Figure 4. Hypothetical process of preventive (with a ‘second chance’) and post-diagnostic measures.
A tumour is initiated by one cell and grows to size M0 (either 104 or 106 cells in our numerical studies). Prevention (A) arrests tumour growth at intensity σ (daily level = σ/4). Should the tumour grow to 109 cells, it is diagnosed and resected to M = M0 cells and then treated again at intensity σ. Post-diagnostic intervention (B) does not discover the growing tumour until 109 cells (i.e., ), whereupon it is resected to M = M0 cells and then treated at intensity σ > 0. Either intervention finally ‘fails’ should the tumour attain 109 cells a second time, no later than 50 years after the initial lesion of size M0. Should the tumour be eradicated or not exceed 109 cells by 50 years after the initial lesion, then the intervention is deemed a ‘success’.