RETAIN-2 Trial Results: Blood Test Accurately Predicts Metastatic Risk for Bladder Cancer Patients Seeking to Avoid Surgery

RETAIN-2 trial shows ctDNA blood tests predict metastatic risk in bladder cancer. Learn how chemoimmunotherapy allows some patients to safely skip surgery.

By: AXL Media

Published: Feb 27, 2026, 1:05 PM EST

Source: The information in this article was sourced from Temple University Health System

Advancing the Frontier of Bladder Preservation

A significant shift in the management of muscle-invasive bladder cancer (MIBC) is underway as clinical trial data confirms the utility of blood based biomarkers for treatment personalization. Presented at the 2026 ASCO Genitourinary Cancers Symposium, the RETAIN-2 trial has shown that a response adapted approach can allow select patients to preserve their bladder without compromising long term survival. This strategy focuses on neoadjuvant chemoimmunotherapy, which prepares the body to fight cancer cells before a final decision is made regarding the necessity of a radical cystectomy, a surgery that traditionally carries a high burden of complications and lifestyle changes.

The Role of ctDNA in Predicting Metastatic Spread

The cornerstone of this new diagnostic approach is the analysis of circulating tumor DNA (ctDNA), which are microscopic fragments shed by malignant cells into the bloodstream. Lead author Pooja Ghatalia, MD, reported that the absence of ctDNA following treatment serves as a powerful predictor of favorable outcomes. Specifically, patients who tested negative for these genetic fragments were significantly more likely to remain metastasis free after a two year period. This provides clinicians with a critical tool to identify individuals whose cancer has been successfully systemicized and who may not require the immediate removal of the bladder to prevent the spread of the disease.

Limitations in Detecting Local Recurrence

Despite its success in mapping metastatic risk, the study highlighted a critical limitation of current ctDNA technology. While the majority of the surveillance group remained free of distant cancer spread, 22 patients experienced a recurrence within the bladder itself. Crucially, 19 of those individuals did not show an increase in ctDNA levels at the time of their local recurrence. This finding underscores that while blood tests are excellent for monitoring systemic risk, they cannot yet replace traditional diagnostic methods, such as cystoscopy, for early detection of cancer returning to the local site.