Dr Pooja Ghatalia speks to ecancer about the phase II RETAIN-1 and RETAIN-2 trials.

These trials evaluated response-adapted strategies for muscle-invasive bladder cancer (MIBC) to identify patients eligible for cystectomy-sparing active surveillance after neoadjuvant therapy.

RETAIN-2 enrolled patients treated with AMVAC plus nivolumab, with those achieving clinical complete response and multiple tumour mutations entering active surveillance.

Most patients remained metastasis-free, with a large proportion retaining an intact bladder.

Integrated ctDNA analysis revealed that post-treatment ctDNA negativity or clearance strongly predicted lower metastatic recurrence risk, although ctDNA did not reliably predict local-only bladder recurrences.

These findings support the feasibility of bladder-preserving strategies while highlighting ctDNA as a valuable tool for identifying patients at low risk of metastatic progression.