Introduction:

Radical prostatectomy (RP) is a common form of definitive treatment for men with localized prostate cancer. Such patients are followed with serial PSA testing. A detectable postoperative serum PSA is thought to represent treatment failure and such patients are often offered salvage therapy while those with an undetectable PSA are monitored closely. We aim to better characterize the natural history of patients with an immediately versus delayed detectable serum PSA after RP using a “hypersensitive” PSA cut point (0.03 ng/ml), a more contemporary value.

Methods:

A retrospective analysis of men who underwent RP for non-metastatic prostate cancer at the University of California, San Francisco from 2000 to 2021, who consented for research, and had extensive follow-up was performed. Each participant in the delayed group reached an undetectable post-operative PSA within 6 months. The primary outcome was biochemical recurrence, defined as 2 consecutive PSA>=0.03 starting 6 months after surgery. Secondary outcomes were salvage treatment, post-salvage treatment, metastasis (nodal or bone) free survival (MFS), prostate cancer specific mortality (PCSM), and all-cause mortality (ACM).

Results:

From our cohort of 3132 patients, we identified 2684 men who had an undetectable post-op PSA. Surgical CAPRA-S was 54% low, 36% intermediate, and 10% high risk. The median follow-up after RP was 55 months. Subsequently, 646 men had a delayed detectable PSA at a median time of 29 months (IQR 16, 54). The immediate versus delayed groups differed in the receipt of salvage therapy (73% vs 42%), as well as ACM (12% vs 5%), PCSM (8% vs 2%) and MFS (79% vs 92%) within 10 years [Table 1].

In the subcohort of 222 delayed detectable patients who underwent salvage treatment within 10 years of surgery, 63% of men had recurrent PSA failure.  Those who received tertiary treatment versus those who were monitored differed significantly in ACM (22% vs 3%), PCSM (22% vs 0%) and MFS (70% vs 93%), all log rank <0.01 [Table 2].

Conclusion:

Men who develop a detectable serum PSA >6 months post-operatively may have excellent long-term outcomes. Such information can be used to assess the timing and type of additional treatment.

Funding: UCSF Goldberg-Benioff Program in Translational Cancer Biology