Purpose: Although standard treatment of stage I non-small-cell lung cancer (NSCLC) consists of surgical resection alone, approximately 50% of clinical stage I and 30% to 40% of pathologic stage I patients have disease recurrence and die following curative resection. A large number of traditional pathologic and newer molecular markers have been identified, which appear to have important prognostic significance in this population. This review attempts to summarize these data comprehensively.
Methods: Criteria for study selection were English-language reports, identified using Medline and Cancerline, through the fall of 1994. Abstracts from the American Society of Clinical Oncology (ASCO) and the International Association for the Study of Lung Cancer (IASLG) were also reviewed.
Results: Molecular markers are classified as molecular genetic markers, differentiation markers, proliferation markers, and markers of metastatic propensity. A number of these markers have been reported to be highly predictive of outcome in stage I NSCLC, and several reports conclude that a specific biomarker may be, aside from clinical stage, the most powerful determinant of prognosis in NSCLC. However, little has been done to clarify the relationships between these newer biologic markers, classic clinicopathologic variables, and clinical outcome.
Conclusion: At present, a firm conclusion regarding which biomarkers are most important in predicting outcome is not possible, and a model that reliably integrates all independent prognostic variables cannot be developed. A prospective trial is mandatory to address this issue, and a study design is suggested that would facilitate the development of a prognostic index, while simultaneously asking a therapeutic question. The development of a prognostic index would facilitate future trials in which only high-risk stage I patients could be targeted for investigation of postresection adjuvant treatment strategies.