MP17-10 (Poster): Neo active surveillance for patients with negative upfront prostate MRI.

Neo active surveillance for patients with negative upfront prostate MRI.

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INTRODUCTION

Evidence for use of MRI to triage for initial prostate biopsy is increasing. However, to our knowledge, there is no literature to date on actual follow-up of patients with a negative prostate MRI who avoid an initial biopsy – what we term Neo Active Surveillance (NAS). We present our clinical experience of patients on NAS.

METHODS

From July 2013 to September 2017, a prospective IRB-approved database (REDCap) was kept on all patients in our group urology practice who underwent MRI for suspicion of prostate cancer. The database was queried for all men with no prior prostate biopsy who had a negative MRI (PIRADS 1 or 2) and who did not undergo a biopsy within 6 months after the MRI. Metrics analysed included patient age, PSA, %free PSA and Prostate Health Index (PHI) at time of MRI, PSA density and duration of follow-up. Results of any subsequent MRI, any first biopsy greater than 6 months from the original MRI, and any subsequent radical prostatectomy pathology were also recorded. Significant cancer was defined as any Gleason score 3+4=7 (ISUP Grade Group 2) or greater.

RESULTS

Of 1966 patients in the database, 1254 (64%) had an MRI without any prior biopsy. Of these 1254 men, 686 (55%) had a negative MRI (PIRADS 1 or 2). Of these 686 men, a cohort of 294 (43%) were under NAS and had at least 6 months follow-up. For this NAS cohort of 294 men, mean age was 63, mean PSA was 4.9, mean %free PSA was 21.8%, mean PHI was 38.5 (normal 0-45), and mean PSA density was 0.12. Mean duration of follow-up from initial MRI was 16.1 months (range 6 - 43 months). 30 (10.2%) patients had a subsequent MRI, of which 22 (73%) remained negative. 32 (10.8%) patients had their first biopsy greater than 6 months after MRI, of which 11 (4%) showed significant cancer (6 were Grade Group 2). Their mean PSA density was 0.19. 8 of those men underwent radical prostatectomy. Of these, only 1 had pT3 disease and all specimens were margin negative.

CONCLUSION

This initial real-life clinical experience of avoiding biopsy in selected men with suspicion of prostate cancer based on elevated PSA or abnormal DRE, but with a negative MRI and subsequent monitoring (Neo Active Surveillance) supports the safe use of this practice, with only 4% of men showing significant cancer on subsequent biopsy. NAS in our hands reduced biopsy by 89% (from 294 to 32). However, we caution that all MRIs were read by highly experienced radiologists and that clinical factors other than a negative MRI must also be taken into account in triaging for biopsy.

Funding: Tolmar, Abbvie, AstraZeneca, Ipsen.