#2557 Clinical and histological findings in cancer patients—a single center study

Abstract Background and Aims During the last years, there has been an outstanding improvement in cancer treatment. As patients’ survival has been elongated, the prevalence of kidney injury is increasing. However, clinicopathological data are limited in these patients. We aimed to assess the spectrum of kidney biopsy findings in cancer patients and their relation to treatment. Method Single center retrospective study of all patients with solid and hematologic malignancies, who underwent kidney biopsy due to renal impairment, from September 2015 to July 2023. Clinical, laboratory, histopathological and therapeutic data were evaluated Results Fifty-four patients were biopsied, 35 men and 21 women, of median age 66 (42-84) years and follow up 15 (3-84) months. Median serum creatinine was 3 (0.5-22) mg/dl and proteinuria 3 (0.1-23) gr per day at the time of biopsy. Among the solid malignancies (38/54), lung cancer was the commonest (11), followed by gastrointestinal (5), breast (4), sarcoma (5) and melanoma (3); the rest 10 included other solid malignant tumors. Hematologic malignancies (16/54) were mainly multiple myeloma (6) and lymphomas (5), followed by lymphoblastic leukemia (3) and AL amyloidosis (2). The most frequent indication of biopsy was acute kidney injury (AKI) (29/54), followed by both AKI and proteinuria (15/54) and proteinuria with preserved kidney function (9/54); out of 24 patients with proteinuria, 12 exhibited nephrotic range proteinuria (median 10, 3.5-23 gr/day). At the time of biopsy, more than half of patients (30/54) were on cancer treatment; 5 on immunotherapy, 11 on immunotherapy combined to chemotherapy, 10 on chemotherapy solely and four of them received other kind of treatment. Glomerulonephritis (GN) was shown on 24/54 patients. Among GN, focal segmental glomerulosclerosis (FSGS) was the most common lesion (7), followed by light chain deposit disease (LCDD, 3) and membranous nephropathy (MN, 2); among the last, a rare case of MN with a full-house immunoflorescence pattern was reported. Notably, four patients showed amyloidosis (three AL-amyloidosis linked to multiple myeloma and one AA-amyloidosis possibly related to immunotherapy). A rare case of bevacizumab-induced hyaline occlusive glomerular microangiopathy is also reported. The rest 7/24 cases included glomerulosclerosis (1), minimal change disease (MCD, 1), IgA nephropathy (1), diabetic nephropathy (2) and membranoproliferative glomerulonephritis (2). Tubulointerstitial lesions were found on 30 patients. Acute interstitial nephritis (AIN), acute tubular necrosis (ATN) and combination of two (AIN+ATN) were found on 7, 4 and 12 patients respectively (23 in total). Of note, four out of five patients receiving ifosfamide for sarcomas, presented karyomegalic tubulointerstitial nephritis. Four patients, (three with B-cell lymphoma and one with urothelial carcinoma) exhibited renal infiltration by tumor cells. In addition, two patients were shown with oxalate nephropathy and one with nephrocalcinosis. Kidney disease was secondary to treatment in 23 patients, predominantly attributed to immunotherapy (13). Based on histological findings, cancer treatment was withheld in all patients (23/23).Sixteen of all patients received specific treatment for kidney injury, including corticosteroids, cyclosporine or colchicine. In most of them (14), kidney injury was evaluated as secondary to treatment; Two patients, who presented FSGS and MCD, exhibited renal damage attributed to cancer itself. All treated patients (16/16) recovered renal injury. A small proportion of patients (6/54) underwent dialysis—two due to oxalate nephropathy, two with ifosfamide toxicity, one with LCDD and the last due to sepsis. Half of patients (27/54), including 5/6 who were on dialysis, died during observation period. Conclusion Diagnosing and managing kidney injury in cancer patients may be a challenging task. In our single center study, kidney biopsy revealed diverse and rare histological findings, which necessitated tailored therapeutic interventions.