Induction and Concurrent Chemoradiation Therapy for Stage IIIA/B NSCLC The use of combined modality has become the standard of care in unresectable Stage IIIA/B non-small cell lung cancer (NSCLC). In the curative approach to this disease, both local control and eradication of occult micrometastatic disease must be achieved. Combined-modality trials employing induction chemotherapy have suggested a reduction in the rate of metastatic disease, suggesting that effectively delivered chemotherapy can eradicate occult micrometastatic disease. All of the trials cited have shown improved survival for the combined-modality arm. Combined-modality trials employing concurrent chemoradiation have suggested improved loco-regional control resulting in improved survival. These data suggest that both induction and concurrent treatment may be important and may exert their benefit in different manners: induction therapy with effective chemotherapy reduces the rate of overt metastatic disease, while concurrent treatment improves local control by enhancing the local effect of TRT. Four trials to date have been published addressing sequential versus concurrent therapy. In these trials, concurrent treatment yielded improved survival over the sequential approach. The value of either induction or consolidation therapy in addition to concurrent chemotherapy is currently being addressed in randomized Phase III trials.