Recurrent Gleason Score 6 Prostate Cancer After Radiotherapy or Ablation: Should We Observe Them All? Results from a Large Multicenter Salvage Radical Prostatectomy Consortium

Background

Salvage radical prostatectomy (sRP) yields poor functional outcomes and relatively high complication rates. Gleason score (GS) 6 prostate cancer (PCa) has genetic and clinical features showing little, if not absent, metastatic potential. However, the behavior of GS 6 PCa recurring after previous PCa treatment including radiotherapy and/or ablation has not been investigated.

Objective

To evaluate the oncological outcomes of sRP for radio- and/or ablation-recurrent GS 6 PCa.

Design, setting, and participants

Retrospective data of sRP for recurrent PCa after local nonsurgical treatment were collected from 14 tertiary referral centers from 2000 to 2021.

Intervention

Prostate biopsy before sRP and sRP.

Outcome measurements and statistical analysis

A survival analysis was performed for pre-sRP biopsy and sRP-proven GS 6. Concordance between PCa at pre-sRP biopsy and sRP histology was assessed.

Results and limitations

We included GS 6 recurrent PCa at pre-sRP biopsy (n = 142) and at sRP (n = 50), as two cohorts. The majority had primary radiotherapy and/or brachytherapy (83.8% of GS 6 patients at pre-sRP biopsy; 78% of GS 6 patients at sRP) and whole-gland treatments (91% biopsy; 85.1% sRP). Biopsy GS 6 10-yr metastasis, cancer-specific survival (CSS), and overall survival (OS) were 79% (95% confidence interval [CI] 61–89%), 98% (95–99%), and 89% (78–95%), respectively. Upgrading at sRP was 69%, 35.5% had a pT3 stage, and 13.4% had positive nodes. The sRP GS 6 10-yr metastasis-free survival, CSS, and OS were 100%, 100%, and 90% (95% CI 58–98%) respectively; pT3 and pN1 disease were found in 12% and 0%, respectively. Overall complications, high-grade complications, and severe incontinence were experienced by >50%, >10%, and >15% of men, respectively (in both the biopsy and the sRP cohorts). Limitations include the retrospective nature of the study and absence of a centralized pathological review.

Conclusions

GS 6 sRP–proven PCa recurring after nonsurgical primary treatment has almost no metastatic potential, while patients experience relevant morbidity of the procedure. However, a significant proportion of GS 6 cases at pre-sRP biopsy are upgraded at sRP. In the idea not to overtreat, efforts should be made to improve the diagnostic accuracy of pre-sRP biopsy.

Patient summary

We investigated the oncological results of salvage radical prostatectomy for recurrent prostate cancer of Gleason score (GS) 6 category. We found a very low malignant potential of GS 6 confirmed at salvage radical prostatectomy despite surgical complications being relatively high. Nonetheless, biopsy GS 6 was frequently upgraded and had less optimal oncological control. Overtreatment for recurrent GS 6 after nonsurgical first-line treatment should be avoided, and efforts should be made to increase the diagnostic accuracy of biopsies for recurrent disease.