Critical analysis of neoadjuvant therapy for Stage IIIa non-small cell lung cancer [corrected] [published erratum appears in Am Rev Respir Dis 1991 Jun;143(6):1473] Lung cancer is the major cause of cancer mortality. Locally advanced (Stage III) disease constitutes 30 to 40% of the entire group of non-small cell lung cancer (NSCLC). Surgical resection offers the best opportunity for cure, but resection of disease is possible in only a minority of patients with Stage IIIa disease. Even among patients who have "successful" surgery systemic relapse is common, and the 5-yr survival after complete resection is only 30%. Preoperative (neoadjuvant) chemotherapy is under investigation in an attempt to improve the bleak outcome of patients with Stage IIIa NSCLC. Preliminary trials have shown that this approach is feasible: neoadjuvant treatment can be administered with moderate toxicity and in most cases without compromising the possibility for surgical resection. In some instances, neoadjuvant treatment has produced pathologic complete responses, and in others it has decreased tumor bulk so that inoperable patients became surgical candidates. Whether this latter phenomenon has an impact on survival is unknown. Therefore, the role of neoadjuvant treatment for locally advanced lung cancer will not be known until properly designed randomized trials are conducted. 