For the right prostate cancer (PCa) patient, Active Surveillance (AS) is a good thing. Urologic professionals now see eye-to-eye on monitoring with a focus on “preventing overtreatment in patients for whom the benefit of treatment deferral outweighs the need for immediate oncologic control.”^[i] That’s a technical way of saying, if you don’t have clinically significant PCa that needs immediate treatment, you can safely put off going through a procedure that may compromise your urinary, sexual or bowel quality of life.

While it’s great that all clinicians agree on that point. However, they differ somewhat on the criteria for enrolling a patient into AS. The broad standard includes men with low- to favorable risk intermediate PCa based on T-stage, PSA, and Gleason score. However, many clinicians take additional factors into account (e.g., PSA density, number of positive cores, percent of tumor involvement in individual cores) before they have peace of mind about recommending AS for a given patient.

To achieve the best possible assurance on that score, all major urologic associations here and abroad now recommend a baseline multiparametric MRI (mpMRI) of the prostate before making a final AS determination. Baseline imaging results in one of two categories:

a) Suspicious lesion(s) are visible, or
b) There are no visible suspicious lesions.

In either case, repeat MRIs during surveillance helped reduce the number of repeat biopsies, which in turn raised compliance with AS protocols which were compromised when AS patients avoided repeat surveillance biopsies. Thankfully, interval monitoring with PSA+MRI was considered sufficient to detect disease progression, which then triggers a move to definitive treatment with intent to cure.

However, to assure even greater consistency in assessing and reporting successful AS—and deciding when and how to trigger a move to treatment—in 2016 a consensus panel of 24 international experts came together to establish a set of guidelines called The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE). It would benefit patients on AS, and ensure the trustworthiness of monitoring based on consistent MRI detection and reporting of cancer progression. Key points included “reporting the index lesion size using absolute values at baseline and at each subsequent MRI. Radiologists should assess the likelihood of true change over time (ie, change in size or change in lesion characteristics on one or more sequences) on a 1-5 scale.”^[ii]

In the next 5+ years of implementation, however, problems showed up. inconsistencies among diagnostic/treatment centers began showing up, partly due to circumstances such as different magnet strengths, varying degrees of radiologic reader experience, and differing AS criteria and protocols. In addition, it seemed that the PRECISE 1-5 scale in itself was not adequate to cover certain ambiguous PCa characteristics on MRI, making it difficult to neatly assign them to one of the 5 categories.

Thus, in June 2023 a team of British clinicians/researchers conducted a critical review of the use of PRECISE to “support the use of progression on MRI as a trigger for a confirmatory biopsy rather than as a direct indication for treatment.”^[iii] They note that the use of MRI to monitor AS is implemented far less than its use for initial diagnosis, and suggest that difficulties in applying the PRECISE recommendations as initially written may be one reason behind this.

To improve the ease of using PRECISE in order to integrate MRI smoothly, accurately and consistently in surveillance protocols, the authors propose the following seven improvements:

1. The image quality of the MRI scans will vary based on a range of factors including patient position, experience level of the reader, differing magnet strengths, etc. If the quality of the baseline scan is subpar, it will make serial comparisons difficult to interpret. The imaging protocol should be PI-RADS compliant.
2. Add a PRECISE category for MRI-invisible disease and its follow-up examinations.
3. Define quantitative thresholds for determining significant progression, especially for T2- weighted and diffusion-weighted MRI sequences (parameters).
4. Adopt defined criteria for overall patient-level scores to incorporate unusual or ambiguous individual cases (e.g., stable index lesion but progression in secondary tumors).
5. Implement a subcategory for lesions that show slight but not significant progression, scoring such progression based on comparison with the baseline scan and the most recent prior one. 6. Reset the baseline if either a triggered biopsy shows unchanged findings, or in patients who initiate certain treatment for BPH.
6. Clearly define a PRECISE score of 5 as progression from localized disease to non-localized PCa, and to not use that score for patients with prior MRI-invisible disease who now develop a visible localized lesion—suggest assigning such cases a PRECISE score of 4.

Given the global acceptance of mpMRI in the diagnostic pathway of initial diagnosis of PCa, it makes clear sense to incorporate it consistently in monitoring AS patients for progression. The authors hope that these suggested changes will improve the usefulness of the PRECISE 5-point scoring system in order to not for AS data and research purposes, but more importantly to support patient participation in their monitoring protocol, and to clearly know when it’s time to move to definitive treatment.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

[i] Sanmugalingam N, Sushentsev N, Lee KL et al. The PRECISE Recommendations for Prostate MRI in Patients on Active Surveillance for Prostate Cancer: A Critical Review. AJR Am J Roentgenol. 2023 Jun 21.
[ii] Moore CM, Giganti F, Albertsen P, Allen C et al. Reporting Magnetic Resonance Imaging in Men on Active Surveillance for Prostate Cancer: The PRECISE Recommendations-A Report of a European School of Oncology Task Force. Eur Urol. 2017 Apr;71(4):648-655.
[iii] Sanmugalingam et al.