How do you interpret isolated PSMA-avid sites in a patient with prostate cancer with no pelvic or RP LN uptake?

The issue of false-positive PSMA scans is a vexed one, and we are still learning how to handle this optimally. My general approach is to think about the clinical context, level of risk, and whether an early diagnostic pick-up will actually make a clinical difference.

For example, in a patient with ...

There are many reports of false-positive PSMA lesions, such as in sympathetic ganglia incorrectly called positive nodes, in bone (e.g., rib lesion without other sites of disease), in the previously irradiated prostate, and in other conditions too. Here are some representative papers with good pictur...

There's no rule that prostate cancer (or any cancer) has to involve lymph nodes before other metastatic disease. Bone-only metastatic disease is exceedingly common early in the course of mCSPC.

Be wary of other mimics with high native PSMA expression. The following paper is a good review:

de Galiza Ba...

Ordering studies in low-risk populations or in situations where substantial changes in treatment are unlikely can lead to a cascade of patient anxiety, physician work, and higher health care costs.

For high-risk patients, the proPSMA phase 3 data support advanced imaging modalities over CT and bone s...