PEACE V: Salvage Treatment of OligoRecurrent Nodal Prostate Cancer Metastases

Overview

A proportion of prostate cancer (PCa) patients develop relapse following curative local treatment. Regional nodal recurrence is an emerging clinical situation since the introduction of new molecular imaging methods in the restaging of recurrent prostate cancer. More specifically, a subgroup of these patients is being diagnosed with a recurrence confined to the regional lymph nodes and limited in number (oligorecurrence) using choline or PSMA PET-CT. As there are no specific treatment recommendations for these type of patients, different treatment approaches are currently used, mostly focusing on local ablative treatments using radiotherapy or surgery. These treatments are coined metastasisdirected therapy (MDT). MDT in combination with or without temporary ADT could delay the subsequent risk of progression, and even cure limited regional nodal recurrences. Consequently, lifelong palliative ADT, with its toxicity and excess in non-cancer mortality might be postponed. The proposed trial randomizes patients with oligorecurrent nodal prostate cancer following primary PCa treatment to either metastasis-directed therapy (MDT) (salvage lymph node dissection, sLND or stereotactic body radiotherapy, SBRT) or MDT plus whole pelvis radiotherapy (WPRT: 45 Gy in 25 fractions).

A proportion of prostate cancer (PCa) patients develop a local, regional (N1) or distant (M1) relapse following curative local treatment. For both local and distant relapses, different treatment recommendations are made in the guidelines (EAU guidelines 2016). However, the entity regional nodal recurrence is not mentioned in the guidelines but is an emerging clinical situation since the introduction of choline and more recently PSMA PET-CT in the restaging of recurrent prostate cancer. More specifically, a subgroup of these patients is being diagnosed with a recurrence confined to the regional lymph nodes and limited in number (oligorecurrence) using choline or PSMA PET-CT. As there are no specific treatment recommendations for these type of patients, different treatment approaches are currently used, mostly focusing on local ablative treatments using radiotherapy or surgery. These treatments are coined metastasisdirected therapy (MDT). MDT in combination with or without temporary ADT could delay the subsequent risk of metastases, and even cure limited regional nodal recurrences. Consequently, lifelong palliative ADT, with its toxicity and excess in non-cancer mortality might be postponed. The proposed trial randomizes patients with oligorecurrent nodal prostate cancer following primary PCa treatment to either metastasis-directed therapy (MDT) (sLND or SBRT) or MDT plus WPRT. In the recurrent PCa setting, 2 recent trials have suggested a progression-free and even survival benefit of adding temporary ADT to local salvage prostate bed radiotherapy. Consequently, this positive effect might also be applicable for regional recurrences. Although the optimal duration of ADT is unknown, a minimal duration of 6 months of ADT seems advisable in this setting and will be mandatory for both arms. This trial will improve our insights in the pattern of recurrence following these treatment modalities with the expectation that WPRT will reduce the number of nodal relapses, improving metastasis-free survival and postponing the need for palliative systemic treatments while maintaining quality-of-life. The current phase II trial will try to establish a golden standard in the treatment of oligorecurrent nodal PCa.