By: Dan Sperling, MD

Until fairly recently, when a man was suspected of having prostate cancer based on his PSA, the standard protocol has been to send him for a transrectal ultrasound-guided (TRUS) biopsy. The journal European Urology carried an article in December, 2013 that consisted of a literature review of both TRUS biopsies and template-guided transperineal biopsies.[i] The authors’ purpose was a survey across a broad article database to identify the most common side effects of these approaches to prostate biopsy. Given the current dialogue—at times, controversy—over the costs and benefits of PSA screening leading to over-biopsy and over-treatment, it is important to understand to what extent conventional biopsies put patients at risk and burden the healthcare system.

The authors searched for articles containing data on the following biopsy complications: hematuria (blood in urine), rectal bleeding, hematospermia (blood in semen), infection, pain, lower urinary tract symptoms, urinary retention, erectile dysfunction, and mortality. They found that blood in urine and semen were common but usually not severe, and tended to clear up. Likewise, rectal bleeding was rarely severe. Complications from infection were the most common reason for hospitalization after biopsy, even though antibiotics were routinely given before biopsy; of concern is that the rate of these complications appears to be rising and the severity can increase unless promptly dealt with. Pain is reported at several stages of biopsy, but anesthetic agents and anxiety-reducing techniques should be used to lessen or eliminate pain. Up to 25% of men have transient lower urinary tract symptoms; less than 2% of men go into urinary retention (unable to urinate). Death related to biopsy is rare.

To address the rates of infection, the authors recommend the administration of antimicrobial agents that are effective against antibiotic-resistant bacteria. They also point out that pain should be alleviated and there are various ways to do so. Thus, from preparation to aftermath, random needle biopsies are gradually being replaced by a new standard of care: use imaging as a precursor to biopsy, and if needed, use image-based targeted biopsies.

MRI is superior to other imaging modalities in revealing the location, size and shape of suspicious areas. An article by Hoeks et al[ii] states that “…multiparametric MR imaging of the prostate has shown promising results and may be of additional value in prostate cancer localization and local staging.” As journal articles on prostate MRI appear with greater frequency, radiologists are formulating standards of technical requirements, clinical indications and interpretation to work toward consistent protocols and implementation. In all cases, according to the authors, “Education and experience of specialist radiologists are essential for correct interpretation of multiparametric prostate MR imaging findings.”

An interesting study on prostate 3T MRI results compared with TRUS biopsy findings was published last year by a team from the Czech republic.[iii] This type of clinical study is essential in order to determine if the imaging findings in fact correlate with tissue samples.

This study recruited 191 patients suspected of having prostate cancer due to elevated PSA. The patients were informed that they would first undergo MRI followed by transrectal biopsy. The parameters include T2-weighted images, diffusion weighted images, MR spectroscopy and the pharmacokinetic evaluation of the data obtained during the dynamic post-contrast T1 imaging (an assessment that can reveal abnormal blood flow due to a tumor’s blood supply). At least three positive MRI findings were considered to indicate the presence of prostate cancer. 27 of the patients were subsequently excluded from biopsy based on imaging lack or low probability of cancer. The other 164 patients had TRUS biopsy based on locations revealed by the MRI. All biopsies were evaluated by a specialist in uropathology, and 84 malignant tumors were identified.

Based on the comparison of the image interpretations and the tissue samples, the 3T MRI achieved a 97.6% sensitivity (positive identification of cancer) and 85% specificity (areas correctly identified as not being cancerous). There were only three false negative findings (areas interpreted as not having cancer but found to be cancerous by biopsy).

In conclusion, the authors wrote, “The implementation of 3T MRI in routine assessment of patients with elevated PSA should preclude the number of biopsies performed and improve the number the tumors detected due to better targeted biopsies.” This calls to mind the guiding medical principle of “Above all, do no harm.” In the face of many possible kinds and degrees of TRUS biopsy side effects, this study and others make a compelling case for establishing a new standard of diagnostic care in prostate cancer: first, use advanced 3T multiparametric MRI to reveal areas of suspicion; second, target biopsies into those regions. In this way, clinicians can offer patients selective, precise diagnostic procedures and avoid undue risk of harm.