Hi. What's the histology of that base-of-tongue cancer you're asking about? If it's squamous cell carcinoma, some in vitro tongue SCC cell lines have doubling times between 28-40 hours, so it's theoretically possible for a T1 lesion (2 cm diameter or less) to progress to T3 (greater than 4 cm diameter) in less than 45 days. T4 stage would involve not just an increase in size, but invasion of adjacent structures, like bone or extrinsic tongue muscles. The propensity of the tumor to invade depends on its "aggressiveness", which can be estimated by looking at the histology. That's why I asked about it.