Underdiagnosis More of a Problem In Prostate Cancer Than Overdiagnosis

Categories: Winter 2006

A small but vocal group of physicians is saying that prostate cancer screening has resulted in overdiagnosis and therefore overtreatment of prostate cancers.

The reality is that prostate cancer screening is doing considerably more good than harm. (Catalona and Graif, 2006)

Since prostate cancer diagnosis using the PSA test (called the PSA era), we’ve seen a 32.5% decrease in death rates from prostate cancer and a 75% decrease in metastic cancer (that has spread beyond the prostate) at time of diagnosis.

When our study group used PSA of 4 ng/mL as the biopsy threshold, 30% of the men had cancers with advanced pathology features and 1.3% had features that would indicate they might be overdiagnosed.

In the screening group using a PSA 2.5 ng/mL as the biopsy threshold (the cutoff we’ve been using since 1995), 7% of the men could be considered *overdiagnosed and 26% were **uderdiagnosed.

Another finding was that lowering the PSA threshold for biopsy from 4 to 2.5 resulted in an overall 4% decrease I the rate of underdiagnosis and a corresponding 7% increase in 5-year progression-free survival.

Clearly, 2.5 is a better PSA threshold for recommending a biopsy.

*overdiagnosed (Ohori): a cancer volume less than 0.5cc’s, organ-confined, and no Gleason pattern o 4 or 5 (Note: I feel it is impossible to predict that an individual cancer is insignificant in any given patient, particularly a young patient, because tumors can develop mutations and become more aggressive over time.)

**underdiagnosed (Catalona): at radical prostatectomy found to have advanced pathology features including: tumor outside the prostate, positive surgical margins,or lymph node metastases

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