Low albumin-corrected plasma zinc is common among patients with bladder cancer undergoing cystectomy

Abstract

Background and aims: Previous studies have shown an association between low zinc levels and different cancer diseases. Furthermore, the risk of zinc deficiency increases with age and malnutrition and is associated with poorer postoperative outcomes. This study evaluated the prevalence and postoperative outcomes of low plasma zinc (p-zinc) and low albumin-corrected p-zinc among patients with bladder cancer undergoing cystectomy.

Methods: A retrospective data collection was conducted in 110 patients with bladder cancer undergoing cystectomy at the Department of Urology at Copenhagen University Hospital, Herlev and Gentofte from July, 2021 to January, 2024. Data included age, Body Mass Index (BMI), standard preoperative blood samples, American Society of Anaesthesiologists classification (ASA score), tumour characteristics, preoperative chemotherapy, postoperative complications, readmissions, and mortality. Albumin-corrected p-zinc levels were calculated to avoid false low p-zinc levels due to hypoalbuminemia. Patients were divided into two groups depending on normal or low albumin-corrected p-zinc levels, with low levels defined as <10 μmol/L.

Results: In total, 43 % of patients had low p-zinc levels, while 30 % had low albumin-corrected p-zinc levels, which is considered being a more acurate measure of zinc level. Patients with low albumin-corrected p-zinc were older and had lower BMI compared with patients with normal levels. More patients, who had received preoperative chemotherapy, had low albumin-corrected p-zinc compared with patients, who had not received preoperative chemotherapy. We saw a tendency towards poorer 1-year survival for patients with low albumin-corrected p-zinc levels (p = 0.069) and lower 30-day readmission (p = 0.054) compared to patients with normal albumin-corrected p-zinc levels.

Conclusion: Low albumin-corrected p-zinc levels were associated with lower BMI, higher age, and preoperative chemotherapy. No significant difference was seen between patients with low and normal albumin-corrected p-zinc levels and survival in this study of patients undergoing surgery for bladder cancer. Future studies are needed to further understand the relationship between p-zinc levels, chemotherapy, and patient outcomes following cystectomy.

Keywords: Albumin-corrected p-zinc; Bladder cancer; Nutritional assessment; Plasma zinc; Readmission; Survival.