PSA mass ratio shows prognostic power in localized prostate cancer

Research shows that pathologic prostate-specific antigen (PSA) mass ratio is a significant predictor for biochemical recurrence-free survival following radical prostatectomy for localized prostate cancer in patients with negative surgical resection margins.

“According to these results, it can be cautiously suggested that pathologic PSA mass ratio is a more sensitive predictor of [biochemical recurrence] after [radical prostatectomy] than serum PSA,” say authors Seok-Soo Byun (Seoul National University Bundang Hospital, Seongnam, Republic of Korea) and colleagues.

They analyzed data on 582 prostate cancer patients with pathologic tumor stage of 2 or less and negative surgical resection margins treated at their institution between 2003 and 2010.

The 5-year biochemical recurrence-free survival rate was 90.9%, and over a mean follow-up of 40.7 months, 4.1% of 341 patients with a PSA mass ratio of 0.40 µg/mL or less had biochemical recurrence compared with 9.5% of 241 patients with a greater PSA mass ratio.

The authors note that the latter patients also had several other unfavorable characteristics, including higher preoperative PSA concentration, larger tumor volume, smaller prostate volume, and worse Gleason score.

Nevertheless, on multivariate analysis, pathologic PSA mass ratio was associated with a 3.8-fold increased risk for biochemical recurrence. Additionally, Gleason score of 8 or more was associated with a 9.8-fold increased risk, whereas preoperative PSA level in itself was not associated with biochemical recurrence after multivariate adjustment.

Pathologic PSA mass ratio was the only significant prognostic factor in patients with a Gleason score of 7 or more, while no prognostic factor was significant in patients with lower Gleason scores. Pathologic PSA mass ratio was also not useful for predicting biochemical-free recurrence in patients with positive surgical resection margins, microscopic extraprostatic extension, or seminal vesicle invasion.

Writing in Urology, Byun and team suggest that PSA mass ratio has enhanced predictive power because it incorporates both PSA value and prostate volume, which they have previously shown to be associated with biochemical recurrence.

They say that it could help fulfill the “urgent need” for more accurate clinical predictors than serum PSA but add that “a large-scale, prospective, long-term study would be warranted to more precisely elucidate the association between pathologic PSA mass ratio and prostate cancer-specific survival.”

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