The IASLC Lung Cancer Staging Project: Proposals for Revision of the Classification of Residual Tumor after Resection for the Forthcoming (9th) Edition of the TNM Classification of Lung Cancer
The goal of surgical resection is to completely remove a cancer; it is useful to have a system to describe how well this was accomplished. This is captured by the residual tumor (R) classification, which is separate from the TNM classification that describes the anatomic extent of a cancer independent of treatment. The traditional R-classification designates as R0 a complete resection, as R1 a macroscopically complete resection but with microscopic tumor at the surgical margin, and as R2 a resection that leaves gross tumor behind.