Renal Lesions with Low-level Enhancement on Contrast-enhanced CT Promotes Early Detection of Drug-induced Kidney Injury in Patients Administered Anti-cancer Drugs

Background: Some patients with cancer-administered anti-cancer drugs may develop renal lesions with low-level enhancement on follow-up abdominal computed tomography (CT).Objective: To explore the clinical significance of renal lesions with low-level enhancement on CT after exposure to anti-cancer drugs.Methods: Medical records of patients with cancer who developed renal lesions on CT after exposure to anti-cancer drugs were retrospectively reviewed. Renal lesions were scored according to the extent of involvement, CT attenuation values of lesions and normal parenchyma were measured on pre-contrast CT and three phases of contrast-enhanced CT, and changes in serum creatinine (SCr) from one week before exposure to drugs to one week before and after the appearance of renal lesions were recorded.Results: This study included 54 patients (86 lesions). Lesions were slightly lower density on pre-contrast CT, and less enhancing than normal renal parenchyma, especially in the delayed phase. Lesions were wedge-shaped, and involved the renal pyramid and associated renal cortex, as well as, were single or multiple, and occurred in the unilateral or bilateral kidneys. There were patchy and cord-like shadows of increased density in adjacent perirenal adipose tissue. During follow-up, lesions disappeared in 15 patients and persisted in 39 patients without significant progression. There were significant differences in renal lesions and normal renal parenchyma CT attenuation values in each phase of contrast-enhanced CT. Change in SCr level was significantly positively correlated with lesion score.Conclusion: Renal lesions with low-level enhancement on CT suggest early drug-induced kidney injury. These findings will inform clinical decision-making.