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 neoadjuvant accelerated methotrexate, vinblastine, doxorubicin, and cisplatin (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.