Hypophosphatemia is Associated With Postoperative Morbidity After Cytoreductive Surgery and Heated Intraperitoneal Chemotherapy: A Retrospective Study

Introduction: Hypophosphatemia following surgery is associated with a higher rate of postoperative complications; however, the significance of postoperative hypophosphatemia after cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) is unknown. Methods: A prospectively maintained database was queried for all patients who underwent CRS/HIPEC for any histology at the Mount Sinai Health System. The perioperative serum phosphate levels, postoperative complications, and comorbidities were compared between patients with or without major complications. Results: From 2007 to 2018, 327 patients underwent CRS/HIPEC. Most of the patients had low phosphate levels on postoperative day (POD) 2, reaching a median nadir of 2.3 mg/dL on POD 3. Patients with major complications had significantly lower levels of serum phosphate on POD 5-7 compared with patients without complications, with median serum phosphate 2.2 mg/dL (IQR 1.9-2.4) versus 2.7 mg/dL, (IQR 2.3-3), P < 0.01. Hypophosphatemia on POD 5-7 was also more frequent in patients who developed an anastomotic leak, with median serum phosphate 2.2 mg/dL (IQR 1.9-2.6) versus 2.8 mg/dL (IQR 2.2-3.2), P = 0.001. On multivariate analysis, the number of organs resected at surgery, diaphragm resection, postoperative intensive care unit stay, and serum phosphate level <2.4 mg/dL on POD 5-7 were independently associated with a major complication after CRS/HIPEC. Conclusions: Following CRS/HIPEC, POD 5-7 hypophosphatemia is associated with severe postoperative complications and anastomotic leak.