Clinical utility of calculated creatinine clearance as a guide to chemotherapy in patients with gynecologic malignancies

Objective: To examine the relationship between calculated and measured creatinine clearance, and also to evaluate the clinical utility of calculated creatinine clearance before administration of chemotherapy in patients with gynecologic malignancies. Methods: In 38 patients with gynecologic malignancies, a total-69 paired creatinine clearance measured by 24-hour urinary creatinine clearance and calculated were compared. Results: The significant correlation (r = 0.597, p < 0.0001) was observed between creatinine clearances determined by both methods. There were 26 (37.7%) 24-hour urine collections. The correlation between two methods improved when these inaccurate samples were excluded (r = 0.876, p < 0.0001). In addition, if a creatinine clearance of 50 ml/min is set as a threshold for dose modification, only 2.9% of the patients would have received reduced doses inappropriately, by using the calculated creatinine clearance alone. Conclusion: These results suggest that in patients with gynecologic malignancies, a calculated creatinine clearance prior to chemotherapy is sufficient for evaluation of renal function and measured creatinine clearance would be determined only when calculated creatinine clearance is below the threshold for dose modification.