When do you start ADT for a patient with a new diagnosis of node positive prostate cancer receiving radiation?

I would reverse the question order. For node-positive disease, I start ADT once staging imaging is complete. If logistically practical (as with high-risk localized), I often perform the simulation and start ADT at the same time, then start RT without a neoadjuvant period. Evidence for neoadjuvant ADT is relatively weak, and if you want to perform an integrated boost to the focal lesion and/or the positive nodes, it is easier to do that when the tumors are visible. If logistically advantageous to wait, I will wait at least 5-6 weeks for the sim and start treatment ~8 weeks after starting ADT.

We usually start upfront and start RT in a few months. This helps to see nodal response, can also sometimes help meet small bowel constraints with regression, and can also adjust the total dose if needed.

ASTRO 2022: Predictive Value of Ga68-PSMA PETCT-Based Response to Neoadjuvant Androgen Deprivation Therapy in Node Positive Prostate Cancer Treated with Radical Radiotherapy

8 weeks prior to treatment planning

I have spent the last 25 years with a consistent philosophy about nodes and ADT. My basis: nodes are signposts of systemic disease that have yet to manifest. ADT is not curative but very effective at lowering PSA.

Now that we have Pylarify, we have a tool that should identify disease rather than risk. CT/Pylarify negative regardless of Gl, PSA…no XRT to nodes. We follow the “indication” for ADT, starting with Pelvic RT.

For post op PSA, Pylarify + pelvic prostate bed, 66 Gy. Wait to discern if PSA responds. If PSA does not go to zero, XRT or systemic disease. Add ADT then.

No one dies of PSA. ADT has adverse effects, costs, and can be held to treat symptomatic disease, what palliation’s goals of palliation.

I inform patients of my thoughts ...

My routine practice is to give ADT for at least 2-3 months prior to WPRT in patients with gross nodal disease with up to 3 years adjuvant therapy, and consideration of ARPI. It is demonstrated that 3-6 months ADT reduced nodal volume and that volume response is associated with improved disease control. Consensus guidelines recommend reducing nodal volume with neoadjuvant ADT to reduce high dose boost volumes and risk of treatment side effects. Studies demonstrating benefit to WPRT have used neoadjuvant ADT for 8-12 weeks, and also shown neo-adjuvant vs adjuvant ADT with WPRT is associated with better outcomes. The SANDSTORM meta-analysis showed neoadjuvant ADT with WPRT was at least equivalent to adjuvant, in contrast to prostate only where...