Blood Test Predicts Bladder Cancer Treatment Success, Potential to Avoid Surgery
New data presented by researchers at Fox Chase Cancer Center suggests that a blood test analyzing circulating tumor DNA (ctDNA) can predict which patients with muscle-invasive bladder cancer (MIBC) may safely avoid surgery after undergoing chemoimmunotherapy. The findings, presented at the 2026 ASCO Genitourinary Cancers Symposium, offer a potential pathway toward bladder-sparing treatment for more patients.
ctDNA as a Predictor of Metastatic Risk
The study, an integrated analysis of the RETAIN trials, revealed that the presence of ctDNA after treatment was strongly associated with an increased risk of metastasis. Conversely, the absence of ctDNA predicted favorable outcomes, regardless of whether patients ultimately underwent cystectomy (bladder removal) or pursued active surveillance. Circulating tumor DNA comprises fragments of DNA shed into the bloodstream by cancer cells.
“This tells us ctDNA can be incorporated into the decision-making of who should keep their bladder and who should not, knowing that we also need additional tests or biomarkers to detect local recurrence early in patients who undergo active surveillance,” said Dr. Pooja Ghatalia, an Associate Professor in the Department of Hematology/Oncology at Fox Chase Cancer Center and first author of the study. Urology Times
RETAIN-2 Trial Results: A Response-Adapted Approach
The RETAIN-2 clinical trial demonstrated that a response-adapted bladder-preservation approach, utilizing neoadjuvant chemoimmunotherapy, can be considered for select patients. More than 70 patients with MIBC received a combination of chemotherapy and nivolumab, an immunotherapy drug. Those who achieved a complete response were entered into active surveillance rather than immediate surgery, and 80% remained metastasis-free after two years. ScienMag
Limitations: ctDNA and Local Recurrence
While ctDNA effectively predicted metastatic risk, the study found it was not a reliable indicator of local recurrence within the bladder. Of the 22 patients who experienced a recurrence of cancer within their bladder during surveillance, 19 did not show an increase in ctDNA levels.
The Importance of Bladder Preservation
Preserving bladder function is a significant goal for patients with bladder cancer, as bladder removal often leads to complications and a reduced quality of life due to the need for lifelong urinary diversion. ScienMag
Future Directions
Researchers will continue to follow patients from the RETAIN-2 trial for five years to assess the long-term outcomes of bladder-sparing treatment. They are also designing the RETAIN-3 clinical trial, which will incorporate ctDNA as a predictive biomarker in treatment decision-making. Urology Times
Dr. Ghatalia is a medical oncologist at Fox Chase Cancer Center in Philadelphia, Pennsylvania, and specializes in genitourinary cancers, including kidney, prostate, bladder, penile, adrenal, and testicular cancer. Fox Chase Cancer Center, Castle Connolly