Post-Metastasis Survival of Patients with High-Risk Localized and Locally Advanced Prostate Cancer Undergoing Primary Treatment in the United States: A Retrospective Study.

BACKGROUND

Patients with high-risk localized and locally advanced prostate cancer (HR-LPC/LAPC) have increased risk of metastasis, leading to reduced survival rates. Segmenting the disease course [time to recurrence, recurrence to metastasis, and post-metastasis survival (PMS)] may identify disease states for which the greatest impacts can be made to ultimately improve survival.

OBJECTIVE

Evaluate real-world PMS of patients with HR-LPC/LAPC who received primary radical prostatectomy (RP) or radiotherapy (RT) with or without androgen deprivation therapy (ADT).

PATIENTS AND METHODS

Electronic health records from an oncology database were used to assess PMS. Risk of death was estimated using the Kaplan-Meier method. Hazard ratios (HRs) were used to analyze the impact of treatment and time to metastasis (TTM) on PMS. Standardized mortality ratios (SMRs) were calculated for patients with HR-LPC/LAPC versus the US general male population.

RESULTS

Overall, 5008 patients with HR-LPC/LAPC were identified, and 1231 developed metastases after primary treatment (RP, n = 885; RT only, n = 262; RT+ADT, n = 84). Age-adjusted PMS HR between the RP and RT only cohorts was 1.19 (p = 0.077) and between RP and RT+ADT cohorts was 1.32 (p = 0.078). TTM was unrelated to PMS in unadjusted (HR 1.01, p = 0.2) and age-adjusted models (HR 0.99, p = 0.3). Relative to pre-metastasis SMRs, post-metastasis SMRs increased eightfold and fivefold in patients treated with RP and RT±ADT, respectively.

CONCLUSIONS

PMS was unrelated to TTM in patients with HR-LPC/LAPC, suggesting PMS may be independent of the trajectory to development of metastases. Given PMS may be a fixed length of time, delaying the development of metastasis may improve survival in patients with HR-LPC/LAPC.