The advent of highly sensitive PSMA PET imaging identifies metastases in many patients previously considered to have only biochemical relapse (BCR). However, experts argue against a knee-jerk reaction to treat. Many of these patients, particularly those with slow PSA doubling times, can be safely observed, challenging the assumption that visible disease always requires immediate intervention.

Even within a single patient, tumor lesions exhibit significant heterogeneity in PSMA expression, with some being "hot" and others "not." This ensures that a standard dose of radioligand therapy will not be delivered uniformly across all disease sites, creating an inherent mechanism for resistance and incomplete response.

The future of advanced prostate cancer treatment is shifting towards therapies that target cell surface markers. This new era will be defined by a growing arsenal of radioligands, T-cell engaging bispecific antibodies (BiTEs), and antibody-drug conjugates (ADCs) aimed at targets like PSMA, B7-H3, and HK2.

Blocking the androgen receptor with enzalutamide can increase PSMA expression. In patients on enzalutamide alone, this predicts a poor outcome. However, for patients receiving combination therapy, this increased expression creates a better target for lutetium-PSMA, effectively mitigating the negative prognosis and improving survival.

An NCI working group coined "PSMA positive BCR" to classify patients with biochemical relapse (BCR) who have findings on a modern PSMA PET scan. This formally recognizes this group is distinct from both conventionally-defined metastatic patients and traditional BCR patients, necessitating unique clinical trial designs and treatment strategies.

In castration-resistant states, prostate cancer cells often amplify their androgen receptors (AR) to survive low testosterone levels. Bipolar androgen therapy exploits this by introducing a massive surge of testosterone. This "shocks" the over-amplified AR system, causing it to regress and disrupting downstream tumor growth pathways.

The NCI Working Group argues against equating PSMA PET-positive biochemically recurrent (BCR) prostate cancer with traditional metastatic disease. They propose the term "PSMA positive BCR" to emphasize that traditional prognostic factors still apply and the natural history is distinct and often more indolent.

New guidelines from an international working group are replacing patient-insensitive terms like "castration-resistant" with "Androgen Pathway Modulator (APM) resistant/naive." This modernizes language to encompass a broader range of therapies and improve patient communication, while also incorporating sensitive imaging like PSMA PET.

Even when an ARPI is no longer effective as a standalone therapy, continuing it may be beneficial. By maintaining pressure on the androgen receptor pathway, the drug can upregulate downstream targets like PSMA, potentially enhancing the efficacy of subsequent PSMA-targeted therapies like radioligands or ADCs.