Factors affecting the selection of eligible candidates for focal therapy for prostate cancer

Focal therapy (FT) is a treatment modality for prostate cancer that aims to reduce side effects. However, it remains difficult to select eligible candidates. We herein examined eligibility factors for hemi-ablative FT for prostate cancer.

We identified 412 patients who were diagnosed with unilateral prostate cancer by biopsy and had undergone radical prostatectomy between 2009 and 2018. Among these patients, 111 underwent MRI before biopsy, had 10-20 core biopsies performed, and did not receive other treatments before surgery. Fifty-seven patients with prostate-specific antigen ≥ 15 ng/mL and biopsy Gleason score (GS) ≥ 4 + 3 were excluded. The remaining 54 patients were evaluated. Both lobes of the prostate were scored using Prostate Imaging Reporting and Data System version 2 on MRI. Ineligible patients for FT were defined as those with ≥ 0.5 mL GS6 or GS ≥ 3 + 4 in the biopsy-negative lobe, ≥ pT3, or lymph node involvement. Selected predictors of eligibility for hemi-ablative FT were analyzed.

Among our cohort of 54 patients, 29 (53.7%) were eligible for hemi-ablative FT. A multivariate analysis identified a PI-RADS score < 3 in the biopsy-negative lobe (p = 0.016) as an independent predictor of eligibility for FT. Thirteen out of 25 ineligible patients had GS ≥ 3 + 4 tumors in the biopsy-negative lobe, half of whom (6/13) also had a PI-RADS score < 3 in the biopsy-negative lobe.

The PI-RADS score in the biopsy-negative lobe may be important in the selection of eligible candidates for FT. The findings of this study will help reduce missed significant prostate cancers and improve FT outcomes.