Tumour volume doubling time

Collins and colleagues introduced volume doubling time from serial chest radiographs in 1956. In lung cancer screening it is the main tool for managing indeterminate nodules: the NELSON trial used volume doubling time to classify growth, with faster than 400 days prompting work-up, and it underlies the British Thoracic Society and Lung-RADS pathways. Doubling time also grades kidney masses under surveillance, thyroid nodules and metastases, and, projected backwards, suggests that most cancers have grown for years before detection. Growth is Gompertzian rather than exponential, so a single doubling time is an approximation.