Does the introduction of prostate multiparametric magnetic resonance imaging into the active surveillance protocol for localized prostate cancer improve patient re-classification?
OBJECTIVES
To determine whether replacement of protocol-driven repeat prostate biopsy (PB) with multiparametric magnetic resonance imaging (mpMRI) ± repeat targeted prostate biopsy (TB) when evaluating men on active surveillance (AS) for low-volume, low- to intermediate-risk prostate cancer (PCa) altered the likelihood of or time to treatment, or reduced the number of repeat biopsies required to trigger treatment.


PATIENTS AND METHODS
A total of 445 patients underwent AS in the period 2010-2016 at our institution, with a median (interquartile range [IQR]) follow-up of 2.4 (1.2-3.7) years. Up to 2014, patients followed a 'pre-2014' AS protocol, which incorporated PB, and subsequently, according to the 2014 National Institute for Health and Care Excellence (NICE) guidelines, patients followed a '2014-present' AS protocol that included mpMRI. We identified four groups of patients within the cohort: 'no mpMRI and no PB'; 'PB alone'; 'mpMRI ± TB'; and 'PB and mpMRI ± TB'. Kaplan-Meier plots and log-rank tests were used to compare groups.


RESULTS
Of 445 patients, 132 (30%) discontinued AS and underwent treatment intervention, with a median (IQR) time to treatment of 1.55 (0.71-2.4) years. The commonest trigger for treatment was PCa upgrading after mpMRI and TB (43/132 patients, 29%). No significant difference was observed in the time at which patients receiving a PB alone or receiving mpMRI ± TB discontinued AS to undergo treatment (median 1.9 vs 1.33 years; P = 0.747). Considering only those patients who underwent repeat biopsy, a greater proportion of patients receiving TB after mpMRI discontinued AS compared with those receiving PB alone (29/66 [44%] vs 32/87 [37%]; P = 0.003). On average, a single set of repeat biopsies was needed to trigger treatment regardless of whether this was a PB or TB.


CONCLUSIONS
Replacing a systematic PB with mpMRI ±TB as part of an AS protocol increased the likelihood of re-classifying patients on AS and identifying men with clinically significant disease requiring treatment. mpMRI ±TB as part of AS thereby represents a significant advance in the oncological safety of the AS protocol.
['Bryant|Richard J|RJ|0000-0002-8330-9251', 'Yang|Bob|B|0000-0002-3136-2747', 'Philippou|Yiannis|Y|', 'Lam|Karla|K|', 'Obiakor|Maureen|M|', 'Ayers|Jennifer|J|', 'Chiocchia|Virginia|V|', 'Gleeson|Fergus|F|', 'MacPherson|Ruth|R|', 'Verrill|Clare|C|', 'Sooriakumaran|Prasanna|P|', 'Hamdy|Freddie C|FC|', 'Brewster|Simon F|SF|']
D000368:Aged D001706:Biopsy D018450:Disease Progression D006801:Humans D053208:Kaplan-Meier Estimate D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D011467:Prostate D011471:Prostatic Neoplasms D012189:Retrospective Studies D061665:Time-to-Treatment
active surveillance prostate cancer mpMRI repeat biopsy