Treatment of Early-Stage (Stage I and II) Non-Small Cell Lung Cancer

Lung cancer remains the leading cause of cancer-related mortality worldwide. The TNM classification system is used to stage lung cancer, and according to the eighth edition of AJCC, early stage non-small cell lung cancer (NSCLC) includes malignancies that are classified as stage IA (T1miN0M0 or T1N0M0), IB (T2aN0M0), IIA (T2bN0M0), and IIB (T1-2N0M0 or T3N0M0). The treatment of choice for early-stage NSCLC in patients who are deemed eligible for surgery involves resection of the tumor. The eligibility for surgery is determined based on the patient’s functional capacity and pulmonary function tests. The extent of the pulmonary resection is determined by the location and size of the tumor. Lobectomy is still considered the mainstay surgical treatment for early-stage NSCLC, with pneumonectomy and sleeve resection being considered when tumor location and size require it. Interestingly, contemporary evidence suggests that segmentectomy might offer equivalent outcomes in terms of overall survival compared to lobectomy for <2 cm tumors. The benefit of adjuvant chemotherapy in early-stage lung cancer is controversial. It is currently recommended in patients with stage II NSCLC that have negative surgical margins and is optional in high-risk histology with stage IB NSCLC. Stereotactic body radiotherapy (SBRT) is considered an alternative definitive treatment for NSCLC, and it is typically utilized in patients who were not deemed eligible for surgery or who elect to undergo nonoperative management. Overall, patients with early-stage NSCLC have encouraging 5-year overall survival outcomes ranging from 92 to 53% depending on the stage of the disease.