The CCTG PR21 trial revealed a paradox: while Lutetium achieved a much higher PSA response rate than docetaxel chemotherapy, overall survival was better for patients who received docetaxel first. This counter-intuitive finding complicates treatment sequencing and challenges the assumption that higher initial response equals better long-term outcomes.

The investigator-led PLUTO trial found docetaxel chemotherapy provided a better overall survival benefit than lutetium in first-line mCRPC. This result directly confronts the common clinical bias against chemotherapy ("chemophobia"), proving that older treatments can still outperform newer targeted agents and should not be prematurely abandoned.

A key hypothesis for why docetaxel showed better overall survival than lutetium in the PLUTO trial is that patients treated with lutetium upfront may become unfit for subsequent chemotherapy. This highlights a critical factor in trial design: the planned therapeutic sequence and a patient's ability to receive later-line treatments significantly impact survival outcomes.

Experts admit to preferring docetaxel chemotherapy over lutetium for symptomatic mCRPC patients primarily because it 'feels' more aggressive and is logistically faster to administer. This decision is based on perception and convenience rather than strong clinical evidence comparing the agents in this specific context.

PSMA-PET imaging at baseline can identify who benefits from adding lutetium-PSMA. In the ENZA-P trial, patients with high-volume disease saw a significant survival benefit from the combination. Conversely, those with low-volume disease derived no benefit, suggesting imaging can be used for patient selection.

The CCTG PR21 trial revealed a paradox: patients treated with lutetium first had a PSA response rate double that of docetaxel chemotherapy. However, overall survival was better for the group that received docetaxel first. This highlights the complexity of sequencing and suggests initial response isn't always predictive of long-term outcomes.

Despite his study showing an overall survival signal favoring docetaxel, lead author Dr. Kim Chi attributes this to crossover bias where patients avoided chemotherapy. He personally favors lutetium first due to its superior tolerability, contradicting the panel's majority opinion.

The PR21 trial showed better overall survival for docetaxel followed by Lutetium, despite similar progression-free survival. The likely reason is not drug superiority but patient behavior: a higher percentage of patients complete the second therapy when starting with chemo, highlighting how treatment fatigue significantly impacts survival.

While Lutetium shows promise in hormone-sensitive prostate cancer, experts raise concerns about potential late-effect toxicities for patients surviving many years. This contrasts with docetaxel, where toxicity is acute and resolves after treatment, highlighting an unknown long-term risk-benefit profile for new radioligand therapies.