Segmentectomy vs Lobectomy for 2 - 3cm IASLC Grade 1-2 Lung Adenocarcinoma: A Multi-center RCT

1. Initial Registration (1.1) Inclusion Criteria: 1. Aged 20 to 79 years, regardless ofgender. 2. Preoperative CT or PET-CT suggests: ① Imaging diameter of 2-3 cm.

• Suspicion of non-small cell lung cancer (NSCLC).
• Solitary nodule or concomitant lesions with microinvasion or below.
• Primary tumor not located in the middle lobe.
• No suspected lymph node involvement. 3. Preoperative CT lungwindow (window level -700HU, window width 1500HU) indicates thenodule is predominantly solid, i.e., the consolidation-to-tumorratio (CTR) is greater than 0.5 (CTR > 0.5).

4. Good lung function (FEV1 > 1.5 L or FEV1% ≥ 60%), tolerablefor both segmentectomy and lobectomy.
5. Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2. 6. Voluntary participation with signed informed consent,able to comply with study visit plans and other protocolrequirements.
6. No history of ipsilateral thoracotomy; video-thoracoscopicexamination meets the criteria.
7. No history of chemotherapy or radiotherapy, includingtreatment for other cancers. Eligible if more than 5 years havepassed since completion of perioperative adjuvant chemotherapy.Eligible if there is a history of or ongoing hormone therapy.
8. All the following laboratory test results are eligible (alllaboratory tests use the latest results within 28 days beforeinitial registration; laboratory tests on the same day within 4weeks before initial registration are allowed):

• White blood cell count ≥ 3000/mm³.

• Hemoglobin ≥ 8.0 g/dL (without blood transfusion within 28 days before initialregistration).

• Platelet count ≥ 10×10⁴/mm³.

• AST ≤ 100 IU/L. ⑤ ALT ≤ 100 IU/L. ⑥ Total bilirubin ≤ 2.0 mg/dL. ⑦ Serum creatinine ≤ 1.5 mg/dL. 10. The patient has signed a written

informed consent. (1.2) Exclusion Criteria:

1. Active bacterial or fungal infection (confirmed by imagingdiagnosis or bacteriological examination with fever >38°C).

2. Multiple active cancers (synchronous or metachronous multipleprimary cancers, excluding in situ carcinoma or intramucosalcancer lesions considered cured by local treatment; such lesionsare not included in active multiple cancers).

3. Patients with severe impairment of cardiac, hepatic, or renalfunction (cardiac function grade 3-4; ALT and/or AST more than 3times the upper limit of normal; Cr exceeding the upper limit ofnormal).

4. Patients with concomitant other malignant tumors orhematological diseases.

5. Pregnant, planning to become pregnant, or lactating femalepatients (diagnosed with early pregnancy when urine HCG >2500IU/L).

6. Any form of antitumor therapy before tumor resection, includinginterventional chemotherapy embolization, ablation,radiotherapy, chemotherapy, and molecular targeted therapy.

7. Patients who participated in other tumor-related clinical trialswithin the past three months.

8. Preoperative CT suggests ground-glass predominant nodules (CTR < 0.5).

9. Patients with positive lymph nodes indicated by preoperativeimaging or lymph node puncture (clinical N stage = 1 or 2).

10. Patients with tumors near the hilum who cannot undergosegmentectomy.

11. Patients deemed unsuitable for enrollment by the investigator.

12. Intraoperative Secondary Registration (2.1) Inclusion Criteria: 1. Intraoperativefrozen section indicates invasive lung adenocarcinoma with International Associationfor the Study of Lung Cancer (IASLC) grade 1-2 (<20% pathological high-gradesubtypes).

13. Intraoperative frozen section shows negative surgical margins. 3. Intraoperative exploration reveals no severe adhesions or lymph node inflammatory changes (adhesions of pulmonary vessels or bronchi), confirming feasibility for both lobectomy and segmentectomy.

(2.2) Exclusion Criteria:

1. Patients with IASLC grade 3 (≥20% pathological high-grade subtypes) indicated byintraoperative frozen section.

2. Patients confirmed with in situ carcinoma or microinvasive adenocarcinoma byintraoperative frozen section.

3. Patients with preoperative findings of distant metastasis or pleural/asciticeffusion.