De-escalation prostate cancer treatment

 PSMA PET to determine need for PLND at the time of RP

1. If PSMA PET is neg for nodal mets in intermediate risk, Neg predictive value is 90% and PLND can be omitted.

2. For high risk prostate ca, PSMA PET neg predictive value is 80%. 

3. Typically PLND is done if normograms estimate 5% or higher risk. It is associated with increased nerve and vessel damage, with VTE and lymphedema as complications.

Delay in systemic therapy in oligometastatic prostate ca

OLIGOPELVIS GETUG-07 trial is a phase II study including 67 patients who experienced limited nodal recurrence (up to five PET-positive LNs) detected by fluorocholine PET/CT. Combined high-dose salvage pelvic radiotherapy and ADT (6 months) resulted in 2- and 3-year progression-free survival rates of 81% and 58%, respectively. The 2- and 3-year biochemical progression-free survival rates were 58% and 46%, respectively.

A large retrospective cohort including 2,079 patients (MDT cohort n = 263, immediate or delayed ADT cohort n = 1,816) showed improved cancer-specific survival for local therapy with salvage lymph node dissection (sLND) or SBRT compared with standard of care (immediate or delayed ADT at PSA progression) in patients with nodal oligorecurrence after multimodality treatment.

What constitutes adjuvant radiation after RP: radiation given within 6 months of RP if path with high risk features ( Positive margins, T3/T4, SV involvement, Gleason 8 -10).

Salvage RT is RT given at ANY TIME after RP for rising PSA.

Predictors of recurrence in oligometastatic disease following metastasis directed therapy:

1. Node positive:  cN1 subgroup revealed that lower iPSA at the time of RP, pN stage at RP, nonpersisting PSA after RP (meaning PSA below 0.1 ng/ml at least 30 d after RP), higher PSA at primary MDT, and an increased number of positive nodes on imaging were associated with worse MFS outcomes

2. Non nodal mets: high-grade pathological Gleason score, a lower number of lesions on imaging, and cM1b/cM1c (non-nodal metastatic recurrence) were more likely to have shorter MFS. 

Reference: https://ascopubs.org/doi/full/10.1200/EDBK_430466