The current standard of care for prostate cancer diagnosis typically involves an initial screening step principally utilizing serum blood testing — mainly total prostate-specific antigen (PSA) and others, such as free PSA, PSA isoforms — and a follow-up confirmatory test involving biopsy tissue sampling (systematic transrectal ultrasound guided biopsy) for pathologic evaluation. The trouble with this common strategy is that both steps are imprecise.
Serum blood testing, while useful, is well known to yield both false positive and false negative results. This has led to significant public health controversy, including some national guideline recommendations downgrading the value of initial screening in general. In addition, standard approaches to confirmatory biopsy using ultrasound guidance alone (TRUS biopsy) can result in considerable underestimation of the total amount of cancer in the prostate gland, including missed cancers of clinical significance. This is mainly due to the inability of ultrasound imaging to identify cancer within the gland — it can reliably identify the prostate anatomy but cannot distinguish cancer from benign conditions.
At SUNY Upstate Medical University, we strive to overcome these limitations to current methods of prostate cancer diagnosis. Utilizing imaging techniques developed at the National Cancer Institute, our radiologists utilize state of the art 3 Tesla multiparametric MRI — with endorectal coil, if necessary — to identify areas within the prostate gland which are likely to harbor cancer. Next, our urologists have implemented novel navigational biopsy equipment, UroNav MRI/US Fusion Biopsy System, which can utilize these MRI-based maps to guide the needle directly into the area of suspicion in an outpatient, office-based setting. This strategy allows us not only to minimize the possibly of missed cancers, but also gives us the best understanding of how much and how aggressive the cancer truly is within the prostate (see figure). This strategy has been demonstrated to have the greatest diagnostic power, with improved sensitivity and avoidance of over diagnosis. In this way, MRI-based approaches best allow significant cancers to be discovered, while tending to miss indolent lower risk cancers of minimal long term significance to the patient.
By implementing this new approach, we have been able to identify men who have otherwise had significant cancers which have been undetected using standard techniques. This allows for definitive therapy in situations of otherwise delayed diagnosis. More importantly, we are more confident that those men identified with low-risk cancers do not have hidden areas of higher risk disease. As a result, these men can be confidently followed with active surveillance without invasive treatments which are potentially harmful — especially to urinary function and sexual quality of life. In this way, our state of the art prostate cancer diagnostics are able to personalize the treatment plan for all men and avoid both over treatment and under treatment.
Figure legend:
This red triangle is an MRI-based 3-D image of the prostate in a man whose tumor was missed with standard biopsy approaches. The circular, colored areas are areas of suspicion, as indicated by a MRI scan. Using SUNY Upstate’s UroNav Fusion Biopsy System, we are able to hone in on areas where cancer may be hiding. The cylinders show where tissue samples were removed for biopsy. Significant cancer was found to occupy about a third of this man’s prostate, in the green circular region.
