentially result in disease misclassification and a risk for under-diagnosis, say French researchers.
AS protocols are used for patients with favorable disease characteristics such as a low Gleason score, pre-treatment prostate-specific antigen (PSA) level, and clinical stage, with the intention to introduce active treatment if there are signs of progression, explains the team.
“Our study demonstrates the limitations of AS inclusion criteria,” report Alexandre de la Taille and colleagues from the CHU Henri Mondor hospital in Creteil, France.
“The rate of unfavorable disease remains increased even with the use of the most selective criteria,” the team writes in The Journal of Urology.
They examined the rates of unfavorable disease found in the prostatectomy specimens of 468 prostate cancer patients who would have been eligible for AS according to any of three sets of biopsy inclusion criteria.
Rates of biochemical disease-free survival were also calculated, with failure defined as a PSA greater than 0.2 ng/ml after RP.
Group 1 (n=89) criteria for AS stipulated fewer than three positive cores and less than 3 mm total tumor length, group 2 (n=112) stipulated fewer than three positive cores with cancer involvement of less than 50% in any core, and group 3 (n=177) required tumor to involve less than 33% of any positive cores.
After RP, the majority (51.7%) of group 1 patients had Gleason score 6 disease, while in groups 2 and 3, the majority had Gleason 7 or greater (53.6% and 55.4%, respectively), indicating unfavorable disease.
Additional unfavorable characteristics varied among AS groups, including 17.5% extracapsular extension among specimens in group 2 compared with 11.2% in group 1. Rates of positive surgical margins were 20.9% in group 3 compared with 18.0 in group 1.
The risk for overall unfavorable disease (T3–4 and/or Gleason score 8 or more) was significantly higher in men with cancer involvement of 3 mm or greater at biopsy
At 3 years after RP, the researchers report an overall biochemical disease-free survival of 94.0%, which did not differ between the three AS definitions.
“Any AS selective model has the potential limitations of a risk of under-diagnosis, adverse pathological findings and the potential hazards of missing the window of curability,” conclude de la Taille et al.
In an accompanying editorial, Nazareno Suardi (Vita-Salute University San Raffaele, Milan, Italy) commented: “As long as definitive long-term cancer specific outcomes are not available, the misclassification issue will represent the major concern in the AS approach to patients with low risk prostate cancer.”
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By Sarah Guy