Delayed Systemic Therapy Following Destructive Local Treatment of Pulmonary Oligometastases After No Evidence of Disease (NED) in Colorectal Cancer.

Inclusion Criteria

• •Patients with a pathologically confirmed diagnosis of colorectal cancer with the following disease conditions:
• •1. The patient has achieved No Evidence of Disease (NED) after undergoing EMR, surgery, radiofrequency ablation, or radiotherapy.
• •2. NED has been maintained for ≥ 6 months.
• •3. The patient has not received chemotherapy, or has only received postoperative adjuvant chemotherapy or first-line systemic therapy.
• •4. Oligometastatic lung lesions (defined as 5 or fewer lesions) detected after ≥ 6 months of NED maintenance, eligible for destructive therapy.
• •5. No prior radiotherapy to the lungs.
• •RECIST 1.1 criteria: The patient must have measurable lesions, defined as at least one nodal lesion with a longest diameter \> 1.5 cm, or at least one nodal lesion \> 1 cm with an accurately measurable pendulous diameter.
• •ECOG performance status: ≤ 2 (Eastern Cooperative Oncology Group general condition score).
• •The patient's expected survival must be ≥ 3 months.
• •Adequate hematologic function: Absolute neutrophil count ≥ 1.6 x 10⁹/L, with no growth factor support for at least 7 days prior to testing.
• •Normal organ function: The patient must be able to tolerate at least one of the local destructive treatments, as assessed by the corresponding department's physician, based on normal hepatic, renal, pulmonary, and cardiac function.
• •Reproductive age: Female patients of childbearing potential must agree to use a reliable method of contraception with their partner from the time of informed consent until 1 year after treatment completion.
• •The patient must have voluntarily provided informed consent to participate in the study.