Updated on primary prostate cancer imaging

(UroToday.com) At the Society of Urologic Oncology (SUO) annual meeting, Dr. James Wysock provided an update on imaging for primary prostate cancer. Dr. Wysock briefly touched on imaging strategies in both screening and diagnosing localized prostate cancer.

Poor sensitivity and specificity in screening and diagnosing men with prostate cancer is a well known limitation of our current technologies. Prostate specific antigen (PSA0 direct screening and transrectal ultrasound guided biopsies (TRUS) lead to both clinically significant prostate cancer undersampling and excessive detection of indolent prostate cancer. As a result, there was a growing interest in the use of MRI and MRI-targeted biopsies to aid in this diagnostic gap Dr. Wysock presents data from Kim et al. demonstrating the rapid increase in prostate MRI use in recent years, reflecting this increasing dependence on magnetic resonance-guided biopsies (Figure 1).

Dr Wysock presented data from two pivotal studies evaluating the usefulness of MRI-guided biopsies for cancer detection: the PROMIS, Diagnostic accuracy of multiparametric magnetic resonance imaging and TRUS biopsy in prostate cancer (PROMIS), and PRECISION, MRI Targeted Biopsy vs Standard Biopsy in Prostate Cancer Diagnosis: (The PRECISION Trial).

In the PROMIS study, men underwent both MRI-guided and TRUS-guided biopsy, which was then compared to the standard of a transperineal mapping biopsy.¹. The authors noted that MRI-guided biopsies were more sensitive for clinically significant prostate cancer detection than TRUS-guided biopsies alone. In the PRECISION study, men were randomized to either standard TRUS guided biopsy or a direct MRI strategy, in which the men underwent a targeted biopsy if the prostate MRI was for prostate cancer.². It was found that more men randomized to MRI have clinically significant prostate cancer than men undergoing TRUS-guided biopsy (38% and 26%, respectively). Additionally, men randomized to the MRI arm were less likely to have biopsies identifying clinically insignificant disease than men in the TRUS guided biopsy arm. Importantly, about 20% of men randomized to the MRI arm avoided a biopsy altogether due to the reassuring results of MRI. These studies suggest that MRI stratified biopsy strategies are superior in detecting clinically significant prostate cancer while minimizing the detection of clinically insignificant disease.

Highlighting some limitations of biopsies aimed at MRI and MRI, Dr. Wysock presented data from Sonn et al. which demonstrates significant inter-observer variability among radiologists reading MRI of the prostate, assigning PIRADS scores and subsequent detection of clinically significant tumors³. Hopefully, with standardization and improved familiarity with MRI and MRI-guided biopsies, variability will decrease among radiologists assigning PIRADS scores and corresponding cancer detection on targeted biopsies, thereby further improving the usefulness. of these technologies.

Dr. Wysock briefly discusses the role of MRI as a potential screening tool for prostate cancer, proposing that MRI may work in the future similar to mammography for breast cancer or lung cancer with low-dose CT scan. , two types of cancer that screening programs depend heavily on imaging modalities. Additionally, 29Mhz high-resolution micro-ultrasound is an emerging technology that could play a clinically significant role in prostate cancer screening and detection in the future, although these data are still immature.

Leveraging MRI and other advanced imaging technologies show significant promise and greater accuracy than the status quo in nearly all prostate cancer care states, including screening, detection, staging, and monitoring of men with cancer to the prostate. This author looks forward to further studies integrating these technologies into prostate cancer screening, detection and treatment paradigms.

Presented by: Dr. James Wysock, MD, MSc. Urological Oncologist, NYU Langone Health, New York, New York, United States.

Written by: Kevin Ginsburg, MD, and Adrien Bernstein, MD, Society of Urologic Oncology Fellow, Fox Chase Cancer Center, Fox Chase Cancer Center, Philadelphia, PA, at the Annual Meeting of the Society of Urological Oncology 2020 – December 2-5, 2020 – Washington DC

References
1. Ahmed, HU, El-Shater Bosaily, A., Brown, LC et al. Diagnostic Accuracy of Multiparameter MRI and TRUS Biopsy in Prostate Cancer (PROMIS): A Paired Validation Confirmation Study. Hand, 389:815, 201
2. Kasivisvanathan, V., Rannikko, AS, Borghi, M. et al. MRI or standard biopsy for prostate cancer diagnosis. N Engl J Med, 378: 1767, 2018
3. Sonn, GA, Fan, RE, Ghanouni, P. et al. MRI interpretation of the prostate varies greatly among radiologists. Eur Urol Focus, 5: 592, 2019