After adjusting for age, sex, type of regimen, concomitant use of EGFR inhibitors, ICIs and bevacizumab, baseline arterial hypertension, ischemic heart disease, heart failure, chronic kidney disease, cerebrovascular disease, and epilepsy, a complete separation arose when using a multiple variable logistic regression model of the association between early-onset toxicity and early hospital admission. The gene discussed is EGFR; the disease is chronic kidney disease.