Reclassification of early stage pulmonary adenocarcinoma and its consequences

Lung cancer is still the leading cause of death in the United States compared with other types of malignancies. Over the years, a change in the frequency of the two most common histological subtypes—adenocarcinoma and squamous cell carcinoma—has seen adenocarcinoma emerge as the most common form of lung cancer (1). The relatively poor prognosis for these tumors reflected in a 5-year survival rate estimated at 15.6% makes early detection and the development of new treatment strategies even more crucial (2). In this context it is not only becoming increasingly important to recognize tumors early in their course but also to separate tumors that are likely to behave more indolently from those with more aggressive behavior