Anti-tumor immune response in early stage non small cell lung cancer (NSCLC): implications for adjuvant therapy

The demonstration that systemic chemotherapy improves survival in patients who have had resection of early stage non-small cell lung cancer (NSCLC) represents a significant advance. The absolute benefit of adjuvant chemotherapy in this setting is small with an overall survival improvement of 5%. In addition, there are many patients who have contraindications to cisplatin-based adjuvant therapy. Adjuvant chemotherapy is intended to target systemic micrometastases that remain after primary resection. The observation that cancers can relapse months or years after initial surgery implies that the residual micrometastases exist in a latent or dormant state. The concept of tumor dormancy offers therapeutic potential through induction or maintenance of the dormant state in disseminated tumor cells or through eradication of these dormant cells. Cancer dormancy is a complex process with multiple potential mechanisms. This review will focus on some of the evidence for immune related tumor dormancy and the potential for immune therapies to improve outcomes in the adjuvant setting in NSCLC.