Surveillance or metastasis-directed therapy for oligometastatic prostate cancer recurrence (STOMP): Five-year results of a randomized phase II trial.

Abstract

10 Background: Multiple randomized phase II trials suggest that metastasis-directed therapy (MDT) for oligometastatic prostate cancer (PCa) improves progression-free survival, but the majority of trials lack longer follow-up. We present the updated 5-year results from the STOMP-trial. Methods: In this multicentre, randomised, phase II study, asymptomatic PCa patients were eligible in case of a biochemical recurrence following primary PCa treatment with curative intent and presenting with up to 3 extracranial on choline PET-CT and a serum testosterone levels > 50 ng/ml. Patients were randomly assigned (1:1) to either surveillance or MDT of all detected lesions. Randomisation was balanced dynamically on two factors: PSA doubling time (≤3 vs. > 3 months) and nodal vs non-nodal metastases. The primary endpoint was androgen deprivation therapy (ADT)-free survival. Castrate resistant prostate cancer-free survival (CRPC) was a secondary endpoint. Tests were performed two-sided; p values less than 0.20 were deemed significant. Results: The 5-year ADT-free survival was 8% for the surveillance group and 34% for the MDT group (Figure 1, hazard ratio 0.57 [80% CI: 0.38-0.84], log-rank p = 0.06). There was no significant difference in effect for the different stratification factors (interaction test). The 5-year CRPC-free survival was 53% for the surveillance group and 76% for the MDT group (hazard ratio 0.62 [80% CI: 0.35−1.09]; log−rank p = 0.27). At a median follow for survival of 5.3 years (IQR 4.3-6.3), the 5-year overall survival was 85%, with 6 out of 14 deaths attributed to prostate cancer. Conclusions: The updated STOMP trial outcomes confirm the earlier reported significant difference in ADT free survival in favor of the MDT group compared to surveillance. Prostate-cancer related mortality is low within the first 5 years of diagnosis of oligorecurrent prostate cancer. Clinical trial information: NCT01558427.

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

“…With a median follow-up of 3 years, mCRPC-free survival was almost 90% in both groups which is similar to our findings (93% at 3 years follow-up). In addition, an update of the STOMP trial showed that the 5-year mCRPC free survival was 76% in the MDT group which is also similar to our results (82% at five years) [ 24 ]. Suardi et al reported long-term outcomes of 59 oligorecurrent PCa patients treated by sLND with a median follow-up of more than 6 years [ 9 ].…”

Rationale for Involved Field Stereotactic Body Radiation Therapy-Enhanced Intermittent Androgen Deprivation Therapy in Hormone-Sensitive Nodal Oligo-Recurrent Prostate Cancer Following Prostate Stereotactic Body Radiation Therapy

“…Progression at 6 months occurred in 61% of the patients in the observation arm but only 19% in the treated group. With increased follow-up of the STOMP trial, data is emerging that patients treated with MDT may experience increased time to castrate resistance ( 54 ). Criticisms of these trials include the lack of control arm of immediate ADT and the use of the surrogate end point ADT-free survival, however, for older men, with limited life expectancy this remains a clinically meaningful endpoint.…”

“…We hypothesize that involved field SBRT will decrease tumor burden in lymph nodes and delay transition to bone metastases and castration resistance ( 54 ). However, if involved field SBRT to oligo-recurrent nodal disease causes a significant rate of high-grade late toxicity and/or adversely affected patients' long-term quality of life this approach would not be worth pursuing further.…”

Nuclear Imaging for Bone Metastases in Prostate Cancer: The Emergence of Modern Techniques Using Novel Radiotracers

“…The most studied treatment approach in patients with oligometastatic recurrent PCa, is metastasis-directed local therapy (MDT; for example, stereotactic radiotherapy or surgery), with the potential goals of delaying the start of ADT and influencing prognosis [ 56 ]. A recent randomized phase II study of patients with oligometastatic recurrent PCa showed improved ADT-free survival in patients who underwent MDT compared to surveillance [ 57 ]. The effect of MDT on OS needs to be addressed in further clinical trials.…”