CamGFR v2: A New Model for Estimating the Glomerular Filtration Rate from Standardized or Non-standardized Creatinine in Patients with Cancer

Knowledge mapping and visualized analysis of research progress in onconephrology: a bibliometric analysis

OBJECTIVES

Onconephrology is an expanding subspecialty focused on the management of cancer patients with renal injury. This study used a comprehensive bibliometric analysis to emphasize the need for cooperation between oncologists and nephrologists, exploring current trends and future research areas in onconephrology.

METHODS

Relevant literature on onconephrology published between 1 January 2000 and 27 April 2024 was retrieved from the Science Citation Index Expanded of the Web of Science Core Collection, followed by manual screening. Bibliometric analyses were performed using CiteSpace, VOSviewer, and Bibliometrix software.

RESULTS

A total of 1,853 publications, including 1,647 articles and 206 reviews, by 11,606 authors from 2,757 institutions in 73 countries, were analyzed. Annual publications generally follow a steadily increasing trend, ranging from 25 to 161 documents. The United States (n = 464), The University of Texas MD Anderson Cancer Center (n = 39), Meletios A. Dimopoulos (n = 21), and Nephrology Dialysis Transplantation (n = 35) were the most productive country, institution, author, and journal, respectively. Immune checkpoint inhibitors, glomerular filtration rate, and cisplatin were clusters of highly cited references after 2015. Oxaliplatin, calcium, open-label, and thrombotic microangiopathy were trending topics after 2020. Outcome, acute kidney injury, immunotherapy, and chronic kidney disease were keyword bursts that persisted through 2024.

CONCLUSION

Current research of onconephrology is focusing on chemotherapeutic nephrotoxicity, kidney function assessment, dosing of chemotherapeutic agents in chronic kidney disease, glomerular disease in cancer, immunotherapy, and electrolyte disturbances. Future directions in this field include clinical trials and thrombotic microangiopathy.

Donor-acceptor covalent organic framework nanofilm-based laser desorption/ionization mass spectrometry for rapid and sensitive determination of creatinine in human serum

Creatinine (Cre), a metabolite generated by muscles and kidneys, holds significant importance in clinical screening and detection of kidney disease. However, the existing clinical detection of Cre, such as the Jaffe reaction-based colorimetric method, requires complex sample pretreatment and is subject to interference in biological samples. Herein, a surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) method based on a donor-acceptor covalent organic framework (D-A COF) nanofilm as a substrate was proposed for Cre determination in human serum. The D-A COF nanofilm was synthesized using a solvothermal reaction on indium-tin-oxide (ITO)-coated glass plates, which featured uniform surfaces, good thermal stability, and excellent UV absorption. Compared with conventional organic matrices, the D-A COF nanofilm-based LDI-MS method showed low background interference and high MS response and was successfully used for the analysis of low-weight molecules, such as amino acids, bisphenols, and estrogens. On this basis, the D-A COF nanofilm-based LDI-MS method was developed for the determination of Cre in human serum. This method showed good linearity in the range of 14.0-750.0 μmol L-1 with a low limit of detection (LOD) of 4.5 μmol L-1, making it suitable for the determination of Cre in human serum with different concentration levels. This work demonstrates the potential of this method for the clinical determination of Cre in human serum and provides a new direction for the screening and determination of other small-molecule clinical markers.

Assessment of GFR in Patients with Cancer: A Statement from the American Society of Onco-Nephrology

Accurate assessment of GFR is crucial to guiding drug eligibility, dosing of systemic therapy, and minimizing the risks of both undertreatment and toxicity in patients with cancer. Up to 32% of patients with cancer have baseline CKD, and both malignancy and treatment may cause kidney injury and subsequent CKD. To date, there has been lack of guidance to standardize approaches to GFR estimation in the cancer population. In this two-part statement from the American Society of Onco-Nephrology, we present key messages for estimation of GFR in patients with cancer, including the choice of GFR estimating equation, use of race and body surface area adjustment, and anticancer drug dose-adjustment in the setting of CKD. These key messages are based on a systematic review of studies assessing GFR estimating equations using serum creatinine and cystatin C in patients with cancer, against a measured GFR comparator. The preponderance of current data involving validated GFR estimating equations involves the CKD Epidemiology Collaboration (CKD-EPI) equations, with 2508 patients in whom CKD-EPI using serum creatinine and cystatin C was assessed (eight studies) and 15,349 in whom CKD-EPI with serum creatinine was assessed (22 studies). The former may have improved performance metrics and be less susceptible to shortfalls of eGFR using serum creatinine alone. Since included studies were moderate quality or lower, the American Society of Onco-Nephrology Position Committee rated the certainty of evidence as low. Additional studies are needed to assess the accuracy of other validated eGFR equations in patients with cancer. Given the importance of accurate and timely eGFR assessment, we advocate for the use of validated GFR estimating equations incorporating both serum creatinine and cystatin C in patients with cancer. Measurement of GFR via exogenous filtration markers should be considered in patients with cancer for whom eGFR results in borderline eligibility for therapies or clinical trials.

Measurement of Glomerular Filtration Rate in Patients Undergoing Renal Surgery for Cancer: Estimated Glomerular Filtration Rate versus Measured Glomerular Filtration Rate in the Era of Precision Medicine

BACKGROUND

In the era of precision medicine, determining reliable renal function assessment remains a critical and debatable issue, especially in nephrology and oncology.

SUMMARY

This paper delves into the significance of accurately measured glomerular filtration rate (mGFR) in clinical practice, highlighting its essential role in guiding medical decisions and managing kidney health, particularly in the context of renal cancer (RC) patients undergoing nephrotoxic anti-cancer drugs. The limitations and advantages of traditional glomerular filtration rate (GFR) estimation methods, primarily using serum biomarkers like creatinine and cystatin C, are discussed, emphasizing their possible inadequacy in cancer patients. Specifically, newer formulae designed for GFR estimation in cancer patients may not perform at best in RC patients. The paper explores various methods for direct GFR measurement, including the gold standard inulin clearance and alternatives like iohexol plasma clearance.

KEY MESSAGE

Despite the logistical challenges of these methods, their implementation is crucial for accurate renal function assessment. The paper concludes by emphasizing the need for continued research and innovation in GFR measurement methodologies to improve patient outcomes, particularly in populations with complex medical needs.

Glomerular filtration rate measurement during platinum treatment for urothelial carcinoma: optimal methods for clinical practice

BACKGROUND

We assessed the accuracy of four estimated glomerular filtration rate (eGFR) methods: MDRD, Cockcroft-Gault, CKD-EPI, and Wright.

METHOD

The four methods were compared to measure GFR (mGFR) in patients with urothelial urinary tract cancer (T2-T4bNxMx) receiving platinum-based chemotherapy at Rigshospitalet, Copenhagen, from January 2019 to December 2021. Using standardized assays, creatinine values were measured, and mGFR was determined using Technetium-99 m diethylenetriaminepentaacetic acid (Tc-99 m-DTPA) or Cr-51-ethylenediaminetetraacetic acid (Cr-51-EDTA) plasma clearance. Patients (n = 146) with both mGFR and corresponding creatinine values available were included (n = 345 measurements).

RESULTS

The CKD-EPI method consistently demonstrated superior accuracy, with the lowest Total Deviation Index of 21.8% at baseline and 22.9% for all measurements compared to Wright (23.4% /24.1%), MDRD (26.2%/25.5%), and Cockcroft-Gault (25.x%/25.1%). Bland Altman Limits of agreement (LOA) ranged from - 32 ml/min (Cockcroft-Gault) to + 33 ml/min (MDRD), with CKD-EPI showing the narrowest LOA (- 27 ml/min to + 24 ml/min and lowest bias (0.3 ml/min). Establishing an eGFR threshold at 85 ml/min-considering both the lower limit of agreement (LOA) and the minimum cisplatin limit at 60 ml/min-allows for the safe omission of mGFR in 30% of patients in this cohort.

CONCLUSION

CKD-EPI equation emerged as the most suitable for estimating kidney function in this patient group although not meeting benchmark criteria. We recommend its use for initial assessment and ongoing monitoring, and suggest mGFR for patients with a CKD-EPI estimated GFR below 85 ml/min. This approach could reduce costs and decrease laboratory time for 30% of our UC patients.

Cystatin C is glucocorticoid responsive, directs recruitment of Trem2+ macrophages, and predicts failure of cancer immunotherapy

Cystatin C (CyC), a secreted cysteine protease inhibitor, has unclear biological functions. Many patients exhibit elevated plasma CyC levels, particularly during glucocorticoid (GC) treatment. This study links GCs with CyC's systemic regulation by utilizing genome-wide association and structural equation modeling to determine CyC production genetics in the UK Biobank. Both CyC production and a polygenic score (PGS) capturing predisposition to CyC production were associated with increased all-cause and cancer-specific mortality. We found that the GC receptor directly targets CyC, leading to GC-responsive CyC secretion in macrophages and cancer cells. CyC-knockout tumors displayed significantly reduced growth and diminished recruitment of TREM2+ macrophages, which have been connected to cancer immunotherapy failure. Furthermore, the CyC-production PGS predicted checkpoint immunotherapy failure in 685 patients with metastatic cancer from combined clinical trial cohorts. In conclusion, CyC may act as a GC effector pathway via TREM2+ macrophage recruitment and may be a potential target for combination cancer immunotherapy.

Carboplatin dosing in the treatment of ovarian cancer: An NRG oncology group study

OBJECTIVE

To determine the effects of using National Comprehensive Cancer Network (NCCN) guidelines to estimate renal function on carboplatin dosing and explore adverse effects associated with a more accurate estimation of lower creatinine clearance (CrCl).

METHODS

Retrospective data were obtained for 3830 of 4312 patients treated on GOG182 (NCT00011986)-a phase III trial of platinum-based chemotherapy for advanced-stage ovarian cancer. Carboplatin dose per patient on GOG182 was determined using the Jelliffe formula. We recalculated CrCl to determine dosing using Modification of Diet in Renal Disease (MDRD) and Cockcroft-Gault (with/without NCCN recommended modifications) formulas. Associations between baseline CrCl and toxicity were described using the area under the receiver operating characteristic curve (AUC). Sensitivity and positive predictive values described the model's ability to discriminate between subjects with/without the adverse event.

RESULTS

AUC statistics (range, 0.52-0.64) showed log(CrClJelliffe) was not a good predictor of grade ≥3 adverse events (anemia, thrombocytopenia, febrile neutropenia, auditory, renal, metabolic, neurologic). Of 3830 patients, 628 (16%) had CrCl <60 mL/min. Positive predictive values for adverse events ranged from 1.8%-15%. Using the Cockcroft-Gault, Cockcroft-Gault with NCCN modifications, and MDRD (instead of Jelliffe) formulas to estimate renal function resulted in a >10% decrease in carboplatin dosing in 16%, 32%, and 5.2% of patients, respectively, and a >10% increase in carboplatin dosing in 41%, 9.6% and 12% of patients, respectively.

CONCLUSION

The formula used to estimate CrCl affects carboplatin dosing. Estimated CrCl <60 mL/min (by Jelliffe) did not accurately predict adverse events. Efforts continue to better predict renal function. Endorsing National Cancer Institute initiatives to broaden study eligibility, our data do not support a minimum threshold CrCl <60 mL/min as an exclusion criterion from clinical trials.

Estimating kidney function in patients with cancer: A narrative review

AIM

Accurate evaluation of glomerular filtration rate (GFR) is crucial in Oncology as drug eligibility and dosing depend on estimates of GFR. However, there are no clear guidelines on the optimal method of determining kidney function in patients with cancer. We aimed to summarize the evidence on estimation of kidney function in patients with cancer.

METHODS

We searched PubMed for literature discussing the performance of GFR estimating equations in patients with malignancy to create a table of the evidence for creatinine- and cystatin c-based equations. We further reviewed novel estimation techniques such as panel eGFR, real-time measured GFR, and functional magnetic resonance imaging.

RESULTS

The commonly used GFR estimating equations were derived from populations of patients without cancer. These equations may be less applicable in Oncology due to severe sarcopenia, inflammation, and other physiologic changes in patients with cancer. The Cockcroft-Gault equation currently dominates in clinical Oncology despite significant limitations and accumulating evidence for use of the CKD-EPICr formula. Additional considerations in the practice of Oncology include a recently developed equation (CamGFRv2, also called the Janowitz formula) and the use of cystatin c-based equations to overcome some of the barriers to accurate GFR estimation based on creatinine alone.

CONCLUSION

Overall, we suggest using the CKD-EPI equations (either cystatin c or creatinine-based) among patients with cancer in routine clinical practice and measured GFR for patients at a critical threshold for treatment decisions.

Glomerular filtration rate estimation for carboplatin dosing in patients with gynaecological cancers

Background

Carboplatin remains integral for treatment of gynaecological malignancies and dosing is based on glomerular filtration rate (GFR). Measurement via radiotracer decay [nuclear medicine GFR (nmGFR)] is ideal. However, this may be unavailable. Therefore GFR is often estimated using formulae that have not been validated in patients with cancer and/or specifically for gynaecological malignancies, leading to debate over optimal estimation. Suboptimal GFR estimation may affect efficacy or toxicity.

Methods

We surveyed several UK National Health Service Trusts to assess carboplatin dosing practise. We then explored single-centre accuracy, bias and precision of various formulae for GFR estimation, relative to nmGFR, before validating our findings in an external cohort.

Results

Across 18 Trusts, there was considerable heterogeneity in GFR estimation, including the formulae used [Cockcroft–Gault (CG) versus Wright], weight adjustment and area under the curve (AUC; 5 versus 6). We analysed 274 and 192 patients in two centres. Overall, CamGFR v2 (a novel formula for GFR estimation developed at Cambridge University Hospitals NHS Foundation Trust) excelled, showing the highest accuracy and precision. This translated into accuracy of hypothetical carboplatin dosing; nmGFR-derived carboplatin dose fell within 20% of the Cam GFR v2-derived dose in 86.5% and 87% of patients across the cohorts. Among the CG formula and its derivatives, using adjusted body weight in those with body mass index ≥25 kg/m² [CG-adjusted body weight (CG-AdBW)] was optimal. The Wright and unadjusted CG estimators performed most poorly.

Conclusions

When compared with nmGFR assessment, accuracy, bias and precision varied widely between GFR estimators, with the newly developed Cam GFR v2 and CG-AdBW performing best. In general, weight (or body surface area)-adjusted formulae excelled, while the unadjusted CG and Wright formulae or the use of AUC6 (versus nmGFR AUC5) produced risk of significant overdose. Thus, individual centres should validate their GFR estimation methods. In the absence of validation, CG-AdBW or CamGFR v2 is likely to perform well while unadjusted CG/Wright formulae or AUC6 dosing should be avoided.

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Despite therapeutic advances, carboplatin is still used repeatedly for treatment of gynaecological cancers.

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Between centres, there is heterogenous use of GFR estimation methods for carboplatin dosing.

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The novel CamGFR v2 and CG-AdBW are the most accurate estimators.

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The Wright formula, unadjusted CG and the use of AUC6 with estimated GFR should all be avoided.

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If internal validation unavailable, centres should use CamGFR v2 or CG-AdBW for GFR estimation.

A prospective cross-sectional study estimated glomerular filtration rate from creatinine and cystatin C in adults with solid tumors

Current guidelines recommend estimating glomerular filtration rate (eGFR) using creatinine (eGFRcr) with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation as the first test for GFR evaluation, but the Cockcroft-Gault (CG) equation is still commonly used in oncology practice and clinical trials despite increasing evidence of its inaccuracy compared to measured GFR (mGFR). Guidelines recommend eGFR using cystatin C (eGFRcys) or both markers (eGFRcr-cys) as a confirmatory test, but neither was carefully evaluated in cancer patients. Therefore, we compared performance of the CKD-EPI equations and others to the CG equation in adults with a variety of solid tumors. The mGFR was determined by plasma clearance of ⁵¹Cr-EDTA. Bias was defined as the median of the differences between mGFR and eGFR while accuracy was defined as the percentage of estimates that differed by more than 30% from the measured GFR (1-P30). We prospectively recruited 1,200 patients between April 2015 and September 2017 with a mean age and mGFR of 58.8 years and 78.4 ml/min/1.73m², respectively. Bias among eGFRcr equations varied from -8.1 to +6.1 ml/min/1.73 m². CG was the least accurate, 1-P30 (95% confidence interval) was 24.9 (22.4- 27.3)%; CKD-EPI had 1-P30 of 19.1 (16.8-21.2)% while eGFRcr-cys had the best performance: bias -2.0 (-2.6 to -1.1) ml/min/1.73m² and 1-P30 7.8 (6.3-9.4)%. Thus, the CG equation should not be preferred over CKD-EPI equation, and eGFRcr-cys can be used as a confirmatory test in adults with solid tumors. Hence, a major policy implication would be to adopt general practice guideline-recommended methods for GFR evaluation in oncology practice and clinical trials.