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Assessment of renal function in Japanese children with malignancies using serum cystatin C
Nami Nakamura1,2, Hiroyoshi Watanabe1, Kazumi Okamura1
1Department of Pediatrics, the University of Tokushima Graduate School.
Insights
Serum cystatin C (CysC) levels and CysC-based estimated glomerular filtration rate (CysC-eGFR) can be affected by factors other than kidney function in pediatric cancer patients. These markers may be unpredictable during active disease phases.
Area of Science:
- Pediatric Oncology
- Clinical Chemistry
- Renal Physiology
Background:
- Serum cystatin C (CysC) levels are influenced by various factors beyond renal function.
- Accurate assessment of glomerular filtration rate (GFR) is crucial in pediatric oncology for treatment management.
Purpose of the Study:
- To evaluate the clinical utility of serum CysC and CysC-based estimated GFR (CysC-eGFR) in Japanese children with malignancies.
- To identify factors influencing CysC levels in this patient population.
Main Methods:
- Prospective data collection from 13 pediatric patients (≤17 years) with malignancies over 36 time points.
- Assessment of serum CysC and 24-h creatinine clearance (CCr).
- Analysis of potential confounding factors: tumor activity, chemotherapy response, neutropenia, inflammation, and medications (G-CSF, steroids, levothyroxine).
Main Results:
- No renal dysfunction was indicated by CCr, yet serum CysC levels varied outside reference ranges.
- Elevated serum CysC was more frequent in patients with active disease (no therapy, stable, or progressive) compared to responders (p = 0.0046).
- Correlation between CCr and CysC-eGFR improved significantly when restricted to patients with complete or partial response (r=0.663, p=0.0010) versus all patients (r=0.355, p=0.054).
Conclusions:
- Serum CysC levels can be elevated in pediatric cancer patients irrespective of actual renal function.
- CysC-eGFR may be unreliable during active tumor phases, highlighting the need for careful interpretation in oncology.
- Further research is needed to refine GFR estimation in pediatric cancer patients considering non-renal factors.
Abstract:
Several factors besides renal function influence serum cystatin C (CysC) levels. The present study evaluates the value of serum CysC and the equation for CysC based estimated glomerular filtration rate (CysC-eGFR) for Japanese children with malignancies. We collected information at 36 time points from 13 patients aged ≤ 17 years with malignancies. We assessed tumor activity, cell recovery phase after chemotherapy, neutropenia phase, inflammation response and medication with granulocyte-colony stimulating factor, steroid, and levothyroxine as risk factors associated with serum CysC levels. Although no 24-h creatinine clearance (CCr) data collected at 36 time points indicated renal dysfunction, serum CysC levels were above and below the reference values at four and five time points, respectively. The frequency of elevated serum CysC levels was higher in patients without therapy or with stable or progressive disease than among those with a complete or partial response (p = 0.0046). The correlation coefficient between CCr and CysC-eGFR was 0.355 (p = 0.054), but this improved to 0.663 (p = 0.0010) when restricted to patients with a complete or partial response. Levels of serum CysC might become elevated regardless of renal function, and CysC-eGFR might become unpredictable during the active phase of tumors. J. Med. Invest. 65:231-235, August, 2018.
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