Targeted therapy-induced acute kidney injury (AKI) can complicate oncologic treatment. We present a case of creatinine elevation induced by abemaciclib, a cyclin-dependent kinases 4 and 6 inhibitor used in advanced breast cancer which can also cause nephrotoxicity. A female patient in her mid-sixties was referred to nephrology for elevated serum creatinine after starting abemaciclib. Diagnostic workup, including blood urea nitrogen (BUN), serum cystatin C, urine protein measurement, and serum electrolytes revealed no evidence of renal dysfunction. This case emphasises the importance of distinguishing creatinine elevation from true nephrotoxicity to avoid unnecessary treatment adjustments. Abemaciclib and other targeted therapies can induce creatinine elevation by inhibiting proximal tubule secretory transporters, rather than through direct nephrotoxicity. By incorporating additional assessments such as BUN, serum cystatin C, and additional biomarkers including urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule 1, clinicians can distinguish creatinine elevation from AKI to guide appropriate management of oncologic diseases.
Keywords: Breast cancer; Renal system; Unwanted effects / adverse reactions.
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