Site‐Specific Requirements for pT and pN

This chapter is an expansion to the following general rules of the TNM system (TNM Classification 2010): 2bPathological assessment of the primary tumour (pT) entails a resection of the primary tumour or biopsy adequate to evaluate the highest pT category. The pathological assessment of the regional lymph nodes (pN) entails removal of nodes adequate to validate the absence of regional lymph node metastasis (pN0) and sufficient to evaluate the highest pN category. 4If there is doubt concerning the correct T, N or M category to which a particular case should be allotted, then the lower (i.e., less advanced) category should be chosen. The numbers of lymph nodes given in the different tumour sites are considered adequate for staging. If the examined lymph nodes are negative, but the number ordinarily resected is not met, classify as pN0. The number of nodes examined and the number involved by tumour should be recorded in the pathology report. This information may also be added in parentheses, e.g., for colorectal carcinoma pN0 (0/11) or pN1 (3/10). In many tumour sites, the number of involved regional lymph nodes indicates differences in prognosis. A correlation exists between the number of examined lymph nodes and the pN classification. With increasing number of examined lymph nodes a higher frequency of lymph node-positive cases is found and—in tumour sites where more than one positive pN category is provided—a greater proportion of higher pN categories can be observed. Therefore, the number of examined lymph nodes reflects the reliability of the pN classification. Keywords: Tumors-UT