Histopathological Categories of Local Extent of Lung Tumors

Abstract

The pathological features of 405 lung tumors, ascertained on both macroscopic and microscopic examination are reported in detail. On this evidence the tumors were divided into categories by histopathological extent, irrespective of histological type, the aim being to supply a detailed scheme for recording information on the local extent of the disease. In accordance with UICC usage, these categories are denoted by the symbol P. The following 4 P categories are: P1 central or peripheral tumors confined to the lung; P2 tumors involving contiguous structures such as the main bronchus or the visceral pleura, excluding the visceral pleura lining the fissures, which is regarded as included « within » the lung; P3 tumors that have spread to neighbouring structures such as the mediastinal soft tissues and/or viscera (excluding lymph nodes), and chest wall; P4 tumors made up of two or more neoplastic masses within the same lobe or in different lobes of the same lung. The five-year survival rates, calculated by the actuarial method, were: 33.89%, 12.74%, 11.11% and 0.00% for P1, P2, P3 and P4 respectively. The differences between P1 and the rest and between P4 and the rest were statistically significant but not the difference between P2 and P3.