Chemotherapeutic issues in the management of unresectable stage III non-small cell lung cancer

The standard of care in unresectable stage IIIA/B non-small cell lung cancer is combined-modality therapy using both chemotherapy and thoracic radiation therapy. Although there is general agreement on this principle, there remain many controversies regarding the optimal combined-modality approach in this patient population. Both induction and concurrent chemoradiotherapy strategies were initially tested, with both approaches improving survival in randomized phase III trials. Several trials have now been completed comparing sequential versus concurrent approaches. There appears to be a modest and consistent advantage to the concurrent approach at the risk of an increase in the rates of acute toxicities, particularly esophagitis and myelosuppression. The concurrent approach used in the phase III trials evaluating the question of sequence has been the use of full-dose systemic chemotherapy rather than a low-dose radio-enhancing strategy. These approaches are distinctly different, and one must recognize this difference when evaluating results from clinical trials. A number of clinical trials have established the use of both induction and consolidation chemotherapy; however, the optimal approach remains unclear. What is clear is that this population of patients needs aggressive therapy directed at achieving locoregional control as well as control of occult micrometastatic disease that is present in the majority of cases. As treatment strategies have become more aggressive, survival outcomes have improved, although the differences have been modest at best, and the risk of severe toxicity has increased. Future aggressive approaches must enhance both locoregional and distant control of occult disease, with acceptable rates of both acute and long-term toxicities.