Introduction: The importance of non-small cell lung cancer (NSCLC) histologic subtype has increased during the last few decades because of an unprecedented shift in epidemiology and an increasing number of target-specific chemotherapeutic agents. This review examined histology as a potential prognostic and/or predictive factor of clinical outcomes in advanced NSCLC.
Methods: Literature searches of articles from 1982 to 2007 were conducted. We identified publications detailing phase II or III studies, retrospective analyses, and meta-analyses that reported a statistically significant prognostic or predictive role for histology.
Results: Of 408 publications identified, 11 reported a prognostic association between histology and clinical outcomes, and 7 suggested that histologic subtype was predictive of outcomes in patients with advanced NSCLC treated with specific cytotoxic chemotherapy regimens. Fourteen publications reported histology was prognostic and/or predictive in patients treated with epidermal growth factor receptor inhibitors. Inadequate data collection, test methodology, or study design-including insufficient sample size, misclassified samples, and grouping of histologic subtypes for analysis-may have obscured the interpretation of the role of histology in many of the studies.
Conclusions: Although differences in study design and analyses make definitive conclusions difficult, evidence suggests that histology may be prognostic or predictive of clinical efficacy outcomes. To determine which patients would benefit from specific treatments and to further understand the role of histology, future studies should focus on establishing a definitive histologic diagnosis, and should include an analysis of histologic subtypes and efficacy outcomes.