What is the role of biopsy in the workup of prostate cancer?

Updated: Jan 15, 2019
  • Author: Lanna Cheuck, DO; Chief Editor: Edward David Kim, MD, FACS  more...
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Answer

Physical examination findings alone cannot reliably differentiate a cyst or calculus from cancer foci. Therefore, a biopsy is warranted in these circumstances, to aid in the diagnosis and to determine the Gleason score.

Before the biopsy, antibiotics are administered and an enema is often provided, with a short course of antibiotics administered after the biopsy as well. Coagulation tests are not routinely performed, but patients are instructed to stop aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) 10 days prior to the biopsy. Many, but not all, physicians use lidocaine prior to the biopsy.

The number of biopsy specimens that should be obtained is debated. Sextant- versus 12- versus 18-core biopsy protocols are published in the literature. The 12- or 18-core protocols yield more specimens from the lateral regions and usually sample the transition zone. Several studies have demonstrated an increase in the cancer detection rate, but others have not. The NCCN recommends extended-pattern biopsy with six sextant cores and six cores from the lateral peripheral zone, along with lesion-directed sampling of palpable nodules and sites corresponding to suspicious images. [3]

In men with a negative biopsy result, epigenetic profiling with the ConfirmMDx assay (MDxHealth, Irvine, CA) may help to distinguish patients who have a true negative biopsy from those at risk for occult cancer. ConfirmMDx is a commercially available assay that assesses methylation markers of prostate cancer (GSTP1, APC, and RASSF1) to distinguish histologically benign biopsy cores from patients diagnosed with no cancer, low-volume cancer (Gleason score 6), or higher-volume cancer (Gleason score 7). The assay has a negative predictive value of 90%, but a positive predictive value of only 28%. [18]

PCA3 is a prostate-specific, non-coding messenger RNA biomarker that is detectable in urine sediments obtained after three strokes of prostatic massage during DRE. A urine test for PCA3 (Progensa PCA3) is commercially available. Currently, the main indication for PCA3 testing is to help determine whether repeat biopsy is needed after an initially negative biopsy. A negative result, considered together with clinical and other laboratory information, would argue against repeat biopsy. [17]


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