{"entity":{"id":"tumour-control-probability-models","kind":"technology","name":"Tumour control and normal tissue complication probability (TCP and NTCP)","aka":[],"tldr":"Curves that turn a radiation dose into a probability: how likely the tumour is to be eradicated and how likely a nearby organ is to be damaged. They underlie dose constraints, dose escalation trials and comparisons between treatment plans.","summary":"Tumour control probability models take the linear-quadratic survival of clonogenic cells and ask how likely it is that none survive a given dose, producing a sigmoid dose-response; normal tissue complication probability models, from Lyman's 1985 formulation to the Lyman-Kutcher-Burman and relative seriality models, do the same for organs, incorporating how much of the organ is irradiated. The QUANTEC reviews of 2010 gathered clinical NTCP data for each organ into the constraints planners use today, and biological plan comparison and dose-painting rest on these curves. Their parameters carry wide uncertainty and immune and vascular effects are absent.","status":"established","asOf":"2026-09-17","links":[{"label":"QUANTEC introduction 2010","url":"https://doi.org/10.1016/j.ijrobp.2009.09.040"},{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Radiobiology"}],"tags":["mathematical-model"],"related":[],"cancers":[],"sections":["ai-computation","drug-discovery"],"technologies":["linear-quadratic-model","imrt-igrt","treatment-planning-systems"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["organs-at-risk","biologically-effective-dose"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"notes":[],"principle":"TCP = exp(-N·S(D)) for N clonogens with survival S(D); NTCP as a sigmoid of the equivalent uniform dose to an organ with volume-effect parameters, fitted to clinical outcome data.","strengths":["Basis of organ dose constraints","Allows biological plan comparison","Fitted to large clinical series (QUANTEC)"],"limitations":["Wide parameter uncertainty","Ignores immune effects and repopulation unless extended","Poorly validated for hypofractionation"],"since":1985},"route":"/technologies/tumour-control-probability-models/","neighbours":{"section":[{"id":"ai-computation","kind":"section","name":"AI & Computation","route":"/fronts/ai-computation/"},{"id":"drug-discovery","kind":"section","name":"Drug Discovery Platforms","route":"/fronts/drug-discovery/"}],"technology":[{"id":"imrt-igrt","kind":"technology","name":"IMRT / IGRT (modern external beam)","route":"/technologies/imrt-igrt/"},{"id":"treatment-planning-systems","kind":"technology","name":"Radiotherapy treatment planning and QA software","route":"/technologies/treatment-planning-systems/"},{"id":"linear-quadratic-model","kind":"technology","name":"The linear-quadratic model and fractionation","route":"/technologies/linear-quadratic-model/"}],"term":[{"id":"biologically-effective-dose","kind":"term","name":"Biologically effective dose (BED) and EQD2","route":"/terms/biologically-effective-dose/"},{"id":"organs-at-risk","kind":"term","name":"Organs at risk and dose constraints","route":"/terms/organs-at-risk/"}]}}