Follow-up modalities in focal therapy for prostate cancer: results from a Delphi consensus project

Focal therapy can offer the middle ground for treatment between active surveillance and radical therapy in patients with low- and intermediate-risk prostate cancer. Factors that prohibit focal therapy from being standard of care are numerous. Several consensus projects have been conducted to position the utilization of imaging and trial design in focal therapy. However, the literature is still scarce on patient follow-up after focal therapy. For these reasons, an international multidisciplinary consensus project was established in order to reach consensus about a uniform follow-up protocol after focal therapy.

To standardize patient follow-up after focal therapy.

A literature study was performed, and a questionnaire was constructed. The questionnaire was sent out to 76 participants (70 % urologists, 28 % radiologists and 2 % biomedical engineers) in three consecutive rounds according to the Delphi method. In each round, the panelists were presented with the results of the previous round. Participants each had the opportunity to adapt, delete or add questions. The topics discussed pertaining to follow-up after focal therapy were as follows: (1) general,(2) biopsies, (3) PSA, (4) digital rectal examination (DRE), (5) imaging, (6) quality of life (QoL) and (7) registration and pooling of data. The project was concluded with a face-to-face meeting in which final conclusions were formulated.

The follow-up after focal therapy should be a minimum of 5 years. The following modalities should be included in assessing post-treatment outcomes: multiparametric MRI (mpMRI), biopsies, assessment of erectile function, QoL, urinary symptoms and incontinence. A systematic 12-core TRUS biopsy combined with 4-6 targeted biopsy cores of the treated area and any suspicious lesion(s) should be performed after 1 year, and thereafter only when there is suspicion on imaging. The ideal way to perform targeted biopsies is to use TRUS-MRI fusion technology. PSA should be performed for research purposes, in the first year, every 3 months, and after the first year, every 6 months. mpMRI is the optimal imaging modality for follow-up after focal therapy. On a 1.5T scanner, an endorectal coil is strongly advised by the panel, whereas on a 3T machine, it is optional, however, it will improve image quality. The following sequences should be included: T2WI, DWI including high b values of >1,000 and ADC maps of DWI, DCE and T1WI. Imaging should be performed at 6 months and at 1 year following treatment; after the first year post-treatment, it should be performed every year until 5 years following treatment. All data should ideally be pooled in a common global database.

Focal therapy is a relatively new form of treatment for prostate cancer. In order to include focal therapy as a standard of care treatment, consistent follow-up is necessary. By implementing the results of this consensus study, focal therapy users will be able to provide important and standardized outcome data.