Stage I Non-Small Cell Lung Cancer: Recurrence Patterns, Prognostic Factors and Survival

Lung cancer is the leading cause of cancer-related death worldwide. Surgical resection is the treatment of choice for early-stage non-small cell lung cancer (NSCLC).1,2 Five-year survival in patients with resected stage I NSCLC ranges between 55% and 80%.3-6 Tumor recurrence is the most common cause of death, and thus the main obstacle for long-term survival after resection.4-10 The postoperative recurrence rates in stage I NSCLC range between 22% to 38%.4-8 The incidence of local or regional recurrence in stage I NSCLC after surgical resection has been reported between 7% to 15%,4-6 while distant metastasis been reported between 14% and 23%.4-8 Post-recurrence survival in resected stage I NSCLC is poor.7,10-12 The fifth edition of the TNM staging system for lung cancer was published in 1997, and stage I NSCLC was subdivided into IA (T1N0M0, tumor size ≤ 3 cm) and IB (T2N0M0, tumor size > 3 cm).3 In addition to tumor size greater than 3 cm, the T2 descriptor also includes tumors that invade the visceral pleura regardless of size, tumors that involve the main bronchus ≥ 2 cm distal to the carina, and tumors that result in associated atelectasis and obstructive pneumonitis that extends to the hilar region but does not involve the entire lung radiographically.3 In the sixth edition of the TNM classification (TNM 6)13 for lung cancer published in 2002, no change was made to the previous edition.3 The seventh edition of the TNM classification (TNM 7) for lung cancer has been published in 2009.14,15 The changes to the TNM 6 for lung cancer were based upon the proposals from the International Association for the Study of Lung Cancer (IASLC). In the seventh edition, T1 descriptor has been classified into T1a (≤ 2 cm) and T1b (> 2 to ≤ 3 cm), while size-based T2 descriptor has been classified into T2a (> 3 to ≤ 5 cm), T2b (> 5 to ≤ 7 cm), and T3 (> 7 cm).16 Stage I NSCLC was subdivided into IA (T1aN0M0, T1bN0M0) and IB (T2aN0M0).17 T2bN0M0 was reclassified as stage IIA.17 This review focuses on recurrence patterns of stage I NSCLC after surgical resection, survival after recurrence, and its prognostic factors. Predictors for local recurrence and distant metastasis are analyzed and discussed separately. Recent reports in the literature aiming at recurrence patterns and survival in stage I NSCLC (TNM 7) were also reviewed and included.