Biology of Lung Cancer Metastases

Abstract

Non-small cell lung carcinoma (NSCLC) remains the leading cause of death from cancer in both men and women. Distant reoccurrence remains the major cause of morbidity and mortality in the patients with lung cancer. The term metastasis is defined as the transfer of disease from one organ to part or to another not directly connected to it. Metastasis is the primary clinical challenge as it is unpredictable in onset and it exponentially increases the clinical impact to the host. Tumor metastasis is a multistage process in which malignant cells spread from primary tumor to discontiguous organs. It involves a rest and growth in different micro-environments, which are treated clinically with different strategies depending on the tumor histotope and metastatic location. Some isolated metastases may be resected, whereas metastases to other organs may be treated with radioisotopes and are virtually unresectable. Because of the cellular heterogeneity therapies have varying degrees of efficacy that are challenging not only for the oncologist but also for our understanding of the metastatic process. This chapter will focus on differences regarding morphology and biomarker expression between the primary tumor and metastases of lung adenocarcinoma. The mutation status of metastases can differ from that of the primary tumor and also among metastases. The review will also present the frequency and the significance of pathologic variables between primary tumor and metastases.