Cancer Staging

Cancer staging is an integral part of the initial management of cancer patients that dictates patient care, predicts prognosis and is vital for comparing research outcomes and to improve cancer control. The staging system is based on the anatomic extent of the tumour and a temporal determinism. The TNM oncotaxonomy provides the necessary structural stencil for the T, N and M and the staging systems. The TNM staging is simple, cheap, objective, and accepted worldwide and does not require specialised technology for its application. The TNM has evolved over 50 years, with many revisions to the current 8th edition of cancer staging. It has included 15 organ systems and 130 primary sites. The new staging system has followed the modified Groome’s criteria to avoid heterogeneity while incorporating evidence-based non-anatomic factors. The staging system includes not just the clinical and pathological staging but also the post-therapy, recurrent, and post-autopsy groups. Multiple tumours, residual tumours, unknown primary are detailed, and categorisation of isolated tumour cells, micrometastasis, circulating tumour cells, and disseminated tumour cells and their true significance are additionally described. Various histopathological parameters, prognostic factors, biomarkers, alternate grading systems, and grids are taken into consideration while proposing changes to existing staging classification. The incorporation of molecular signatures into the staging system may evolve a population-based ‘one size fits all’ model into a personalised system based on biological determinism while retaining essential attributes of conventional staging.