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Klöckl, M.
Estimation versus measurement of the glomerular filtration rate for kidney function assessment in patients with cancer undergoing cisplatin-based therapy
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2018. pp. 60
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- Authors Med Uni Graz:
- Advisor:
- Posch Florian
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- Abstract:
- Introduction: Cisplatin is a widely-used, highly effective antineoplastic drug used in the therapy of a broad spectrum of solid and haematologic malignancies (e.g. cancers of the lung, testicles or esophagus). Due to the risk of cisplatin-induced nephrotoxicity (CIN) it is mandatory to evaluate the kidney function (as represented by the Glomerular Filtration Rate (GFR)) of every patient receiving cisplatin before every cycle. At present, two methods are in use for this purpose: A direct measurement of the GFR using the clearance of creatinine (CCl), and an estimate of the GFR (eGFR) using an approximation formula such as CKD-EPI. Which of these two methods is prefereable is currently unclear. Whereas the CCl require a timed urine collection (usually over 24 hours), the eGFR requires only a simple single blood draw. Although the CCl has at least the potential to be more accurate than the eGFR, errors often occur due to problems on the patient side in complying with the 24-hour urine collection protocol. Therefore, it is not infrequent that the 24-hour collection of urine has to be repeated in an inpatient setting before cisplatin administration, which may lead to longer hospital stays and delayed onset of therapy. Here, the eGFR has the advantage of simplicity. However, it is currently unclear whether eGFR assessment alone is safe for kindey function assessment in patients with cancer undergoing cisplatin therapy. In this study we investigated the concordance between the CCl and the eGFR in this setting, with the ultimate aim of evaluating whether it may be safely possible to omit CCl measurement and only use the eGFR. Materials and Methods: CCl and eGFR measurements from 470 cisplatin chemotherapy cycles from 121 patients who were treated between the 1st of January 2015 and the 4th of April 2016 with cisplatin-based chemotherapy at the Division of Oncology, Medical University of Graz, were analysed in this retrospective study. According to local standard, both CCl and eGFR were routinely measured before every cisplatin cycle and a CCl and/or eGFR measurement <50ml/min/1.73m²represented a contraindication for cisplatin. The primary endpoint was the proportion of cycles where the CCl was < 50 ml/min/1.73m² while the eGFR was = 50 ml/min/1.73m² (i.e. a “false negative” result when only measuring the eGFR). Results: The primary endpoint occurred in eight out of 470 cisplatin cycles (1.7%, 95%CI: 0.5-2.9, p=0.004). In these eight events (from seven individual patients), the CCl was on average 65ml/min/1.73m² (95%CI: 50-80) lower than the eGFR (range:22-101ml/min/1.73m²). The CCl was remeasured in all patients and showed normal results in five patients, an abnormal result due to incompliance with urine collection in one patient and results minimally below 50ml/min/1.73m² in two patients. None of these events precluded the administration of cisplatin at the planned date and no subsequent cases of nephrotoxicity occurred in these seven or any other patients in the study. Among patients with normal kidney function, several CCl and eGFR readings were highly discrepant, with qualitative analysis showing that many patients were incompliant with the 24-hour urine collection. Conclusion: The measurement of the CCl can be safely forgone after the first cycle in patients with cancer undergoing cisplatin therapy.