In neoadjuvant settings, ctDNA monitoring allows for real-time therapy adjustment. Data from the iSpy platform shows 80% of hormone-positive patients clear ctDNA with half the chemotherapy, enabling de-escalation, while the remaining 20% can be identified for escalated treatment.

Data from trials like Niagara suggests a powerful new paradigm for assessing treatment success. Combining urine tumor DNA (uTDNA) for local disease and circulating tumor DNA (ctDNA) for systemic relapse offers a more dynamic view than traditional pathology and is poised to become the superior surrogate endpoint in bladder cancer trials.

Historically, discussing adjuvant therapy for Stage III colon cancer was quick and straightforward, while Stage II was complex. The advent of ctDNA testing has reversed this dynamic. Stage II decisions are now clearer (treat if positive), while Stage III discussions have become much longer and more nuanced as clinicians integrate ctDNA data with patient preferences.

Circulating tumor DNA (ctDNA) is a powerful biomarker for identifying high-risk bladder cancer patients. However, its imperfection presents a new clinical dilemma: with a ~12% relapse rate even in ctDNA-negative patients, clinicians must decide whether to withhold adjuvant therapy and accept that risk, or overtreat the 88% who are likely cured.

In adjuvant bladder cancer trials, ctDNA status is both prognostic and predictive. Patients with positive ctDNA after surgery are at high risk of relapse but benefit from immune checkpoint inhibitors. Conversely, ctDNA-negative patients have a lower risk and derive no benefit, making ctDNA a critical tool to avoid unnecessary, toxic therapy.

While circulating tumor DNA (ctDNA) is a powerful prognostic marker, it is not yet part of the formal "clinical complete response" definition for bladder-sparing trials. Experts lack data on its ability to predict the superficial, non-muscle invasive relapses common in this setting.

The InVigor11 study was the first to show that detecting recurrence via a ctDNA test before it's visible on scans is not just a prognostic sign, but an actionable clinical state. Intervening with therapy at this early stage was proven to improve patient outcomes, establishing a new paradigm for cancer surveillance.

High relapse rates (~70%) in surgery-alone arms of recent trials suggest most patients with muscle-invasive bladder cancer (MIBC) already have micrometastatic disease. This reframes the disease, prioritizing early systemic therapy over immediate surgery to achieve control and potential cure.

The success of new treatments like immunotherapy and ADCs leads to more patients achieving a deep response. This high efficacy makes patients question the necessity of a radical cystectomy, a life-altering surgery, creating an urgent need for data-driven, bladder-sparing protocols.