mCRPC: Choosing Lu-177 PSMA or Cabazitaxel

What is this pathway about?

mCRPC means metastatic castration-resistant prostate cancer: cancer that has spread and is progressing despite testosterone being kept at a very low level. Lu-177 PSMA delivers radiation to cancer expressing the PSMA target. Cabazitaxel is a chemotherapy drug.

This infographic helps organise a discussion when both treatments are possible options. Its branches are a practical teaching framework; treatment eligibility and sequencing still require individual assessment.

How to follow the diagram

1. Start with the patient's overall condition

   Consider daily activity, symptoms, how quickly the cancer is progressing, previous treatments and the patient's priorities. A fitter patient may have the opportunity to receive several treatments in sequence. Frailty or rapidly progressing disease may limit those opportunities.

2. Check kidney function and blood counts

   Kidney function, urinary obstruction and bone-marrow reserve influence treatment safety. Blood counts help assess the ability to tolerate treatment. Reversible problems should be addressed, with specialist discussion when reserve is limited.

3. Look at PSMA uptake across the cancer sites

   Strong, fairly consistent PSMA uptake supports consideration of PSMA-targeted therapy. Mixed uptake means some sites express the target more strongly than others. Significant low-uptake or PSMA-negative disease may need a different systemic approach.

4. Use FDG PET when it can answer an additional question

   An FDG-positive but PSMA-negative lesion is active cancer without a clear PSMA target. This mismatch can signal disease that PSMA-targeted therapy may not adequately treat. FDG PET is useful in selected situations; it is not mandatory for every patient.

What do ES 0–3 mean?

The expression score compares tumour uptake with normal reference tissues on PSMA PET. Blood pool means activity in the blood; the parotid is a salivary gland near the ear.

The score describes imaging; it does not prescribe treatment. The team also considers lesion size, distribution, tracer characteristics, disease outside the PSMA-positive sites and treatment-specific eligibility criteria.

What does the supporting imaging review add?

Ranjan and colleagues review how imaging can support patient selection, response assessment and follow-up during Lu-177 PSMA therapy. PSMA PET/CT is central; FDG PET, post-treatment SPECT/CT and whole-body diffusion-weighted MRI can provide complementary information. Imaging findings should be interpreted alongside symptoms, blood tests and treatment history.

This is a critical review, rather than a new trial validating the supplied infographic. The authors also discuss imaging biomarkers and prediction models, while recognising the need for further validation.

For the direct treatment comparison, TheraP was a randomised phase II trial in selected patients. Lu-177 PSMA-617 produced more PSA responses than cabazitaxel, but longer follow-up found similar overall survival between the randomised groups. The diagram should therefore not be read as proof that one treatment always prolongs life more than the other.