Radical radiotherapy and chemotherapy are the main treatment methods for locally advanced lung cancer. In recent years, research has shown that compared with simple radiotherapy and chemotherapy, the combination of radiotherapy and chemotherapy with consolidation immunotherapy (i.e. radical radiotherapy and chemotherapy) has increased the 5-year progression free survival rate of unresectable locally advanced non-small cell lung cancer patients by 14%, reduced the risk of tumor recurrence by nearly 50%, and become a new standard treatment mode. At the same time, this treatment model also brings new problems: 19% of patients are cured after radiotherapy and chemotherapy, and continuing immunotherapy does not bring survival benefits, but instead increases the adverse reactions and economic burden of patients. Recently, Professor Wu Yilong's team from Guangdong Provincial People's Hospital proposed the concept of "early MRD clearance during radiotherapy" for the first time, and confirmed that early MRD clearance for lung cancer has a better prognosis and may not require long-term consolidation immunotherapy. The relevant results were recently published in the international medical journal Cancer Cells. MRD, also known as molecular residual lesions, refers to the discovery of mutated molecular signals from cancer sources during high-depth genetic testing of peripheral blood. In 2019, under the leadership of Wu Yilong, the Guangdong Provincial Institute of Lung Cancer designed a "trilogy" of lung cancer MRD including early and mid-term surgery, local advanced radiotherapy and chemotherapy, and advanced systemic treatment, establishing a ctDNA-MRD detection technology framework. Wu Yilong's team found in previous studies on early to mid stage lung cancer postoperative patients that if the patient consistently maintains negative MRD after surgery, it is a potential cure population, which has been further confirmed in this study. Research has shown that only 2 out of the locally advanced patients who remain MRD negative after radiotherapy and chemotherapy have experienced tumor recurrence, with a 2-year progression free survival rate of 88.4%. Wu Yilong's team first proposed the concept of "early MRD clearing during radiotherapy", which is an important breakthrough in the clinical application of MRD for locally advanced lung cancer. Through MRD testing, it is possible to accurately distinguish which patients need to continue immunotherapy after radiotherapy and chemotherapy, and which patients do not. This is the biggest significance of research. "Zhou Qing, the director of the Cancer Hospital of Guangdong Provincial People's Hospital, said that for patients who do not need to continue immunotherapy, if tumor cells are excessively hit, it may actually lead to drug resistance and tumor recurrence. Previously, we could only rely on reviewing data to 'tell fortune' and telling patients that 'there is a 20% chance of cure after radiotherapy and chemotherapy'. Now we can clarify whether each patient has been cured after radiotherapy and chemotherapy without immunotherapy or needs immune consolidation, "said Wu Yilong. It is reported that the Guangdong Provincial Institute of Lung Cancer is currently conducting a real-world study to further validate the above research results and gradually apply them to clinical treatment, benefiting more patients. Science and Technology Daily reporter Ye Qing, correspondent Hao Li, Zhang Lanxi (Xinhua News Agency)