ctDNA Predicts Bladder Cancer Metastasis, Not Local Recurrence

For some patients diagnosed with muscle-invasive bladder cancer, a new blood test may offer a path away from the operating room. Researchers at Fox Chase Cancer Center have found that detecting circulating tumor DNA, or ctDNA, in the bloodstream can help predict which individuals are at lower risk of their cancer spreading – and therefore might safely avoid radical cystectomy, the complete removal of the bladder. This development, presented today, offers a potential refinement to treatment strategies, moving towards more personalized care for a challenging cancer.

Understanding ctDNA and Muscle-Invasive Bladder Cancer

Muscle-invasive bladder cancer (MIBC) is an aggressive form of the disease where the cancer has grown into the muscle layer of the bladder wall. Standard treatment often involves radical cystectomy, alongside chemotherapy. However, this surgery is a major undertaking, carrying significant risks and impacting quality of life. The goal is always to eliminate the cancer, but for some patients, the potential benefits of surgery may be outweighed by the burdens. Here’s where the promise of ctDNA analysis lies.

ctDNA refers to fragments of DNA released into the bloodstream by cancer cells. Detecting these fragments can indicate the presence of cancer, and changes in ctDNA levels can reflect how the cancer is responding to treatment. The Fox Chase Cancer Center research focused on whether ctDNA levels could predict which patients, undergoing bladder-sparing treatment (chemotherapy and radiation), were at low enough risk of metastasis – the spread of cancer to other parts of the body – to potentially avoid surgery. Fox Chase Cancer Center led this investigation.

What the Research Showed: Predicting Metastasis, Not Local Recurrence

The study found that ctDNA can predict metastatic risk in patients receiving bladder-sparing treatment. In other words, if ctDNA was detected after treatment, it signaled a higher likelihood of the cancer spreading. However, crucially, the researchers also discovered that ctDNA was not a reliable indicator of whether the cancer would return within the bladder itself – a phenomenon known as local recurrence. This distinction is important because local recurrence can often be treated with further localized therapies.

So the test isn’t a universal “pass” or “fail” for surgery. It specifically addresses the risk of distant spread, which is the most life-threatening aspect of bladder cancer. The findings suggest that patients with negative ctDNA results after treatment may be able to safely forgo cystectomy, while those with positive results would likely benefit from surgery. Further research is needed to refine this approach and determine the optimal timing and frequency of ctDNA testing.

The RETAIN Trials and Ongoing Investigation

The research builds on earlier work from the RETAIN trials, which explored the use of ctDNA monitoring in bladder cancer. Pooja Ghatalia, MD, of Urology Times, has shared new insights from these trials, emphasizing the evolving role of ctDNA in guiding treatment decisions. The RETAIN trials are designed to identify biomarkers, like ctDNA, that can help personalize treatment and improve outcomes for bladder cancer patients.

Who Does This Affect?

These findings primarily impact individuals newly diagnosed with muscle-invasive bladder cancer who are considering bladder-sparing treatment. Currently, the decision to proceed with or without cystectomy is often based on factors like tumor stage, grade, and the patient’s overall health. The addition of ctDNA analysis could provide a more objective measure of risk, helping patients and their doctors make more informed choices. It’s important to note that this test is not yet standard practice and is currently being investigated in clinical trials.

Limitations and What the Research Doesn’t Tell Us

While promising, this research has limitations. The study focused on patients receiving specific bladder-sparing treatments. It’s unclear whether the findings would apply to all patients with MIBC or to those undergoing different treatment regimens. The study did not follow patients for a long enough period to determine the long-term impact of ctDNA-guided treatment decisions. It’s also crucial to remember that ctDNA analysis is not perfect; false negatives (missing ctDNA when cancer is present) and false positives (detecting ctDNA when cancer is not present) can occur. The research also doesn’t address the cost-effectiveness of ctDNA testing or its accessibility to all patients.

The Broader Context of Bladder Cancer Treatment

Bladder cancer affects approximately 80,000 people in the United States each year, according to the American Cancer Society. While most bladder cancers are diagnosed at an early stage, MIBC is a particularly aggressive form of the disease with a high risk of recurrence and metastasis. Radical cystectomy remains the gold standard treatment for MIBC, but it is a major surgery with potential complications, including urinary dysfunction, sexual dysfunction, and the need for urinary diversion. The development of less invasive treatment options, guided by biomarkers like ctDNA, is a major goal of bladder cancer research.

What Comes Next: Refining the Approach and Expanding Research

The next steps involve further validation of these findings in larger, multi-center clinical trials. Researchers are working to refine the ctDNA testing process, optimize the timing of testing, and identify other biomarkers that can complement ctDNA analysis. The goal is to develop a comprehensive risk assessment tool that can accurately predict which patients will benefit from surgery and which can safely avoid it. Ongoing research is also exploring the potential of ctDNA to monitor treatment response and detect early signs of recurrence. This work aims to personalize bladder cancer treatment, improving outcomes and quality of life for patients.