Imaging Characteristics of Prostate Cancer Patients Who Discontinued Active Surveillance on 3-T Multiparametric Prostate MRI.

OBJECTIVE: Early-stage prostate cancer may be followed with active surveillance to avoid overtreatment. Our institution's active surveillance regimen uses annual MRI in place of serial biopsies, and biopsies are performed only when clinically necessary. The objective of our study was to report the multiparametric MRI characteristics of prostate cancer patients who discontinued active surveillance at our institution after repeat imaging revealed possible evidence of tumor upgrading.

MATERIALS AND METHODS: The Department of Urology at Winthrop University Hospital prospectively maintains a database of prostate cancer patients who are monitored with active surveillance. At the time of this study, there were 200 prostate cancer patients being monitored with active surveillance. Of those patients, 114 patients had an initial multiparametric MRI study that was performed before active surveillance started and at least one follow-up multiparametric MRI study that was performed after active surveillance began. The MRI findings were evaluated and correlated with pathology results, if available.

RESULTS: Fourteen patients discontinued active surveillance because changes on follow-up MRI suggested progression of cancer. Follow-up MRI showed an enlarged or more prominent lesion compared with the appearance on a previous MRI in three (21.4%) patients, a new lesion or lesions suspicious for cancer in two (14.3%) patients, and findings suspicious for or confirming extracapsular extension in nine (64.3%) patients. Seven of the 14 (50.0%) patients had a biopsy after follow-up multiparametric MRI, and biopsy results led to tumor upgrading in six of the 14 (42.9%) patients. The duration of active surveillance ranged from 4 to 110 months. All patients received definitive treatment.

CONCLUSION: The small number of patients with follow-up multiparametric MRI findings showing worsening disease supports the role of MRI in patients with early-stage prostate cancer. Multiparametric MRI is useful in monitoring patients on active surveillance and may identify patients with clinically significant cancer amenable to definitive treatment.