Concordance between clinical and pathology TNM-staging in lung cancer

•There is a low concordance between the cTNM and pTNM staging in lung cancer.•There is a low concordance between cT and pT descriptors.•Few lymph nodes are examined. A prerequisite for utilizing the tumour, lymph-nodes, and metastases (TNM) for the staging of lung cancer patients is a high quality of the reported data on which the staging is based. The aim of this study was to investigate the concordance between the clinical, cTNM and the pathology, pTNM staging for lung cancer, version 8 as reported to the Cancer Registry of Norway (CRN). A total of 1284 patients who underwent surgery 2018–2019 with sufficient data regarding both clinical and pathology T and N descriptors were included. The differences in tumour diameter reported in the clinical and the pathology notifications were ≤5 mm and ≤10 mm in 65.9 % and in 84.4 % of the cases, respectively. For the c- and pT categories, there was concordance in 53.4 % while 28.4 % were upstaged and 18.2 % were downstaged. For N categories there was concordance in 83.3 % while 13.7 % were upstaged and 3.0 % were downstaged. Unforeseen pN2 was found in 6.2 % of the cases. For TNM staging groups there was concordance in 48.1 % of the cases, while 33.4 % were upstaged and 18.5 % were downstaged. The calculated sensitivity and specificity for reported cTNM staging as diagnostic test for being eligible for adjuvant treatment (stage II–IIIA) were 0.65 and 0.91, respectively. These data on staging for lung cancer, as reported to the CRN, shows a disappointingly low precision and concordance in c- and pTNM staging. This urges a strategy for a marked improvement.