NeoCOAST-2 Trial Shows Early ctDNA Clearance Predicts Lung Cancer Survival

Traditionally, oncologists wait until a lung cancer tumor is surgically removed to examine its tissue and determine if preoperative chemotherapy actually worked. But a new approach flips that timeline, using a simple blood test to track microscopic tumor DNA as it vanishes from the bloodstream weeks before the patient ever reaches the operating room.[1][2]

The findings, presented at the European Society for Medical Oncology 2026 Congress and published simultaneously in the journal Nature, stem from the Phase II NeoCOAST-2 trial. Researchers demonstrated that clearing circulating tumor DNA early in treatment strongly predicts long-term survival in early-stage lung cancer.[1][2]

Led by investigators at The University of Texas MD Anderson Cancer Center, the global platform trial evaluated patients with resectable Stage IIA to Stage IIIA non-small cell lung cancer. The study tested novel perioperative regimens built around AstraZeneca’s immunotherapy drug Imfinzi, administered both before and after surgery.[1][4]

The oncology congress served as a major showcase for this shifting paradigm, with AstraZeneca presenting more than 100 abstracts across its clinical portfolio. The NeoCOAST-2 data emerged as a highlight, underscoring the pharmaceutical giant's push to integrate precision biomarkers into its drug development pipeline.[2][5]

Tracking The Invisible

Instead of relying solely on imaging scans, the research team utilized an ultrasensitive, methylation-based blood assay. As cancer cells die during treatment, they shed fragmented genetic material into the bloodstream, which the assay detects and quantifies as a real-time measure of tumor burden.[1][3]

The trial paired Imfinzi with several experimental agents, including the antibody-drug conjugate Datroway, as well as oleclumab and monalizumab. Patients received these combinations as neoadjuvant therapy, which is treatment designed to shrink the tumor and eliminate microscopic spread before surgical resection.[2][4]

Datroway works by targeting specific proteins on the surface of cancer cells and delivering a toxic payload directly inside them. When combined with Imfinzi, which strips away the tumor's ability to hide from the immune system, the dual approach aims to overwhelm the cancer's defenses.[1][2]

The methylation-based assay used in the trial represents a significant technical leap over older sequencing methods. Rather than just looking for specific genetic mutations, it detects distinct chemical tags on the DNA that are unique to cancer, allowing it to find tumor fragments even when mutation levels are extremely low.[3]

Researchers found that patients whose blood was cleared of circulating tumor DNA early in the neoadjuvant phase experienced significantly better clinical outcomes. This early molecular clearance was tightly linked to a lower risk of the cancer recurring after surgery.[1][3]

A Complementary Picture

"While pathologic response has become an important measure of treatment benefit, ctDNA can provide an earlier view of how a patient's cancer is responding," said Dr. Tina Cascone. The MD Anderson professor of thoracic medical oncology served as the trial's lead investigator.[1]

The Datroway-containing regimen proved particularly effective, demonstrating the highest rates of both early molecular clearance and pathologic complete response. A pathologic complete response means no active cancer cells are found in the lung tissue removed during surgery.[2][3]

However, the study revealed that blood tests and tissue pathology provide distinct, complementary pieces of information. While a tissue biopsy confirms that the local tumor in the lung has been eradicated, a clear blood test suggests that the cancer has been eliminated systemically across the entire body.[3]

Patients who achieved both milestones—a pathologic complete response at surgery and complete molecular clearance from their bloodstream—experienced the most favorable long-term outcomes of anyone in the trial. Their risk of disease-related events dropped dramatically compared to those who missed one or both marks.[1][3]

The discordance between the two measures is particularly revealing for oncologists. Some patients achieved local tumor clearance in the lung but still had detectable tumor DNA in their blood, indicating hidden microscopic disease elsewhere that could drive a future relapse.[3]

Reshaping Lung Cancer Care

Conversely, other patients cleared their blood of tumor DNA but still had residual cancer cells in the surgically removed lung tissue. By combining both metrics, doctors can build a much more accurate risk profile for each individual patient.[3]

The trial also monitored patients after their operations, finding that post-surgical clearance remained a powerful prognostic tool. According to the Nature publication, molecular clearance following surgery occurred in 107 of 115 evaluated patients, representing 93 percent of the cohort.[3]

Patients who maintained clear blood tests after surgery had numerically longer event-free survival. Among those 107 patients with post-surgical clearance, disease recurrence occurred in just seven individuals, or 6.5 percent, compared to a near-certain relapse for those who never cleared the markers.[3]

For patients with resectable non-small cell lung cancer, these insights address a critical vulnerability in current treatment protocols. Even when caught early and removed surgically, lung cancer frequently returns because undetectable microscopic metastases survive the initial intervention.[1][4]

By identifying which patients are responding to neoadjuvant therapy in real time, oncologists could eventually adapt treatments on the fly. A patient whose blood markers do not clear might be switched to a more aggressive regimen before surgery, rather than waiting months to discover the initial drug failed.[1][3]

The Future Of Monitoring

"These findings suggest ctDNA clearance may help identify patients most likely to achieve long-term benefits," Dr. Cascone noted during the presentation. She added that the metric could play an important role in guiding future perioperative treatment strategies.[1]

The trial results reflect a broader shift in oncology toward blood-based monitoring of molecular residual disease. As these assays become more sensitive, they are poised to replace lagging indicators with real-time biological feedback across multiple types of solid tumors.[1][3]

Ultimately, the ability to track tumor DNA clearance could redefine the boundaries of surgical oncology. If a blood test can definitively prove that systemic therapy has eradicated the cancer, some patients might one day safely avoid invasive lung surgery altogether.[1][3]