Considerations about tumor size as a factor of prognosis in NSCLC.

A literature review of the initial attempt to correlate tumor size in NSCLC with the expectancy of survival is presented starting from the 60s. The larger size was connected with an increased risk of metastatic diffusion. In the 70s resulted evident the relationship between tumor size and lymph node involvement so affecting survival. In the context of the TNM Staging System (Mountain 1986) size appeared a well assessed factor of prognosis and is recognised to play a major role in Stage I where the subsets T1N0 and T2N0 showed a consistent difference in survival across the 3 cm cut-off. The peculiar relation between largest size and mediastinal lymph node metastases is discussed as well as the proposal to allocate T2 descriptor within the range 3-5 cm. Finally, series of clinical observations from Japanese experience about small sized T1N0 tumors are presented and discussed.