Estimation of renal function -- what is appropriate in cancer patients?

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.

Serum Cystatin C as a Potential Marker for Glomerular Filtration Rate in Patients with Cholangiocarcinoma

Background: Cholangiocarcinoma (CCA) is the second most common primary hepatobiliary cancer. These patients have meager prognosis and short-term survival. Precise assessment of glomerular filtration rate is a fundamental aspect of clinical care in cancer patients. Cystatin C has been proposed to be superior to creatinine, a well-known marker of renal function. This study aimed to evaluate cystatin C as a marker of GFR calculation in CCA patients. Materials and Methods: One hundred thirty serum samples from CCA patients and 32 from controls were included in this study. Serum cystatin C was measured using immunoturbidity assay. Estimated glomerular filtration rate was calculated by three equations established by chronic kidney disease epidemiology collaboration (based on creatinine and/or cystatin C). Results: Serum cystatin C in CCA patients was higher than that of controls (p=0.0002). Cystatin C was positively correlated with BUN in CCA group (p=0.019). eGFR based on cystatin C and based on both cystatin C and creatinine in CCA was low with significantly different from those of control (p<0.001). Although there was no difference in eGFR using three equations in control, creatinine based eGFR was high with significantly different from eGFR based on cystatin C and on both creatinine and cystatin C in CCA (P=0.000). Proportion in each eGFR stage by three equations showed a high sensitivity with significantly different in CCA (p<0.05). Conclusion: There was a high sensitivity of cys C with significant difference between creatinine and/or cystatin C based eGFR in CCA patients. It should be taken into consideration of mild changes in eGFR by cystatin C which is important in managing drug dosage for CCA patients.

Comparing glomerular filtration rate equations and the impact of different creatinine assays on the assessment of renal function in cancer patients

BACKGROUND

Equations to estimate glomerular filtration rate based on serum creatinine are commonly used in cancer patients to assess renal function. However, there is uncertainty regarding which equation is most appropriate for this population and the impact of different creatinine assays.

METHODS

Measured isotopic glomerular filtration rate results from 120 oncology patients were used to evaluate and compare all four versions of the Wright equation, Cockcroft and Gault, Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration and the Janowitz and Williams formula; using eight different creatinine assays (five Jaffe, three enzymatic).

RESULTS

The enzymatic version of the Wright equation without creatine kinase performed better than the other versions for all eight creatinine assays. However, MDRD and Janowitz and Williams gave the best overall performance in this patient population. Performance was highly dependent on the creatinine assay used, for example, the percentage of results within 30% of the isotopic glomerular filtration rate (P30) ranged from 90.8% to 60.8% for MDRD.

CONCLUSION

The performance of any equation to estimate glomerular filtration rate is highly dependent on the creatinine assay used. Oncology units should assess the performance of glomerular filtration rate equations using their laboratory creatinine assay to determine whether they can be used safely and effectively in cancer patients.

Assessment of Kidney Function in Patients With Cancer

Cancer patients are living longer. The sequelae of cancer treatment and the role of comorbid conditions present before the diagnosis, such as CKD, have been increasingly recognized. The interface between CKD and cancer is multifaceted. CKD is frequently observed in patients with cancer, and cancer treatment contributes to CKD development and progression. In addition, CKD has been recognized as an important risk factor for cancer development and reduced specific cancer survival. In this context, an accurate evaluation of the glomerular filtration rate (GFR) during oncologic treatment is pivotal and is used to define surgery strategies, program prophylactic management of contrasted examinations, make decisions on cisplatin eligibility, and adjust drug prescriptions, particularly chemotherapy agents. Although the most commonly used equations to estimate GFR based on serum creatinine levels in clinical practice (Cockcroft-Gault, Modification of Diet in Renal Disease Study, and CKD Epidemiology Collaboration equations) have not been validated in patients with cancer in large prospective studies, there is increasingly evidence supporting the use of CKD Epidemiology Collaboration equation to assess the GFR in patients with cancer, including for the use of chemotherapy prescriptions. Many patients with cancer may have changes in nutrition status and clearance measurements such as exogenous filtration markers might be extremely useful when clinical decisions differ depending on the GFR level. Future perspectives include the advent of new serum GFR biomarkers such as cystatin C, beta-trace protein, and beta-2 microglobulin as well as the GFR assessment by measuring total kidney parenchymal volume through image examinations.

Cockcroft-Gault, Modification of Diet in Renal Disease, and Chronic Kidney Disease Epidemiology Collaboration equations for estimating glomerular filtration rates in cancer patients receiving cisplatin-based chemotherapy

Background

Although the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation has been recommended for accurate estimates of glomerular filtration rate (eGFR), there is little information regarding differences in GFR estimates obtained using the Cockcroft-Gault (CG) or Modification of Diet in Renal Disease (MDRD) equations in East Asian cancer patients. We investigated discrepancies in GFR and toxicities in patients treated with cisplatin-based chemotherapy using three equations equations.

Methods

A total of 229 patients were retrospectively recruited. We calculated eGFR using the three equations and separated patients into three categories based on GFR < 10 (group A), 10-50 (group B), and > 50 (group C) mL/min/1.73m². We analyzed chemotherapy toxicities.

Results

The mean eGFR calculated using the CG was the lowest of the values derived using the three equations. Estimates using the MDRD and CKD-EPI equations resulted in reclassifying 32 (71.1%) and 33 (73.3%) of 45 patients, originally placed in group B using the CG into group C. However, only 1 (7.7%) of 13 patients placed in group B using the MDRD were reclassified into group C using the CKD-EPI. Twenty-eight of 45 patients classified into group B using the CG equation were treated with reduced doses of cisplatin. However, these patients did not show significant differences in toxicities compared with other patients taking full doses of cisplatin.

Conclusion

The CG equations underestimated GFR compared to the MDRD and CKD-EPI equations. Therefore, when GFR is estimated using CG equations, East Asian cancer patients may receive insufficient doses of chemotherapeutic agents, including cisplatin.

Correlation of Serum Cystatin C with Glomerular Filtration Rate in Patients Receiving Platinum-Based Chemotherapy

Objectives. Serum cystatin C seems to be an accurate marker of glomerular filtration rate (GFR) compared to serum creatinine. The aim of this work was to explore the possibility of using serum cystatin C instead of serum creatinine to early predict renal failure in cancer patients who received platinum based chemotherapy. Design and Methods. Serum creatinine, serum cystatin C concentrations, and GFR were determined simultaneously in 52 cancer patients received carboplatin-based or cisplatin-based chemotherapy. Serum creatinine was assayed on Cobas C6000-Roche, serum cystatin C assay was performed on AIA 360-Tosoh, and GFR was determined in all patients, before the first cycle of chemotherapy and before the subsequent administrations. Results. In the overall series, for the prediction of a fall of GFR < 80 mL/min/1.73 m², the AUC of the ROC curve for cystatin C was 0,667 and the best threshold was 1.135 mg/L (sensitivity 90.5%, specificity 61.1%). For a GFR fall < 60 mL/min/1.73 m², the AUC of ROC curve for cystatin C was 74.3% and the best threshold was 1.415 mg/L (sensitivity 66.7%, specificity 73.2%). Conclusions. Baseline cystatin C values were not able to predict renal failure during subsequent treatment. In conclusion, serum cystatin C is not a reliable early marker to efficiently predict renal failure in patients receiving chemotherapy.

Magnesium, zinc, arsenic, selenium and platinum urinary excretion from cancer patients of Antofagasta region, Chile: multi-metal approach

Objectives

To evaluate the short-term 24 h urinary excretion of platinum, arsenic, selenium, magnesium and zinc in patients with lung cancer and with cancer other than lungs treated with cisplatin or/and carboplatin from Antofagasta, Chile.

Design

Urine measurements of Pt and Se were made by inductively coupled plasma optical emission spectrometry, As by hydride-generation atomic absorption spectrometry and Mg and Zn by means of flame furnace atomic absorption spectrometry.

Setting

All samples were provided by the Oncological Centre of Antofagasta Regional Hospital (Region of Antofagasta, Chile).

Participants

Ninety 24-h urine samples from cancer patients after the infusion of Pt-base drugs and 10 24-h urine samples from cancer patients not treated with metal-base drugs.

Main outcome measures

Concentrations of Pt, Se, As, Zn and Mg coming from 24-h urine samples.

Results

Pt excreted was not significantly different between patients with lung and other cancers treated with cisplatin. The excretion of Mg, Zn and Se was greater than As. Then, Pt favours the excretion of essential elements. For lung and other types of cancers treated with drugs without Pt, excretion of Mg, Zn and Se was also greater than that of As, suggesting antagonism Mg-Zn-Se–anti-cancer drug relationship.

Conclusions

The amounts of Mg, Zn and Se excreted were greater than for As either with or without Pt-containing drugs, suggesting antagonist Mg-Zn-Se–anti-cancer drug relationships. The excretion of As, Mg, Zn and Se is induced by Pt. Knowledge obtained can contribute to understanding the arsenic cancer mechanism and the As-Mg-Zn-Se-Pt inter-element association for lung cancer and other types of cancer.

Comparative performances of the new chronic kidney disease epidemiology equations incorporating cystatin C for use in cancer patients

AIM

In cancer patients receiving chemotherapy treatment, accurate assessment of kidney function is required. The aim of our study was to investigate whether the inclusion of cystatin C together with creatinine in prediction equations would improve the prediction of glomerular filtration rate (GFR).

METHODS

Plasma creatinine and cystatin C were analyzed in 155 patients (cancer, n = 80, kidney donors, n = 75) undergoing (99m) Technetium diethylenepentaacetic (Tc-DTPA) GFR clearance. Equations by the CKD-EPI (chronic kidney disease epidemiology) group (creatinine-, creatinine + cystatin C-, cystatin C-based, respectively) and Cockcroft-Gault were compared with Tc-DTPA GFR by difference plots, receiver operator characteristics curve analysis, root mean square error, chi-squared analysis and percentage concordance according to carboplatin dosage. Comparisons between two creatinine methodologies (enzymatic vs Jaffe) were also performed.

RESULTS

In the overall group, the combination creatinine and cystatin C equation had 69% of results within 20% of GFR (P20), a sensitivity of 86.3% and a specificity of 73.1% to detect reduced GFR at <90 mL/min/1.73 m(2), and a concordance of 78%. In contrast, the traditional Cockcroft-Gault equation had a P20 of 38.0%, with a large underestimation to predict GFR, thereby accounting for approximately 45% of dosing discordance. No obvious differences were obtained when comparing the performance of equations using the two creatinine methodologies.

CONCLUSION

The inclusion of cystatin C in the CKD-EPI equations improved the prediction of kidney function in the overall population, although probably not sufficiently for it to be favored over radioisotopic GFR for guiding chemotherapy. More research is warranted to further improve estimated GFR equations for these purposes.

Is the eGFR formula adequate for evaluating renal function before chemotherapy in patients with urogenital cancer? A suggestion for clinical application of eGFR formula

BACKGROUND

Accurate evaluation of renal function is required before cancer chemotherapy. Various kinds of formula have been developed for estimating creatinine clearance (Ccr) or glomerular filtration rate (GFR) conveniently. We retrospectively examined the reliability of the GFR estimating formula using the renal function data in cancer chemotherapy.

METHODS

Clinical data of 12 patients with urogenital cancer from 1998 to 2013 in Saga University Hospital were reviewed. Patients were treated with 6-21 (median 10.5) courses of chemotherapy and those patients underwent 9-29 (median 14.5) times of 24hrCcr tests before and during chemotherapy. We compared estimated GFR (eGFR) with 24hrCcr. In addition, we developed a novel method to estimate the Ccr using the patient-inherent 24hrCcr/eGFR ratio, which is calculated from initial 3 or 4 determinations of 24hrCcr and the corresponding eGFR. Those estimated Ccrs were also compared with 24hrCcr.

RESULTS

The dissociation between 24hrCcr and eGFR was not constant, and a large dissociation was observed in some cases. The newly devised estimated Ccr demonstrated less dissociation from 24hrCcr compared with eGFR.

CONCLUSIONS

The eGFR formula is not adequate for the clinical use in cancer chemotherapy. The absolute value of eGFR is not reliable, but clinical use of eGFR as relative value seems to be acceptable. To avoid troublesome 24hrCcr measurement in long-term cancer chemotherapy, eGFR formula can be used for estimating Ccr in combination with the specific inherent 24hrCcr/eGFR ratio, which is obtained from 3 or 4 times of actual 24hrCcr measurements.

The validity of the modification of diet in renal disease formula in HIV-infected patients: a systematic review

RATIONALE, AIMS AND OBJECTIVES

Renal dysfunction is highly prevalent in HIV-infected patients and may require dose adjustment of renally excreted antiretroviral drugs. The Modification of Diet in Renal Disease (MDRD)-4 formula is frequently used in daily practice to estimate patients' renal function. The aim of this systematic review was to assess the validity of the MDRD-4 formula in HIV-infected patients.

METHOD

A systematic search in Pubmed and EMBASE was done to identify studies which compared MDRD-4 with measured glomerular filtration rate (mGFR) in HIV-infected patients.

RESULTS

Five studies were included, which provided data from 464 HIV-infected patients with mean mGFR ranging from 87 to 118 ml/min/1.73 m(2). In all studies, results from the MDRD-4 gave an underestimation of the mGFR. Mean bias ((MDRD-4) - mGFR) ranged from -6 to -11 ml/min/1.73 m(2) across studies. The accuracy expressed in terms of P 30 ranged from 64 to 89 %.

CONCLUSIONS

The MDRD-4 formula is as valid in HIV-positive as in HIV-negative patients. Because the available studies comprised mainly HIV-infected patients with mildly impaired to good renal function (GFR ≥ 60 ml/min/1.73 m(2)), more research is needed to validate the MDRD-4 formula in HIV-infected patients with moderate to severe renal impairment.

Nephrotoxicity of recent anti-cancer agents

Cancer patients may develop a variety of kidney lesions that impair not only their immediate survival but also limit the adequate treatment of the underlying malignant process. This review summarizes the nephrotoxic potential of some of the most recently developed anti-cancer drugs, focusing on those interfering with the vascular endothelial growth factor and epidermal growth factor receptor pathways and mammalian target of rapamycin inhibitors. Thrombotic microangiopathy (haemolytic-uraemic syndrome), proteinuria, hypertension and magnesium depletion are the most common side effects. Also the risk for developing acute kidney injury in patients with advanced prostate cancer undergoing androgen deprivation therapy is discussed.

Impact of chronic kidney disease on the risk of clinical outcomes in patients with cancer-associated venous thromboembolism during anticoagulant treatment

BACKGROUND

Information on recurrent venous thromboembolic events (VTEs) and major bleeding risks during anticoagulant treatment in patients with cancer-associated VTEs and chronic kidney disease (CKD) is scarce, although it is of relevance in establishing better tailored management strategies in these patients.

OBJECTIVES

We compared risks of recurrent VTEs and major bleeds in cancer-associated VTE patients with and without CKD.

METHODS

A total of 1684 patients diagnosed with a cancer-associated VTE between 2001 and 2011 were followed for 180 days after VTE diagnosis. Patients were treated mainly with low-molecular-weight heparin (LMWH) or vitamin-K antagonists (VKA). Primary outcomes were recurrent VTE and major bleeding. Secondary outcome was fatal bleeding.

RESULTS

Recurrent VTEs occurred in 15.9/100 patient years (py) in patients without CKD (eGFR > 60 mL min(-1) ), 19.5/100 py in those with CKD stage 3A (eGFR 45-60 mL min(-1) ), 14.9/100 py in those with CKD 3B (eGFR 30-45 mL min(-1) ), and 6.8/100 py in patients with CKD 4-5 (eGFR < 30 mL min(-1) ). Major bleeding occurred in 11.4/100 py in patients without CKD, 18.5/100 py in those with CKD stage 3A, 16.0/100 py in those with CKD 3B, and 40.8/100 py in patients with CKD 4-5. Fatal bleeding occurred in 1.1/100 py, 3.4/100 py, 6.3/100 py and 15.7/100 py, respectively. These increased bleeding risks in CKD patients were mainly observed in those on LMWH treatment, not VKA.

CONCLUSIONS

The risk of major bleeding was increased in CKD patients with VTE and cancer, and was most prominent in those treated with LMWH and an eGFR < 30 mL min(-1) . These results indicate that LMWH should be used with caution in this specific population.

Dosing of cytotoxic chemotherapy: impact of renal function estimates on dose

BACKGROUND

Oncology clinicians are now routinely provided with an estimated glomerular filtration rate on pathology reports whenever serum creatinine is requested. The utility of using this for the dose determination of renally excreted drugs compared with other existing methods is needed to inform practice.

PATIENTS AND METHODS

Renal function was determined by [Tc(99m)]DTPA clearance in adult patients presenting for chemotherapy. Renal function was calculated using the 4-variable Modification of Diet in Renal Disease (4v-MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Cockcroft and Gault (CG), Wright and Martin formulae. Doses for renal excreted cytotoxic drugs, including carboplatin, were calculated.

RESULTS

The concordance of the renal function estimates according to the CKD classification with measured Tc(99m)DPTA clearance in 455 adults (median age 64.0 years: range 17-87 years) for the 4v-MDRD, CKD-EPI, CG, Martin and Wright formulae was 47.7%, 56.3%, 46.2%, 56.5% and 60.2%, respectively. Concordance for chemotherapy dose for these formulae was 89.0%, 89.5%, 85.1%, 89.9% and 89.9%, respectively. Concordance for carboplatin dose specifically was 66.4%, 71.4%, 64.0%, 73.8% and 73.2%.

CONCLUSION

All bedside formulae provide similar levels of concordance in dosage selection for the renal excreted chemotherapy drugs when compared with the use of a direct measure of renal function.

Urinary excretion of platinum, arsenic and selenium of cancer patients from the Antofagasta region in Chile treated with platinum-based drugs

BACKGROUND

Arsenic exposure increases the risk of non-cancerous and cancerous diseases. In the Antofagasta region in Chile, an established relationship exists between arsenic exposure and the risk of cancer of the bladder, lung and skin. Platinum-based drugs are first-line treatments, and many works recognise selenium as a cancer-fighting nutrient. We characterised the short-term urinary excretion amounts of arsenic, selenium and platinum in 24-h urine samples from patients with lung cancer and those with cancer other than lung treated with cisplatin or/and carboplatin. As - Se - Pt inter-element relationships were also investigated.

RESULTS

The amounts of platinum excreted in urine were not significantly different between patients with lung cancer and those with other cancers treated with cisplatin, despite the significant variation in platinum amounts supplied from platinum-based drugs. In general, the analytical amounts of excreted selenium were greater than those for arsenic, which could imply that platinum favours the excretion of selenium. For other types of cancers treated with drugs without platinum, excretion of selenium was also greater than that of arsenic, suggesting an antagonist selenium-anti-cancer drug relationship.

CONCLUSIONS

Regards the baseline status of patients, the analytical amounts of excreted Se is greater than those for As, particularly, for cisplatin chemotherapy. This finding could imply that for over the As displacement Pt favours the excretion of Se. The analytical amounts of excreted Se were greater than those for As, either with and without Pt-containing drugs, suggesting an antagonist Se-anti-cancer drug relationship. However, it seemed that differences existed between As - Se - Pt inter-element associations in patients treated for lung cancer in comparison with those treated for cancer other than lung. Therefore, knowledge obtained in this work, can contribute to understanding the arsenic cancer mechanism and the As - Se - Pt inter-element association for lung cancer and other types of cancer, which in some cases respond at a linear mathematical model.

Estimation of renal function in lung cancer patients

INTRODUCTION

In lung cancer patients treated with chemotherapy, renal function is an important parameter to be monitored. Since measurement of renal function with either isotope or creatinine clearance is time consuming and expensive, we evaluated which of the following equations: Cockcroft-Gault (CG), Wright, modification of diet in renal disease equation (MDRD), MDRD adjusted for body surface area (BSA) and chronic kidney disease epidemiology collaboration (CKD-EPI) best resembles endogenous creatinine clearance (ECC) and could therefore replace its measurement in clinical practice.

METHODS

218 lung cancer patients, who had their 24-h creatinine secretion in urine measured prior to the start of any chemotherapy, were included. Estimation of renal function was calculated and compared to ECC.

RESULTS

There were no major differences in the performance of the tested equations. Mean percentage error of more than 20% and general underestimation was common to all equations. Wright equation performed best although it describes only 43% of ECC variability. Mean measured ECC was 94 mL/min (95% confidence interval [CI]: 90-98 mL/min) and 90 mL/min for Wright equation (95% CI: 87-93 mL/min) (Supp. Fig. 3). MDRD and CKD-EPI equation performed poorest since they do not include any body size descriptor. Large deviations of differences were observed, with a median standard deviation of more than 20% and deviations from ECC exceeding 100%. Wright equation performed best, whereas, despite their leading role in the detection of renal diseases, the MDRD and CKD-EPI equation performed poorest since they do not include any body size descriptor. In the range of ECC<50 mL/(min×1.73 m(2)), the CG equation most often detected a contraindication for cisplatin use. Differences between ECC and calculated values correlated with patients' weight, BSA and body mass index when these were not included in the equation itself.

CONCLUSIONS

In evaluating the renal function of lung cancer patients, equations adjusted for body size descriptors should be preferred. Estimated renal function should be interpreted against the characteristics of patient's body size and special attention is needed when these are reaching the extremes.

Evaluation of glomerular filtration rate estimation by Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae in oncology patients

BACKGROUND

The aim was to evaluate the accuracy of Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae as a substitute for the gold standard measure of glomerular filtration rate (GFR) using chromium 51 EDTA.

PATIENTS AND METHODS

Retrospective analysis of GFR measurements in oncology patients from a University Teaching Hospital over 3 years was carried out. Bias and precision of estimates of GFR were compared with measured GFR.

RESULTS

Six hundred and sixty patients with measured GFR (median 90 ml/min, range 23-179 ml/min) were identified. Cockcroft-Gault produced the smallest bias (median percentage error -1.4%) and highest precision (median absolute percentage error 14.0%) and was the most accurate for carboplatin dosing. For patients>30% over their ideal body weight (IBW), using IBW+30% in the Cockcroft-Gault formula was more precise than using actual body weight or IBW. The Wright formula was most accurate for patients aged 70+years and patients with a body mass index (BMI)≥30 but overestimated GFR when GFR<50 ml/min.

CONCLUSIONS

When measured GFR is unavailable, we advise estimating GFR using the Cockcroft-Gault formula and using IBW+30% for patients weighing>30% over their IBW. If the GFR is ≥50 ml/min and the patient is >70 years and/or BMI≥30, the Wright formula gives the best estimate of GFR.

Accuracy of GFR estimation by the Cockroft and Gault, MDRD, and Wright equations in Oncology patients with renal impairment

Estimation of renal function is crucial to guidance of systemic chemotherapy. With stable creatinine levels, the glomerular filtration rate (GFR) is often estimated from a single measurement of serum creatinine. We compared accuracy of the Cockroft and Gault (C&G), modifying diet in renal diseases (MDRD) and Wright estimates in Oncology patients with renal impairment. Analysis was carried out on the basis of monodentate platinum treatment as the nephrotoxic mechanism of these drugs may affect accuracy of these estimates. Sixty-two consecutive patients with stable creatinine levels who had isotopic GFR measurement of ≤ 60 ml min(-1) at a regional cancer center were reviewed. Twenty-nine were on monodentate platinum treatment. Isotopic GFR was compared with estimated GFR by the three equations. We defined three categories of estimate based on the fractional difference from isotopic GFR: 'perfect' (< 10%), 'reasonable' (≥ 10% but < 30%) and 'poor' (≥ 30%). There was a trend toward provision of more perfect estimates by the MDRD equation particularly in patients on monodentate platinum treatment. Similar numbers had poor estimates from either of these equations, particularly at extremes of body weight. The MDRD formula may be the most accurate of these equations in Oncology patients with renal impairment, particularly with monodentate platinum treatment.

Cancer and renal insufficiency results of the BIRMA study

Background:

Half of anticancer drugs are predominantly excreted in urine. Dosage adjustment in renal insufficiency (RI) is, therefore, a crucial issue. Moreover, patients with abnormal renal function are at high risk for drug-induced nephrotoxicity. The Belgian Renal Insufficiency and Anticancer Medications (BIRMA) study investigated the prevalence of RI in cancer patients, and the profile/dosing of anticancer drugs prescribed.

Methods:

Primary end point: to estimate the prevalence of abnormal glomerular filtration rate (GFR; estimated with the abbreviated Modification of Diet in Renal Disease formula) and RI in cancer patient. Secondary end point: to describe the profile of anticancer drugs prescribed (dose reduction/nephrotoxicity). Data were collected for patients presenting at one of the seven Belgian BIRMA centres in March 2006.

Results:

A total of 1218 patients were included. The prevalence of elevated SCR (⩾1.2 mg per 100 ml) was 14.9%, but 64.0% had a GFR<90 ml min⁻¹ per 1.73 m². In all, 78.6% of treated patients (n=1087) were receiving at least one drug needing dosage adjustment and 78.1% received at least one nephrotoxic drug. In all, 56.5% of RI patients receiving chemotherapy requiring dose reduction in case of RI did not receive dose adjustment.

Conclusions:

The RI is highly frequent in cancer patients. In all, 80% of the patients receive potentially nephrotoxic drugs and/or for which dosage must be adjusted in RI. Oncologists should check the appropriate dose of chemotherapeutic drugs in relation to renal function before prescribing.