Urologic oncology 2016-09
Endorectal MRI for risk classification of localized prostate cancer: Radiographic findings and influence on treatment decisions.
Abstract
Purpose
To report the results of endorectal coil magnetic resonance imaging (eMRI) in patients with localized prostate cancer, and how these images influenced radiotherapeutic management.
Materials and methods
A total of 122 men with localized adenocarcinoma of the prostate referred to radiation oncology underwent 3-T eMRI between 2010 and 2014, to evaluate candidacy for active surveillance (n = 26) and brachytherapy as monotherapy (n = 47), or to further risk stratify intermediate-risk (n = 29) or high-risk (n = 20) men before external beam radiation therapy. By National Comprehensive Cancer Network classification, men had low-risk (28%), intermediate-risk (55%), or high-risk (17%) disease. Multiparametric MRI sequences included T2-weighted, diffusion-weighted imaging, and dynamic contrast-enhanced imaging. Radiographic extracapsular extension, seminal vesicle invasion (rSVI), and pelvic lymph node involvement (LNI) were graded as negative, indeterminate, or positive. A dominant nodule was defined as a nodule≥1.5cm. Changes in management were identified comparing pre-MRI and post-MRI plan of care.
Results
The rates of radiographic extracapsular extension, radiographic seminal vesicle invasion, lymph node involvement, and dominant nodule were 39%, 7%, 12%, and 28%, respectively. The eMRI identified measurable disease in most patients with an increasing burden of disease (sextants involved, median nodule size) according to risk category (P<0.01). Changes in management after eMRI occurred in 18%, including 9%, 18%, and 33% of men with low-risk, intermediate-risk, or high-risk disease (P = 0.08), and 12%, 17%, and 22% of men who were candidates for active surveillance, brachytherapy as monotherapy, or external beam radiation therapy (P = 0.48), respectively.
Conclusion
The eMRI influenced management in a risk-dependent fashion. Further study is required to determine the clinical importance of eMRI findings and to determine whether changes in management can lead to improved clinical outcome.
Related Questions
When should multiparametric MRI (mpMRI) be utilized in prostate cancer workup?
Early adopters of prostate mpMRI are unique and always a pleasure to meet. I've learned a great deal from many of them. They’ve moved beyond aiming at a CT density in the pelvis and learned how to use mpMRI sequences to better classify the risk of disease they’re treating. This is in comparison to o...
Would you treat a patient with prostate biopsy (and or MRI) suspicious for extraprostatic extension as high risk if they otherwise have IR disease factors?
Men in the intermediate risk category are a heterogeneous group, and clinical factors can be a useful way to further stratify risk in this group. In our practice, because of an institutional outcomes study, we primarily use % positive cores > 50% as a means to select men for the more aggressive ther...