I find it interesting that many patients (including myself) are told there is no relationship between chemo side effects and response - i.e. having more side effects does not predict a better response. This is even published by the peak cancer body in my country.
However after some reading, it does seem that there is a pretty decent correlation - particularly between the number of side effects experienced (more is better) and the timing (earlier is better). Neutropenia seems to be the most correlated, especially if experienced early (within first few cycles). Severity of side effects doesn’t seem to be predictive however, so the best scenario seems to be to get many side effects, early, mildly.
I realise this is not a guarantee of a response, but I’m surprised this isn’t discussed more. Perhaps they don’t want to worry the (lucky) patients that don’t have major side effects, and have them seek higher, potentially toxic doses?
I asked my onc and he confirmed that indeed he doesn’t like to see his chemo patients looking “too well” (lol), especially given the uncertainties around optimum dosing.
Anyway, knowing this really helped me when I did experience side effects - knowing my chances of a response were better.