There are so many benefits to detecting prostate cancer (PCa) using multiparametric MRI that it’s hard to single out just one. However, the merits of mpMRI to find PCa in large glands deserve a spotlight.
First, a word about prostate size. An average adult gland in younger men is about 30 – 40cc, roughly the size of a walnut or golf ball. The prostate has three zones: central, transition and peripheral. With aging, it is normal for the gland to enlarge as cells in the transition zone begin to proliferate. This is called benign prostate hyperplasia (BPH), meaning the cells are progressing abnormally (hyperplasia) but it’s not cancer. Thus, many aging men have glands that slowly enlarge decade by decade. Statistically, half of men age 50 have BPH or an enlarged prostate, 65% of men between the ages of 60 and 70 have it, and by 80 years approximately 80% of men are affected by BPH. Glands less than 50cc are considered normal, 50-80cc is midsize, and larger than 80cc is large. Interestingly, there is a positive correlation between larger glands and higher PSA values. For older men, a rise in PSA is more likely to mean BPH than PCa. This is good reason to not panic if PSA screening returns a higher number than 4.0 ng/mL.
However, if a man with a gland bigger than 80cc has an unusually high PSA, it’s not unreasonable to suspect prostate cancer. The problem is that standard 12-core TRUS biopsy misses PCa more frequently in large glands than in normal glands.[i] It is like trying to find the proverbial needle in a bigger haystack. A proposed solution is to increase to 14, 18 or even 20 cores, but this raises the chance of biopsy-related infection and side effects (rectal bleeding, blood in urine or semen, and urinary or sexual problems).
Today, it is becoming a standard of care to offer pre-biopsy mpMRI to patients who already had at least one negative biopsy. The principle is to avoid putting a patient through another biopsy until there is visual evidence of suspected significant PCa. Indeed, real-time MRI targeted biopsies outperform repeat TRUS biopsies in detecting cancer that was previously missed. The Sperling Prostate Center firmly believes it is in the best interest of all men at any stage of suspicion to have mpMRI before biopsy, but there is one group that can benefit greatly by mpMRI before a 1st biopsy – those with large glands.
It makes no sense to blindly and randomly aim biopsy needles into the gland when the probability of hitting significant PCa is the lowest for this group of patients. The advantage of mpMRI is identifying exactly where to aim needles during an in-bore biopsy, for the greatest detection and diagnostic accuracy. Peltier et al. (2016) clearly showed that for men with large glands, the detection rate for clinically significant PCa was higher when using the MRI targeted approach compared to standard biopsy.[ii] And, if the pre-biopsy mpMRI is negative for significant PCa, the patient can continue to be monitored by periodic PSA blood tests with mpMRI as needed.
Large prostate glands are primarily the result of BPH, and for those whose BPH creates bothersome urinary symptoms, we can evaluate your BPH to see if our Focal Laser Ablation can alleviate your symptoms by reducing BPH volume. In addition, a large gland can harbor prostatitis and even prostate cancer that is difficult to detect and diagnose. Our advanced multiparametric MRI and our expert interpreters can reveal what’s going on. The Sperling Prostate Center invites men who are concerned about their gland size and PSA results to contact us for information on how we can be of service before you go for a prostate biopsy.
[i] Serefoglu E, Altinaova S, Ugras N, Akincioglu E et al. How reliable is 12-core prostate biopsy procedure in the detection of prostate cancer? Can Urol Assoc J. 2013 May-Jun; 7(5-6): E293–E298.
[ii] Peltier A, Aoun F, Albisinni S, Marcelis Q, Ledinh D, Paesmans M, Lemort M, van Velthoven R. Results of a comparative analysis of magnetic resonance imaging-targeted versus three-dimensional transrectal ultrasound prostate biopsies: Size does matter. Scand J Urol. 2016 Jun;50(3):144-8