Renal involvement in solid cancers: epidemiological, clinical and histological characteristics study of 154 onconephrology patients.

Background: Onconephrology is a growing discipline that aims to improve the management of patients with cancer and kidney disease. If kidney histology is an essential key, the anatomopathological data remain weak although essential to this complex management.

Methods: Patients with active cancer who had a kidney biopsy (KB) between 2014 and 2020 were included, and their clinicobiological and histological data were analyzed retrospectively.

Results: Our cohort consisted of 154 patients (83 women) with a mean age of 58 years. One hundred twelve patients presented with proteinuria, 95 with acute kidney injury, and 59 with arterial hypertension. Histologically, interstitial fibrosis was found in 74% of KBs, tubular atrophy in 55.1%, arteriolar hyalinosis in 58.4%, and fibrous endarteritis in 54.4%. Regarding the main acute lesions, thrombotic microangiopathy (TMA) was found in 29.9% of biopsies, acute tubular necrosis (ATN) in 51.3%, and acute interstitial nephritis in 24.8%. The etiological diagnosis most often made was the nephrotoxicity of anticancer drugs (87 patients), followed by a pre-renal (15 patients) and kidney disease unrelated to cancer (13 patients). Sixty-seven patients presented with at least 2 associated diagnoses reflecting the complexity of kidney damage in cancer. Different clusters were found, highlighting that immunotherapy and anti-VEGF were the most commonly involved drugs.

Conclusions: During onconephrology practice, kidney toxicity of treatments is the most common etiology. Several mechanisms can be involved, underscoring the importance of kidney biopsy and the complexity of its management. Chronic histological lesions were very common.