Do you adjust chemotherapy dose if >=10% change in calculated dose, weight, BSA, or if any of these three parameters are met?

Our institution has a policy of adjusting chemotherapy doses if there is a 10% change in calculated dose. Since some drugs are based on weight and some on BSA, it gets complicated if we stick with one versus the other. Also, this practice aligns with ASCO recommendations.

We have a similar policy. I reject this concept.

Intrapatient variability in pharmacokinetics is about 30% for all cytotoxics. Dose modification should be according to tolerance. Even with weight loss if the patient is tolerating the dose, just leave it instead of reducing a few milligrams.

For antibodies with longer half-life dose modification may be more justified, yet none of these have clear dose-toxicity relationships in the dosing range we use.