By: Dan Sperling, MD

“…the truth was discovered after my surgery, namely, that I had extracapsular extension.” JULES REICHEL

Prostate cancer (PCa) begins within the prostate gland. It is most successfully treated when the tumor is still contained in the gland. However, there are different cell lines, some of which multiply more quickly than others and tend to mutate into a more aggressive disease. If these tumors are not detected and diagnosed early, they have a higher probability of reaching the firm outer edge of the gland, called the capsule, and breaking through it. This is called extracapsular extension (extra means “beyond”, so the tumor has penetrated the capsule and begun growing outside of it). Historically, extracapsular extension (ECE) was rarely picked up by ultrasound imaging, or by transrectal ultrasound (TRUS) guided systematic biopsy. Rather, the probability of ECE was predicted by using nomograms based on clinical factors such as age, PSA and Gleason score drawn from large-scale population data. Without known evidence of ECE, many patients with both favorable and unfavorable clinical factors chose to be treated by radical prostatectomy, usually based on their doctors’ recommendations. Once the gland is removed and sent to pathology for examination, the discovery of ECE is not a pleasant revelation. “Compared with organ-confined disease, prostate cancer with extracapsular extension is associated with decreased overall and cancer-specific survival following radical prostatectomy.”^[iii] Patients found to have ECE are typically be sent for a course of beam radiation and/or be put on androgen deprivation therapy as a management strategy though it is not curative.

The ability to gain an accurate diagnosis of ECE would clearly assist patients and physicians in making appropriate treatment choices. In the early 2000s, articles on the use of MRI to detect ECE began to appear in medical journals. For example, in 2001 Thornbury et al. wrote, “To date, the primary goal of MR imaging for prostate cancer has been to detect extracapsular spread of tumor.”^[iv] Now, fourteen years later, multiparametric MRI (mpMRI) has evolved to the point where it is highly sensitive and specific at detecting ECE. Two recent articles illustrate this:

• In April 2015, Tom S. Feng, MD reported the results of his team’s investigation at Cedars-Sinai Medical Center (Los Angeles, CA).[iii] They identified 112 prostate cancer patients at their Center who underwent mpMRI followed by prostatectomy. They had two goals. First, they were exploring how well mpMRI identified established (local) ECE. Second they tested the ability of the same imaging to identify focal (lymph node) extension to five or fewer nodes outside the prostate. All images were read by a genitourinary radiologist with experience in prostate MRI, and his determinations were compared with the histopathology of the post-surgical gland specimens. Their findings confirm “the usefulness of multiparametric MRI for predicting extracapsular extension” in all prostate zones (though detection rates were lowest at the apex, and in the lymph nodes). Overall sensitivity was 70.7%, specificity was 90.6%, positive predictive value was 57.5%, and negative predictive value was 95.1%.

• In July 2015, Wibmer et al. from Memorial Sloan Kettering (New York, NY) demonstrated that the more specialized and experienced the reader, the more accurate the detection of ECE.^[v] MRI images of 76 patients were read and interpreted by a single radiologist for ECE before prostatectomy. Following surgery and histopathology results, the same images were read (in random order) by specialized genitourinary oncologic radiologists to obtain second opinions; 83% (71 out of 76) images were of diagnostic quality, so those 71 became the study population. The first- and second-opinion reports were then “unpaired and reviewed in random order by a urologist who was blinded to patients’ clinical details and histopathologic data.” The urologist found reporting disagreement in 30% of the cases, and when compared with the histopathology reports, the second opinions by the specialized readers were correct in 86% of the cases. Thus, expert readers increase the rates of correct diagnosis of ECE.

The practical ramifications of identifying ECE prior to treatment are very real for patients, especially those who are considering radical prostatectomy. Would someone choose to go through surgery knowing the odds are high of leaving PCa behind? Would that person be more likely to choose a course of radiation, hoping to destroy tumors that are extended into the prostate bed which the scalpel may not completely capture? These are tough decisions, but knowledge is power. The pretreatment information from mpMRI may be the determining factor, helping patients avoid the rigors of an aggressive surgical treatment when radiation may give them a better potential for cure.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

[i] Manceau C, Beauval JB, Lesourd M, Almeras C et al. MRI Characteristics Accurately Predict Biochemical
Recurrence after Radical Prostatectomy. J Clin Med. 2020 Nov 26;9(12):3841.
[ii] Wang JG, Huang BT, Huang L, Zhang X et al. Prediction of extracapsular extension in prostate cancer using the
Likert scale combined with clinical and pathological parameters.
[iii] http://www.hindawi.com/journals/pc/2011/485189/
[iv] http://radiopaedia.org/articles/extracapsular-extension-of-prostate-cancer
[v] Feng T, Afshar A, Smith S, Li Q, Shkolyar E et al. Assessment of multiparametric MRI for localizing site of extensive extracapsular extention of prostate cancer. Presented at the AUA Annual Meeting (Orlando, FL), May 16-21 2014.