Clinical stage not predictive for prostate cancer recurrence

Reese AC. Cancer. 2010;doi:10.1002/cncr.25596.

Clinical stage does not predict recurrence after prostatectomy, according to results of an analysis of the CaPSURE database.

Researchers said more than 35% of patients are staged incorrectly, but there was no association between stage and likelihood of recurrence after correcting for staging.

Researchers analyzed all patients with localized clinical T1 and clinical T2 prostate adenocarcinoma entered into Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) database (n=3,875) from 1995 to 2008. CaPSURE is a national registry of men treated at 40 academic and community-based urology practices across the United States. The database includes records on demographics, quality of life and resource-use variables, which have been recorded prospectively since 1997. Data for men diagnosed before 1997 were recorded retrospectively.

Data from digital rectal examinations and transrectal ultrasound are included in CaPSURE, as well as lesion laterality and the presence or absence of a palpable nodule on digital rectal exam or visible lesion on transrectal ultrasound.

Assigned clinical stage was defined as the clinical T stage reported directly to the database managers from the participating clinicians based on each practitioner’s interpretation of the clinical staging criteria.

Researchers did not find an association between advanced clinical T2 stage and risk for biochemical disease recurrence. In contrast, there was a strong association between risk for disease recurrence and increasing PSA level, advanced biopsy Gleason score and percentage of positive biopsies of more than 33%.

Researchers found that 35.4% of men were incorrectly staged. Most men, 55.1%, were incorrectly downstaged while the remainder were staged inappropriately high. The researchers said most staging errors were caused by physicians ignoring ultrasound results and inappropriate consideration of biopsy results when assigning clinical stage.

With both exams, men with abnormal results were more likely to be incorrectly staged. Of men with normal results on either test, only 8.6% were incorrectly staged. More than half of the men with abnormal results, 51.9%, were staged incorrectly.

Men with abnormalities discovered through ultrasound were more likely to be incorrectly staged than those who underwent digital rectal exam, 65.8% vs. 38.2%.

Researchers found that biopsy laterality was a better predictor of assigned clinical stage than findings from digital rectal exam or ultrasound. A patient’s odds of being staged with clinical T2a/b were 2.5 times greater (95% CI, 2.0-3.1) for those who had unilaterally positive biopsies compared with patients who underwent unilateral digital rectal exam or transrectal ultrasound findings. Similarly, patients with bilaterally positive biopsies were 1.2 times more likely (95% CI, 1.1-1.3) to be staged as having clinical T2 tumors.

This is an interesting academic question, but it doesn't have a lot of clinical value or benefit given the presentation of most men with prostate cancer today. I think the results prove the hypothesis: Clinical staging for many men at presentation is inaccurate, and this is probably because the difference between stage I and stage II prostate cancer is likely clinically insignificant, and these stages comprise the great majority of patients when they are diagnosed. The challenge is that clinical staging doesn't make that much difference for the majority of these patients who have stage I or II prostate cancer. It may be inaccurate, but the reality for most men with prostate cancer today is that clinical stage is a somewhat minor detail because it doesn't impact upon what kind of therapy they can have, and furthermore, the accuracy of the initial clinical staging has no real impact on the success of subsequent therapy.

What this study shows is that for most men with prostate cancer who commonly present with either stage I or II disease, because the difference between stage I and stage II is so minor, clinical staging — whether accurate or not — doesn't make any difference for them. Many patients, and this is true of the cohort of men in the study, if they go on to surgery, they then will have pathologically staged disease. In general, the pathological stage is far more accurate because it is objective; the pathology data is also much more predictive of outcome and falls in line with what we hope to achieve with staging. For this group of men, especially following surgery, whether or not their clinical staging was correct probably doesn't have any real impact because they subsequently have surgery results, whose information will trump the importance of the pre-treatment clinical staging.

– David YT Chen, MD
Associate Professor, Urologic Oncology,
Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia

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