Do you prefer monitoring creatinine over cystatin C levels in patients with lymphoma and chronic kidney disease given the potential for cystatin C levels to be increased with certain malignancies?

My default is to monitor creatinine, not cystatin C, in all patients with malignancies except:

• if patients have had weight loss and down-trending creatinine,
• patients are at eGFR cutoffs for chemotherapy drug dosing, leading to concern for potential over/under-dosing,
• there is concern for pseudo-AKI...