A blood test that can determine if you need more treatment after bladder cancer surgery

Roughly 40% of patients with muscle-invasive bladder cancer (MIBC) undergo a radical cystectomy.This procedure is more colloquially known as bladder removal surgery. After the surgery, patients may wonder: “Is the cancer really gone, or do I need more treatment just in case?” Until recently, doctors determined post-surgery treatment plans using traditional risk factors such as tumor stage. Now, a new tool can help answer that question more directly: a personalized blood test that looks for traces of cancer DNA circulating in your bloodstream.

On May 15, 2026, the FDA approved atezolizumab (Tecentriq) and atezolizumab and hyaluronidase-tqjs (Tecentriq Hybreza) as adjuvant (after-surgery) treatment for adults with MIBC who test positive for circulating tumor DNA (ctDNA) following cystectomy. Alongside it, the FDA approved Signatera CDx, a companion blood test made by Natera, to identify which patients actually need the extra treatment.

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How does the test work?

Signatera is a personalized blood test that searches for ctDNA that is unique to your own cancer. It can pick up signs of residual disease long before anything would show up on a CT scan or other imaging. According to Dana-Farber Cancer Institute’s Dr. Joaquim Bellmunt, who co-led the pivotal research behind this approval, the test is “detecting minimal residual disease and can identify patients who still have bladder cancer after surgery and might benefit from receiving atezolizumab.”

Patients are tested repeatedly during the year after surgery, starting about six weeks after the operation. If the test comes back positive at any point, it signals that microscopic cancer cells may still be present even if scans look clean.

The trial behind the approval: IMvigor011

The approval is based on results from IMvigor011 (NCT04660344), a phase 3, randomized, double-blind, placebo-controlled trial presented by Dr. Thomas Powles at the 2025 ESMO Congress in Berlin. Researchers screened 761 patients who had undergone radical cystectomy with lymph node dissection, then enrolled the 250 patients who tested ctDNA-positive during the 12 months after surgery. Those patients were randomly assigned, in a 2:1 ratio, to receive either atezolizumab or a placebo by IV infusion every four weeks for up to a year.

The results showed the promise of the approach:

• Disease-free survival: Patients who received atezolizumab went a median of 9.9 months without their cancer returning, compared with just 4.8 months on placebo, a 36% reduction in the risk of recurrence, as reported by the Oncology Nursing Society.
• Overall survival: Patients on atezolizumab also lived significantly longer overall, a median of 32.8 months versus 21.1 months on placebo, according to OncLive’s coverage of the data.
• Consistent benefit: The benefit held up whether ctDNA was detected right after surgery or emerged later during the monitoring period.

Just as important, patients who tested ctDNA-negative and were simply monitored without receiving any additional drug therapy did well. About 89% remained disease-free and more than 90% were still alive at a follow-up of nearly two years, as Dana-Farber’s research summary notes. That means many patients can safely avoid unnecessary treatment and its side effects.

Why this approach is a big deal

IMvigor011 was the first phase 3 study to demonstrate that using ctDNA can determine who will derive a survival benefit from adjuvant immunotherapy. It’s significant because providers no longer treat all high-risk patients the same way. Any detectable evidence of remaining cancer changes the treatment discussion. Instead of guessing who might benefit from more treatment, doctors can now use a blood test to find out.

What this means for you

If you’ve had a cystectomy or are going to have for MIBC, it’s worth asking your care team:

• Am I a candidate for ctDNA (Signatera) testing after my surgery?
• If I test positive, what would adjuvant atezolizumab involve, and what side effects should I watch for?
• If I test negative, how often will I be retested, and for how long?

Immune-related side effects are possible with atezolizumab, so your oncology team will monitor you closely throughout treatment.

This article is for informational purposes only and is not a substitute for professional medical advice. Talk with your oncologist about whether ctDNA testing and adjuvant immunotherapy are right for your specific situation. You can connect with other patients navigating MIBC via the Outcomes4Me Community.