Oncological Outcomes of Metastasis-Directed Therapy in Oligorecurrent Prostate Cancer Patients Following Radical Prostatectomy

Abstract

Several retrospective and a few prospective studies have shown that metastasis-directed therapy (MDT) could delay clinical progression and postpone the initiation of systemic treatment in oligorecurrent prostate cancer (PCa) patients. However, these endpoints are strongly influenced by variables such as concomitant use of androgen deprivation therapy (ADT) and follow-up imaging protocols. The aim of this manuscript was to assess palliative ADT- and metastatic castration-resistant prostate cancer (mCRPC)-free survival as long-term oncological outcomes in oligorecurrent PCa treated by MDT. We retrospectively identified consecutive post-prostatectomy oligorecurrent PCa patients treated by MDT (salvage lymphadenectomy, radiotherapy, or metastasectomy) at our tertiary referral center. Patients were eligible for inclusion if they developed recurrence following radical prostatectomy, had ≤5 metastatic lesions on imaging and had a serum testosterone >50 ng/dL or a testosterone suppression therapy-free interval of >2 years prior to the first MDT as an assumption of recovered serum testosterone (if no testosterone measurement available). Patients with castration-resistant or synchronous oligometastatic PCa at the time of first MDT were excluded. Repeated MDTs were allowed, as well as a period of concomitant ADT. Kaplan-Meier analyses were performed to assess palliative ADT-free and mCRPC-free survival. We identified 191 eligible patients who underwent MDT. Median follow-up from first MDT until last follow-up or death was 45 months (IQR 27-70; mean 51 months). Estimated median palliative-ADT free survival was 66 months (95% CI 58-164) and estimated median mCRPC-free survival was not reached (mean 117 months, 95% CI 103-132). In total, 314 MDTs were performed and 25 patients (13%) received ≥3 MDTs. This study demonstrated that (repeated) MDT is feasible and holds promise in terms of palliative ADT-free and mCRPC-free survival for patients with oligorecurrent PCa. However, these findings should be confirmed in prospective randomized controlled trials.

Keywords: SBRT; metastasectomy; metastasis directed therapy; oligometastatic prostate cancer; oligorecurrent prostate cancer; salvage lymphadenectomy.

Figure 1

Palliative ADT-free survival (n = 191). Censored patients are marked with small vertical lines. The 95% confidence interval is provided (thin lines).

Figure 2

mCPRC-free survival (n = 191). Censored patients are marked with small vertical lines. The 95% confidence interval is provided (thin lines).

Figure 3

Breakdown of patients who received multiple MDTs. A distinction is made between patients with ≤3 new/progressive lesions and patients with >3 new/progressive lesions. ADT = androgen deprivation therapy; MDT = metastasis-directed therapy; PCa = prostate cancer; RT = radiotherapy; sLND = salvage lymphadenectomy.