Acute Kidney Injury in Patients Receiving Systemic Treatment for Cancer: A Population-Based Cohort Study

A methodology for determining dosing recommendations for anticancer drugs in patients with reduced kidney function

Reduced kidney function (or kidney dysfunction) is commonly an exclusion criterion for randomised controlled trials (RCTs) in cancer. Consequently, high quality evidence for anticancer drug dosing in reduced kidney function is limited and no internationally agreed guidelines exist to inform prescribing decisions in this population. A methodology for guideline development was applied which did not require availability of RCTs but used critical appraisal of existing observational literature and group consensus. An international multidisciplinary working group (n = 38) established consensus recommendations in two parts to form the International Consensus Guideline on Anticancer Drug Dosing in Kidney Dysfunction (ADDIKD). The approach enabled virtual participation worldwide. In Part 1 we developed a standardised approach for assessment and classification of kidney function in patients with cancer using global nephrology standards and working group expertise. Part 2 involved a comprehensive literature search of 59 anticancer drugs followed by a critical appraisal of the evidence certainty through the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process and development of dosing recommendations in reduced kidney function. Key external stakeholders (n = 9) invited expert contributors (n = 25), and the working group participated in virtual interactive workshops to vote on the acceptability of these recommendations. The participants were provided with evaluation of the literature, and they engaged in several rounds of virtual discussion (involving robustness of the evidence behind recommendations and their real-world application) and anonymous consensus voting. Adapting the ADDIKD guideline development process to a virtual format enabled engagement with a very broad base of specialised international experts especially during the global pandemic. Combining GRADE methodology with consensus-building approaches was an effective method of producing recommendations (in an area lacking RCTs) by merging critical review of the literature with expert opinion and clinical practice.

Funding

Development of the ADDIKD guideline is funded by the Cancer Institute NSW as part of the NSW Government and received no funding from external commercial sources.

Aligning kidney function assessment in patients with cancer to global practices in internal medicine

The kidney disease: Improving Global Outcomes (KDIGO) guideline recommends assessing kidney function using glomerular filtration rate (GFR) either through direct measurement or through estimation (eGFR) and describes a standardised classification of reduced kidney function. KDIGO guidelines have been adopted by most internal medicine specialities for the assessment and classification of kidney function, but not by cancer medicine. The development of the International Consensus Guideline on Anticancer Drug Dosing in Kidney Dysfunction (ADDIKD) aims to overcome the perceived challenges with KDIGO recommendations by describing their utility in patients with cancer. Two virtual, consensus building workshops were held consecutively, involving international, multidisciplinary participants (Part 1 of ADDIKD development). During these workshops, three consensus recommendations were agreed upon based on KDIGO's principles; to standardise kidney function assessment, classify kidney function, and determine a uniform approach to dose anticancer drugs in patients with reduced kidney function. Cancer clinicians attending the workshops identified issues regarding the adoption of KDIGO's recommendations. These issues were addressed by nephrologists, clinical pharmacologists, and other clinicians with extensive experience in the contemporary assessment of kidney function. The key concern for cancer specialists was a hesitancy to move away from the familiar and long-standing practice of using the Cockcroft-Gault equation to estimate creatinine clearance. The consensus building within the two multidisciplinary workshops allowed a thorough assessment of the evidence and clarified how directly measured GFR and eGFR, rather than creatinine clearance, could be optimally utilised in cancer care. The development of Part 1 of the ADDIKD guideline represents a standardised, contemporary approach to the assessment, classification, and utility of kidney function in the setting of cancer care and it harmonises with the approach used in other areas of medicine internationally.

Funding

Development of the ADDIKD guideline is funded by the Cancer Institute NSW as part of the NSW Government and received no funding from external commercial sources.

Validation of a cancer population derived AKI machine learning algorithm in a general critical care scenario

PURPOSE

Acute Kidney Injury (AKI) is the sudden onset of kidney damage. This damage usually comes without warning and can lead to increased mortality and inpatient costs and is of particular significance to patients undergoing cancer treatment. In previous work, we developed a machine learning algorithm to predict AKI up to 30 days prior to the event, trained on cancer patient data. Here, we validate this model on non-cancer data.

METHODS/PATIENTS

Medical Information Mart for Intensive Care (MIMIC) is a large, freely available database containing de-identified data from patients who were admitted to the critical care units of the Beth Israel Deaconess Medical Center. Data from 28,498 MIMIC patients were used to validate our algorithm, non-availability of Total Protein measure being the largest removal criterion.

RESULTS AND CONCLUSIONS

Applying our algorithm to MIMIC data generated an AUROC of 0.821 (95% CI 0.820-0.821) per blood test. Our cancer derived algorithm compares positively with other AKI models derived and/or tested on MIMIC, with our model predicting AKI at the longest time frame of up to 30 days. This suggests that our model can achieve a good performance on patient cohorts very different to those from which it was derived, demonstrating the transferability and applicability for implementation in a clinical setting.

Kidney disease in multiple myeloma

Renal disease is a frequent complication of symptomatic multiple myeloma, that increases morbidity and reduces quality of life and overall survival. It may result from various lesions, the most frequent being light chain cast nephropathy (LCCN), related to precipitation of monoclonal free light chains (FLC) with uromodulin in distal tubules. Rapid identification of the type of kidney disease with appropriate management is key. LCCN typically reveals the underlying myeloma and manifests with severe acute kidney injury, high serum FLC level (>500 mg/l) and predominant light chain proteinuria (urine albumin/creatinine ratio <10 %). Urgent therapy is required, based on vigorous fluid expansion, correction of precipitating factors and introduction of efficient anti-myeloma therapy which choice should consider renal elimination of each agent and patient frailty. Early and deep reduction in serum FLC level conditions renal recovery, warranting assessment of efficacy by serial serum FLC level monitoring. In newly diagnosed patients, the combination of bortezomib, high-dose dexamethasone and an anti-CD38 monoclonal antibody is commonly used. The benefit to risk balance of quadruplets incorporating cyclophosphamide or an immunodulatory agent requires to be evaluated in prospective studies. In patients with severe acute kidney injury, reinforcing chemotherapy with FLC removal through plasma exchange or high-cutoff hemodialysis may increase the probability of renal response, despite controversial data from randomized trials. Histological assessment of the extent of cast formation and interstitial fibrosis/tubular atrophy may help evaluating renal prognosis and refining therapy. Thanks to improved overall survival, renal transplantation may be considered in selected candidates with end-stage kidney disease.

Risk of and Mortality After Acute Kidney Injury Following Cancer Treatment: A Cohort Study

BACKGROUND

Acute kidney injury (AKI) can be a severe complication in cancer patients. However, uncertainty remains regarding the risk of and prognosis after AKI following cancer treatments. We therefore aimed to examine the risk of and mortality after AKI following a wide range of specific cancer treatments, including surgical procedures, anticancer drugs, and hematopoietic stem cell transplantations (HSCTs).

METHODS

We conducted a nationwide population-based cohort study. We included adult patients receiving cancer treatment in Denmark from 2010 to 2024. We calculated the risk of AKI within 7 days after surgeries, 1 year after initiation of anticancer drugs, and 100 days after HSCTs. Furthermore, we examined the 1-year mortality in patients with and without AKI following cancer treatment.

RESULTS

We identified 357,870 cancer patients. The 7-day risk of AKI after surgery ranged from 0.3% (breast cancer surgery) to 68.9% (radical nephrectomy in kidney cancer) while the 1-year risk following anticancer drug treatment ranged from 3.5% (cyclophosphamide in breast cancer) to 79.3% (all drugs in acute lymphatic leukemia). The 100-day AKI risk following HSCT ranged from 20.7% (multiple myeloma) to 81.8% (leukemia). For most treatments, AKI was associated with a higher 1-year hazard ratio and risk of death, with exceptions including radical nephrectomy in kidney cancer.

CONCLUSION

In conclusion, several cancer treatments were associated with a high risk of AKI, and AKI was associated with increased mortality in most treatments. These findings highlight the prognostic value of assessing kidney function following specific cancer treatments in clinical practice.

Novel Biomarkers and Imaging Tests for Acute Kidney Injury Diagnosis in Patients with Cancer

The lack of noninvasive urine and blood-based biomarkers for the diagnosis of AKI in patients with cancer is an area of significant unmet clinical need. Traditional noninvasive diagnostic tools that are currently used in the clinic, such as creatinine and cystatin C-based eGFR measurements, urinalysis, urine sediment examination, urine protein quantification, and urine electrolyte measurement, lack the sensitivity and specificity to distinguish between the various underlying etiologies of AKI in patients with cancer. Imaging-based diagnostics can be helpful to rule out urinary obstruction, but also lack sensitivity and specificity to diagnose the etiology of AKI. Kidney biopsy is often required for definitive diagnosis. As our scientific understanding of the biological pathways that are dysregulated in AKI has advanced, there has been considerable interest in developing new biomarkers for AKI. For example, the diagnosis of acute interstitial nephritis, which can occur in patients treated with immune checkpoint inhibitors, promises to be revolutionized by the incorporation of urinary testing for inflammatory biomarkers, such as C-X-C motif ligand 9, TNF- α , and IL-9. In the case of cisplatin administration, biomarkers such as neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 may improve prognostication, differentiating between persistent AKI resulting from acute tubular injury versus prerenal azotemia. The development and validation of blood, urine, and imaging biomarkers into widely used diagnostic tests will require a concerted effort, but could improve diagnosis, management, and prognostication for a growing group of patients who are at high risk of developing AKI during the course of their illness.

Prevalence of kidney disease in patients with different types of cancer or hematological malignancies: a cross-sectional study

PURPOSE

This study investigated the prevalence and risk factors of acute kidney injury (AKI) and chronic kidney disease (CKD) in cancer patients with the aim of providing guidance for clinical treatment of cancer patients.

METHODS

A retrospective study was conducted on all cancer and hematological malignancy patients admitted to Xuanwu Hospital, Capital Medical University, from January 2018 to July 2023. The study population included patients aged 18-80 years with a confirmed cancer or malignancy diagnosis. Chi-square tests, Spearman's correlation, and logistic regression were used to evaluate the relationships between demographic factors, comorbidities, cancer types, antitumor drugs and the prevalence of AKI/CKD.

RESULTS

Among the 2438 participants, the prevalence rates of AKI and CKD were 3.69% and 7.88%, respectively. Patients with diabetes had higher prevalence of AKI/CKD than those without diabetes (OR = 1.66, 95% CI 1.01-2.68, p = 0.040; OR = 1.60, 95% CI 1.10-2.31, p = 0.012, respectively). In addition, a higher prevalence of CKD was observed in patients with hypertension (OR = 3.49, 95% CI 2.43-5.06, p < 0.001). Underweight patients were more likely to develop AKI (OR = 2.66, 95% CI 1.03-6.08, p = 0.029). Anthracyclines may contribute to a higher risk of AKI, and antimetabolites and immunomodulators may be associated with the development of CKD. Overall, patients with hematological malignancies had significantly higher rates of AKI/CKD than those with solid tumors. Among solid tumor patients, the prevalence of AKI/CKD was low in patients with lung and breast cancer.

CONCLUSIONS

AKI and CKD prevalence varies across cancer types, influenced by factors, such as diabetes, hypertension, body weight, and antitumor drugs. Tailored treatment plans are essential for improving cancer patient outcomes.

Omega-3 polyunsaturated fatty acids protect against cisplatin-induced nephrotoxicity by activating the Nrf2 signaling pathway

Nephrotoxicity is a prevalent side effect observed in patients undergoing chemotherapy. The pathogenesis of chemotherapy-induced nephrotoxicity involves various factors such as oxidative stress, DNA damage, inflammation, and apoptosis. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), possess anti-inflammatory and antioxidant properties. This study investigated the effects of EPA and DHA, either alone or in combination, on cisplatin-induced nephrotoxicity in mice, as well as their underlying mechanisms of action. The combined administration of EPA and DHA demonstrated superior efficacy in mitigating cisplatin-induced nephrotoxicity compared to administration alone, including the reduction of oxidative damage, inflammation, and apoptosis. Moreover, the combination of EPA and DHA suppressed inflammation and prevented the development of chronic kidney fibrosis during prolonged observations following repeated cisplatin administration. Mechanistically, ω-3 PUFAs enhance the expression of antioxidant genes by activating the p62-Keap1-Nrf2 signaling pathway. Furthermore, Nrf2 activation can inhibit the cisplatin-induced p53 apoptosis signal by upregulating the expression of MDM2 in renal tubular epithelial cells. Consequently, ω-3 PUFAs exert a protective effect against cisplatin-induced renal injury through activating the Nrf2 signaling pathway, suggesting that ω-3 PUFAs intake holds promise as a therapeutic strategy for combating cisplatin-induced nephrotoxicity.

Patients' knowledge about renal secondary effects of anti-tumoral drugs and renal protection measures

PURPOSE

Onco-nephrology is an emerging subspecialty aiming to better understand and prevent renal events in cancer patients. We assessed patients' knowledge about (1) oncological/hematological treatments induced renal toxicity and (2) kidney protective measures.

METHODS

Adult patients receiving systemic anti-tumor treatments in multiple day hospital units in France answered a self-administered questionnaire about their knowledge and expectations related to treatment-associated renal toxicity.

RESULTS

In total, 621 questionnaires were collected in 8 units from November 2021 to January 2022. Among respondents, 84.5% were treated for a solid tumor. Overall, 34.3% (n = 208) patients reported they had some knowledge about potential renal adverse events related to their anticancer treatment, and 38.5% (n = 234) about kidney protection measures. Their referring oncologist or hematologist represented the commonest source of knowledge (67.8%). Sufficient hydration was cited as a kidney protection measure by 93.2% (n = 218) of patients declaring some knowledge about renal toxicity; prevention of nausea/vomiting by 52.6% (n = 123). Consumption of still and alkaline water was chosen by respectively 64.4% (n = 400) and 16.8% (n = 104) of participants to correct dehydration. A majority of patients expressed strong interest for receiving more information about renal toxicity and prevention: median Likert scale score was 10/10 (Q1-Q3, 5-10), with online resources mentioned as the most desired source of information.

CONCLUSION

One-third of patients declared they had some knowledge about potential renal toxicity of their oncologic treatment and the ways to prevent them, especially regarding hydration. However, a majority expressed interest for dedicated information, which conducted to the elaboration of free online educational sheets for patients.

Exploring and comparing renal adverse effects between PARP inhibitors based on a real-world analysis of post-marketing surveillance data

Objective

Poly (ADP-ribose) polymerase inhibitors (PARPis) are emerging targeted therapeutic agents in oncology, primarily indicated for ovarian and metastatic breast cancer. Acute kidney injury (AKI) has been observed in patients undergoing PARPi treatment, while there is still a lack of comprehensive comparisons of AKI associated with different PARPis. Our study aimed to extensively characterize the renal adverse effects (RAEs) of PARPi using real-world data.

Methods

Disproportionality analysis and Bayesian analysis were employed for data mining to identify suspected RAE cases after different PARPis use within the Food and Drug Administration's Adverse Event Reporting System from January 2004 to September 2023. The time to onset, fatality, and hospitalization rates of PARPi-related RAEs were also investigated.

Results

We identified 1,696 PARPi-related RAEs, predominantly affecting patients over 85 (56.31%). Veliparib exhibited a more pronounced association with RAEs compared to others, as indicated by the highest reporting odds ratio (ROR = 29.20, 95% CI = 8.79-96.97), proportional reporting ratio (PRR = 19.80, χ2 = 72.62), and empirical Bayes geometric mean (EBGM = 19.80, the lower 90% one-sided CI = 7.25). The median time to RAEs onset was 15 (interquartile range: 6-55.75) days following the initiation of PARPi therapy. PARPi-related RAEs generally led to a 28.15% hospitalization rate and a 4.34% fatality rate.

Conclusion

Although the majority present with reversible creatinine elevation, PARPi-related RAEs merits broader attention, given its potential for clinical consequences. We should strive to early identify those individuals who may have irreversible kidney damage. The focus should be directed toward monitoring renal function in individuals receiving PARPi, especially in senile people and those with a predisposition to AKI.

Paraneoplastic Cast Nephropathy Associated With Pancreatic Acinar Cell Carcinoma: A Kidney Biopsy Teaching Case

Paraneoplastic cast nephropathy, a rare cause of acute kidney injury, is most commonly observed in cases of multiple myeloma and is characterized by the formation of intratubular casts composed of monoclonal light chains. Nonmonoclonal paraneoplastic cast nephropathy has also been reported in patients with pancreatic acinar cell carcinoma or prolactinoma. In this case report, we present a case of polyclonal cast nephropathy in a patient with metastatic acinar cell carcinoma. We aim to emphasize the significance of recognizing this uncommon complication in patients with solid tumors and to discuss the diagnostic challenges and potential pathophysiology of this unique condition.

Effect of acute kidney injury and overall survival in patients with postoperative head and neck cancer who received chemoradiotherapy with cisplatin: A supplementary analysis of the phase II/III trial of JCOG1008

BACKGROUND

In a randomized phase II/III trial (JCOG1008), weekly cisplatin (40 mg/m2) was non-inferior to 3-weekly cisplatin (100 mg/m2) for postoperative high-risk head and neck cancer. We investigated how acute kidney injury (AKI), a major dose-limiting toxicity effect of cisplatin, affects overall survival (OS).

METHODS

We analyzed 251 patients from JCOG1008 receiving chemoradiotherapy. AKI was defined based on AKI Network criteria (serum creatinine increase of ≥0.3 mg/dL or ≥1.5-fold [≥ stage I]) within 30 days after completing chemoradiotherapy. OS in the two arms was compared according to AKI development using the log-rank test.

RESULTS

The total incidence of AKI was lower in the weekly arm than in the 3-weekly arm (38/122 [31.1%] vs. 56/129 [43.4%]). Additionally, stage II/III AKI occurred less frequently in the weekly arm than in the 3-weekly arm (8/122 [6.6%] vs. 19/129 [14.7%]). Cisplatin doses were similar in the weekly arm for patients with and without AKI (median, 238.6 mg/m2 vs. 239.2 mg/m2; p = 0.94), but lower in the 3-weekly arm for those who developed AKI (median, 276.3 mg/m2 vs. 297.4 mg/m2; p = 0.007). In the weekly arm, there was no difference in OS between patients with and without AKI (hazard ratio [HR], 1.06; 95% confidence interval [CI], 0.53 to 2.10). However, in the 3-weekly arm, patients with AKI had poorer OS than those without AKI (HR, 1.83; 95% CI, 1.04 to 3.21).

CONCLUSIONS

In this supplementary analysis of JCOG1008 data, AKI impacted the OS of patients with head and neck cancer undergoing postoperative chemoradiotherapy in the 3-weekly arm but not in the weekly arm. Our results further endorse the utilization of weekly cisplatin at 40 mg/m2 in this setting.

Developing poly(ethylene glycol)-b-poly(β-hydroxybutyrate)-based self-assembling prodrug for the management of cisplatin-induced acute kidney injury

Although β-hydroxybutyrate (BHB), one of the endogenous body ketones, possesses high bioactivities, it is rapidly consumed, metabolized, and eliminated from the body. In this study, we designed new self-assembling nanoparticles that sustainably released BHB to improve bioavailability and evaluated their efficacy in in vivo experiments using rodent animal models. Since poly(β-hydroxybutyrate) [poly(BHB)] is regarded as a polymeric prodrug that is hydrolyzed by endogenous enzymes and releases BHB in a sustained manner, our idea was to engineer hydrophobic poly(BHB) in one of the segments in the amphiphilic block copolymer, of which self-assembles in water to form nanoparticles of tens of nanometers in size (abbreviated as NanoBHB). Here, methoxy-poly(ethylene glycol) was employed as the hydrophilic segment of the block copolymer to stabilize the nanoparticles in aqueous environments, thus enabling NanoBHBs to be administrable both orally and through injection. Experimental results showed that NanoBHB has low toxicity and releases free BHB for an extended period in vitro and in vivo. Moreover, NanoBHB exhibits superior nephroprotective effects in cisplatin-induced acute kidney injury mouse models compared to low-molecular-weight (LMW) sodium BHB, suggesting the potential of NanoBHB as a sustainable release formulation to supply BHB for medicinal applications.

Perioperative Management of Patients with Diabetes and Cancer: Challenges and Opportunities

BACKGROUND

Both diabetes and cancer are major global health issues that are among the leading causes of morbidity and mortality. There is a high prevalence of diabetes among cancer patients, many of whom require a surgical procedure. This review focuses on the operative complications in patients with diabetes and cancer, and the perioperative management of diabetes in cancer patients.

METHODOLOGY

A literature search of articles in English-published between January 2010 and May 2024-was carried out using the databases PubMed, MEDLINE, Google Scholar, and the Cochrane Database of Systematic Reviews. The search primarily focused on the operative complications in patients with diabetes and cancer, and perioperative management strategies.

RESULTS

The relationship between cancer and diabetes is complex; cancer patients have a high risk of developing diabetes, while diabetes is a risk factor for certain cancers. In addition, various cancer therapies can induce or worsen diabetes in susceptible patients. Many individuals with cancer and diabetes require surgery, and due to underlying diabetes, they may have elevated risks for operative complications. Optimal perioperative management for these patients includes managing perioperative glycemia and other comorbid illnesses, adjusting diabetic and cancer treatments, optimizing nutrition, minimizing the duration of fasting, supporting early mobilization, and providing patient education to enable self-management.

CONCLUSIONS

While evidence is limited, optimal perioperative management for patients with both diabetes and cancer is necessary in order to reduce surgical complications. Future studies are needed to develop evidence-informed perioperative strategies and improve outcomes for these patients.

Global burden of anticancer drug-induced acute kidney injury and tubulointerstitial nephritis from 1967 to 2023

This study aims to figure out the worldwide prevalence of anticancer therapy-associated acute kidney injury (AKI) and tubulointerstitial nephritis (TIN) and the relative risk of each cancer drug. We conducted an analysis of VigiBase, the World Health Organization pharmacovigilance database, 1967-2023 via disproportionate Bayesian reporting method. We further categorized the anticancer drugs into four groups: cytotoxic therapy, hormone therapy, immunotherapy, and targeted therapy. Reporting odds ratio (ROR) and information component (IC) compares observed and expected values to investigate the associations of each category of anticancer drugs with AKI and TIN. We identified 32,722 and 2056 reports (male, n = 17,829 and 1,293) of anticancer therapy-associated AKI and TIN, respectively, among 4,592,036 reports of all-drug caused AKI and TIN. There has been a significant increase in reports since 2010, primarily due to increased reports of targeted therapy and immunotherapy. Immunotherapy exhibited a significant association with both AKI (ROR: 8.92; IC0.25: 3.06) and TIN (21.74; 4.24), followed by cytotoxic therapy (7.14; 2.68), targeted therapy (5.83; 2.40), and hormone therapy (2.59; 1.24) for AKI, and by cytotoxic therapy (2.60; 1.21) and targeted therapy (1.54; 0.61) for TIN. AKI and TIN were more prevalent among individuals under 45 years of age, with a female preponderance for AKI and males for TIN. These events were reported in close temporal relationship after initiation of the respective drug (16.53 days for AKI and 27.97 days for TIN), and exhibited a high fatality rate, with 23.6% for AKI and 16.3% for TIN. These findings underscore that kidney-related adverse drug reactions are of prognostic significance and strategies to mitigate such side effects are required to optimize anticancer therapy.

Cancer drugs and acute kidney injury: new therapies and new challenges

PURPOSE OF REVIEW

Cancer therapies continue to evolve at a rapid pace and although novel treatments, including immunotherapies and targeted therapies have allowed for substantial improvements in cancer survival, they carry associated risks of acute kidney injury (AKI). We aim to summarize the existing literature on AKI associated with the spectrum of systemic cancer treatments, including conventional chemotherapies, newer immunotherapies, and the growing number of targeted cancer therapies, which may be associated with both AKI and 'pseudo-AKI'.

RECENT FINDINGS

Conventional cytotoxic chemotherapies (e.g. cisplatin and other platinum-based agents, methotrexate, pemetrexed, ifosfamide, etc.) with well recognized nephrotoxicities (predominantly tubulointerstitial injury) remain in widespread use. Immunotherapies (e.g., immune checkpoint inhibitors and CAR-T therapies) may be associated with kidney immune-related adverse events, most often acute interstitial nephritis, and rarely, glomerular disease. Recently, multiple targeted cancer therapies have been associated with reduced renal tubular secretion of creatinine, causing elevations in serum creatinine and apparent 'pseudo-AKI'. To complicate matters further, these agents have had biopsy-proven, 'true' kidney injury attributed to them in numerous case reports.

SUMMARY

Clinicians in nephrology and oncology must be aware of the various potential kidney risks with these agents and recognize those with clinically meaningful impact on both cancer and kidney outcomes.

A clinical score to predict recovery in end-stage kidney disease due to acute kidney injury

Background

Acute kidney injury (AKI) is a major contributor to end-stage kidney disease (ESKD). About one-third of patients with ESKD due to AKI recover kidney function. However, the inability to accurately predict recovery leads to improper triage of clinical monitoring and impacts the quality of care in ESKD.

Methods

Using data from the United States Renal Data System from 2005 to 2014 (n = 22 922), we developed a clinical score to predict kidney recovery within 90 days and within 12 months after dialysis initiation in patients with ESKD due to AKI. Multivariable logistic regressions were used to examine the effect of various covariates on the primary outcome of kidney recovery to develop the scoring system. The resulting logistic parameter estimates were transformed into integer point totals by doubling and rounding the estimates. Internal validation was performed.

Results

Twenty-four percent and 34% of patients with ESKD due to AKI recovered kidney function within 90 days and 12 months, respectively. Factors contributing to points in the two scoring systems were similar but not identical, and included age, race/ethnicity, body mass index, congestive heart failure, cancer, amputation, functional status, hemoglobin and prior nephrology care. Three score categories of increasing recovery were formed: low score (0-6), medium score (7-9) and high score (10-12), which exhibited 90-day recovery rates of 12%, 26% and 57%. For the 12-month scores, the low, medium and high groups consisted of scores 0-5, 6-8 and 9-11, with 12-month recovery rates of 16%, 33% and 62%, respectively. The internal validation assessment showed no overfitting of the models.

Conclusion

A clinical score derived from information available at incident dialysis predicts renal recovery at 90 days and 12 months in patients with presumed ESKD due to AKI. The score can help triage appropriate monitoring to facilitate recovery and begin planning long-term dialysis care for others.

Single and combination immunotherapy with chemotherapy and the risk of AKI in patients with solid cancer

BACKGROUND AND OBJECTIVES

Acute kidney injury (AKI) has emerged as an important toxicity among patients with advanced cancer treated with immune checkpoint inhibitors. The aim of this study was to describe the incidence, risk factors and mortality of AKI in patients receiving immune checkpoint inhibitors alone or in combination with another form of immunotherapy or chemotherapy.

DESIGN, SETTING AND PARTICIPANTS

We included all patients who received immune checkpoint inhibitors alone or in combination with another form of immunotherapy or chemotherapy at AC Camargo Cancer Center from January 2015 to December 2019. AKI was defined as a ≥ 1.5 fold increase in creatinine from baseline within 12 months of immune checkpoint inhibitor initiation. We assessed the association between baseline demographics, comorbidities, medications and risk of AKI using a competing risk model, considering death as a competing event.

RESULTS

We included 614 patients in the analysis. The mean age was 58.4 ± 13.5 years, and the mean baseline creatinine was 0.8 ± 0.18 mg/dL. AKI occurred in 144 (23.5%) of the patients. The most frequent AKI etiologies were multifactorial (10.1%), hemodynamic (8.8%) and possibly immunotherapy-related (3.6%). The likelihood of AKI was greater in patients with genitourinary cancer (sHR 2.47 95% CI 1.34-4.55 p < 0.01), with a prior AKI history (sHR 2.1 95% CI 1.30-3.39 p < 0.01) and taking antibiotics (sHR 2.85 95% CI 1.54-5.27 p < 0.01).

CONCLUSIONS

In this study, genitourinary cancer, previous AKI and antibiotics use were associated with a higher likelihood of developing AKI.

Tubule-specific cyclin-dependent kinase 12 knockdown potentiates kidney injury through transcriptional elongation defects

Direct tubular injury caused by several medications, especially chemotherapeutic drugs, is a common cause of AKI. Inhibition or loss of cyclin-dependent kinase 12 (CDK12) triggers a transcriptional elongation defect that results in deficiencies in DNA damage repair, producing genomic instability in a variety of cancers. Notably, 10-25% of individuals developed AKI after treatment with a CDK12 inhibitor, and the potential mechanism is not well understood. Here, we found that CDK12 was downregulated in the renal tubular epithelial cells in both patients with AKI and murine AKI models. Moreover, tubular cell-specific knockdown of CDK12 in mice enhanced cisplatin-induced AKI through promotion of genome instability, apoptosis, and proliferative inhibition, whereas CDK12 overexpression protected against AKI. Using the single molecule real-time (SMRT) platform on the kidneys of CDK12RTEC+/- mice, we found that CDK12 knockdown targeted Fgf1 and Cast through transcriptional elongation defects, thereby enhancing genome instability and apoptosis. Overall, these data demonstrated that CDK12 knockdown could potentiate the development of AKI by altering the transcriptional elongation defect of the Fgf1 and Cast genes, and more attention should be given to patients treated with CDK12 inhibitors to prevent AKI.

Severe Acute Kidney Injury in Hospitalized Cancer Patients: Epidemiology and Predictive Model of Renal Replacement Therapy and In-Hospital Mortality

BACKGROUND

Acute kidney injury (AKI) is a common complication among cancer patients, often leading to longer hospital stays, discontinuation of cancer treatment, and a poor prognosis. This study aims to provide insight into the incidence of severe AKI in this population and identify the risk factors associated with renal replacement therapy (RRT) and in-hospital mortality.

METHODS

This retrospective cohort study included 3201 patients with cancer and severe AKI admitted to a Comprehensive Cancer Center between January 1995 and July 2023. Severe AKI was defined according to the KDIGO guidelines as grade ≥ 2 AKI with nephrological in-hospital follow-up. Data were analyzed in two timelines: Period A (1995-2010) and Period B (2011-2023).

RESULTS

A total of 3201 patients (1% of all hospitalized cases) were included, with a mean age of 62.5 ± 17.2 years. Solid tumors represented 75% of all neoplasms, showing an increasing tendency, while hematological cancer decreased. Obstructive AKI declined, whereas the incidence of sepsis-associated, prerenal, and drug-induced AKI increased. Overall, 20% of patients required RRT, and 26.4% died during hospitalization. A predictive model for RRT (AUC 0.833 [95% CI 0.817-0.848]) identified sepsis and hematological cancer as risk factors and prerenal and obstructive AKI as protective factors. A similar model for overall in-hospital mortality (AUC 0.731 [95% CI 0.71-0.752]) revealed invasive mechanical ventilation (IMV), sepsis, and RRT as risk factors and obstructive AKI as a protective factor. The model for hemato-oncological patients' mortality (AUC 0.832 [95% CI 0.803-0.861]) included IMV, sepsis, hematopoietic stem cell transplantation, and drug-induced AKI. Mortality risk point score models were derived from these analyses.

CONCLUSIONS

This study addresses the demographic and clinical features of cancer patients with severe AKI. The development of predictive models for RRT and in-hospital mortality, along with risk point scores, may play a role in the management of this population.

All-cause and immune checkpoint inhibitor-associated acute kidney injury in immune checkpoint inhibitor users: a meta-analysis of occurrence rate, risk factors and mortality

Background

Immune checkpoint inhibitors (ICIs) have been associated with acute kidney injury (AKI). However, the occurrence rate of ICI-related AKI has not been systematically examined. Additionally, exposure to proton pump inhibitors (PPIs) and non-steroidal anti-inflammatory drugs (NSAIDs) were considered as risk factors for AKI, but with inconclusive results in ICI-related AKI. Our aim was to analyse the occurrence rate of all-cause AKI and ICI-related AKI and the occurrence rates of severe AKI and dialysis-requiring AKI, and to determine whether exposure to PPIs and NSAIDs poses a risk for all-cause and ICI-related AKI.

Methods

This study population was adult ICI recipients. A systematic review was conducted by searching MEDLINE, Embase and PubMed through October 2023. We included prospective trials and observational studies that reported any of the following outcomes: the occurrence rate of all-cause or ICI-related AKI, the relationship between PPI or NSAID exposure and AKI development or the mortality rate in the AKI or non-AKI group. Proportional meta-analysis and pairwise meta-analysis were performed. The evidence certainty was assessed using the Grading of Recommendations Assessment, Development and Evaluation framework.

Results

A total of 120 studies comprising 46 417 patients were included. The occurrence rates of all-cause AKI were 7.4% (14.6% from retrospective studies and 1.2% from prospective clinical trials). The occurrence rate of ICI-related AKI was 3.2%. The use of PPIs was associated with an odds ratio (OR) of 1.77 [95% confidence interval (CI) 1.43-2.18] for all-cause AKI and an OR of 2.42 (95% CI 1.96-2.97) for ICI-related AKI. The use of NSAIDs was associated with an OR of 1.77 (95% CI 1.10-2.83) for all-cause AKI and an OR of 2.57 (95% CI 1.68-3.93) for ICI-related AKI.

Conclusions

Our analysis revealed that approximately 1 in 13 adult ICI recipients may experience all-cause AKI, while 1 in 33 adult ICI recipients may experience ICI-related AKI. Exposure to PPIs and NSAIDs was associated with an increased OR risk for AKI in the current meta-analysis.

Kidney Transplantation in Multiple Myeloma and Monoclonal Gammopathy of Renal Significance

Recent advances in the treatment of plasma cell disorders (PCDs) have provided a wealth of therapy alternatives and improved overall survival tremendously. Various types of PCDs are associated with kidney injury and end-stage kidney disease in a considerable number of patients. Kidney transplantation (KTx) is the best option for renal replacement therapy in select patients in terms of both quality of life parameters and overall survival. Even with modern therapies, all PCDs carry the risk of hematologic progression, whereas histologic recurrence and graft loss are other prevailing concerns in these patients. The risk of mortality is also higher in some of these disorders compared with KTx recipients who suffer from other causes of kidney disease. Unlike solid cancers, there is no well-defined "waiting time" after hematologic remission before proceeding to KTx. Thus, clinicians are usually reluctant to recommend KTx to patients who develop end-stage kidney disease due to PCDs. This review aims to provide the current evidence on KTx outcomes in patients with monoclonal gammopathy of renal significance and multiple myeloma. Although immunoglobulin light chain amyloidosis is a monoclonal gammopathy of renal significance subtype, KTx outcomes in this group are mentioned in another chapter of this issue.

Multiple Facets of Multiple Myeloma in Kidney Biopsy: A Multicenter Retrospective Study

Introduction

Multiple myeloma is a type of plasma cell dyscrasia, which causes clonal proliferation of plasma cells and deposition in various organ systems. At presentation, 50% of patients with multiple myeloma have kidney dysfunction, which is considered a poor prognostic indicator. Data on the histopathological manifestations of multiple myeloma are sparse.

Objective

To look at the kidney histopathological lesions in patients with the clinical diagnosis of multiple myeloma.

Materials and Methods

A retrospective analysis of all kidney biopsies in patients with the clinical diagnosis of multiple myeloma was performed from June 1, 2020 to May 30, 2022, from three tertiary care nephrology referral centers.

Results

A total of 61 patients with multiple myeloma and biopsy-proven kidney involvement were included in the study. The mean age at presentation was 55.39 ± 11.91 years, with male predominance (male to female ratio -1.6:1). The most common lesion on kidney biopsy was myeloma cast nephropathy (72.1%), followed by light chain deposition disease (21.3%) and AL amyloidosis (18%). About 26% of patients had dual lesions on kidney biopsy, 3% had three types of lesions on kidney biopsy In 48% of patients, the diagnosis of multiple myeloma was made only after the kidney biopsy.

Conclusion

Patients with multiple myeloma and kidney involvement should be biopsied as the type of histopathological lesion influences the treatment options and prognosis.

Tumor Markers as Predictors of Acute Kidney Injury Incidence and Staging of the Muscle-Invasive Bladder Cancer Receiving Chemoradiation Therapy

Background

Bladder cancer, as one of types of cancers within the urinary tract, is associated with a greater risk of acute kidney injury (AKI), resulting in a poorer prognosis, discontinuation of effective oncological treatments, longer hospitalization, and higher expenses. There is no discussion yet on tumor markers in bladder cancer. With the revolutionary advances in bladder cancer molecular subtyping over the past decade, the presence of tumor markers to assess the staging of bladder cancer has yet to be discussed. In this study, we intended to assess the relationship between tumor markers and incidence of AKI, also between tumor markers and the cancer staging.

Methods

This retrospective cross-sectional study utilized secondary data from 26 medical records of patients diagnosed with bladder cancer at the Adam Malik and Universitas Sumatera Utara Hospital between 2021and 2022. This study included all patients with bladder cancer who met the inclusion criteria. Continuous variables were reported as mean (standard deviation (SD)) and examined using an independent t-test. Categorical variables were reported as proportions, examined using Chi-square or Fisher's exact test. Pre- and post-tumor marker data were evaluated with dependent sample t-test for normal variance data, and Wilcoxon test for data with atypical distribution. P values were set at 0.05.

Results

CD44 (P = 0.003) and programmed cell death 1 (PD-1) (P = 0.030) were the only significant markers in their pre- and post-chemoradiation states among the four investigated tumor markers in this study. Meanwhile, PD-1 tumor marker levels were only found to be significant between AKI and pre-chemoradiation (P = 0.011). Even though the multivariate study of tumor staging did not show any statistical significance, both tumor markers CD44 and PD-1 showed a significant effect on the incidence of acute renal damage (P = 0.034).

Conclusions

Pre-chemoradiation PD-1 tumor markers showed promise as good predictive indicators for staging and AKI incidence in muscle-invasive bladder cancer patients undergoing chemoradiation therapy.

Chapter 1: Evaluation of kidney function in patients undergoing anticancer drug therapy, from clinical practice guidelines for the management of kidney injury during anticancer drug therapy 2022

The prevalence of CKD may be higher in patients with cancer than in those without due to the addition of cancer-specific risk factors to those already present for CKD. In this review, we describe the evaluation of kidney function in patients undergoing anticancer drug therapy. When anticancer drug therapy is administered, kidney function is evaluated to (1) set the dose of renally excretable drugs, (2) detect kidney disease associated with the cancer and its treatment, and (3) obtain baseline values for long-term monitoring. Owing to some requirements for use in clinical practice, a GFR estimation method such as the Cockcroft-Gault, MDRD, CKD-EPI, and the Japanese Society of Nephrology's GFR estimation formula has been developed that is simple, inexpensive, and provides rapid results. However, an important clinical question is whether they can be used as a method of GFR evaluation in patients with cancer. When designing a drug dosing regimen in consideration of kidney function, it is important to make a comprehensive judgment, recognizing that there are limitations regardless of which estimation formula is used or if GFR is directly measured. Although CTCAEs are commonly used as criteria for evaluating kidney disease-related adverse events that occur during anticancer drug therapy, a specialized approach using KDIGO criteria or other criteria is required when nephrologists intervene in treatment. Each drug is associated with the different disorders related to the kidney. And various risk factors for kidney disease associated with each anticancer drug therapy.

The risk of acute kidney injury in colorectal cancer survivors: an english population-based matched cohort study

BACKGROUND

Colorectal cancer survival has improved in recent decades but there are concerns that survivors may develop kidney problems due to adverse effects of cancer treatment or complications of the cancer itself. We quantified the risk of acute kidney injury (AKI) in colorectal cancer survivors compared to people with no prior cancer.

METHODS

Retrospective matched cohort study using electronic health record primary care data from the Clinical Practice Research Datalink GOLD linked to hospital data in England (HES-APC). Individuals with colorectal cancer between 1997-2018 were individually matched on age, sex, and GP practice to people with no prior cancer. We used Cox models to estimate hazard ratios for an incident hospital diagnosis of AKI in colorectal cancer survivors compared to individuals without cancer, overall and stratified by time since diagnosis adjusted for other individual-level factors (adj-HR).

RESULTS

Twenty thousand three hundred forty colorectal cancer survivors were matched to 100,058 cancer-free individuals. Colorectal cancer survivors were at increased risk of developing AKI compared to people without cancer (adj-HR = 2.16; 95%CI 2.05-2.27). The HR was highest in the year after diagnosis (adj-HR 7.47, 6.66-8.37), and attenuated over time, but there was still increased AKI risk > 5 years after diagnosis (adj-HR = 1.26, 1.17-1.37). The association between colorectal cancer and AKI was greater for younger people, men, and those with pre-existing chronic kidney disease.

CONCLUSIONS

Colorectal cancer survivors were at increased risk of AKI for several years after cancer diagnosis, suggesting a need to prioritise monitoring, prevention, and management of kidney problems in this group of cancer survivors.

Kidney and Cancer Outcomes with Standard Versus Alternative Chemotherapy Regimens for First-Line Treatment of Metastatic Urothelial Carcinoma

Key Points

Many patients with metastatic urothelial carcinoma are deemed cisplatin-ineligible because of reduced kidney function. Options include split-dose cisplatin or carboplatin. There was no significant association between regimen type and AKI. Alternative regimens were associated with higher risk of progressive disease. There is a need to revisit cisplatin eligibility criteria and develop strategies to optimize cancer treatment for patients with CKD.

Background

Cisplatin-based chemotherapy regimens remain the optimal first-line treatment for patients with metastatic urothelial carcinoma (mUC). However, many patients are deemed cisplatin-ineligible, predominantly because of reduced kidney function. Other treatment options include split-dose cisplatin, carboplatin, and non–platinum-based regimens. We compared the incidence of AKI and cancer outcomes within three chemotherapy regimens.

Methods

We conducted a single-center retrospective study of patients with mUC who received first-line chemotherapy from 2005 to 2019. We compared standard gemcitabine–cisplatin (gem-cis) with two alternative regimens: (1 ) gem-cis split-dose regimen (split) with cisplatin divided over days 1 and 8 and (2 ) combination of gemcitabine–carboplatin or single-agent gemcitabine (gem/gem-carbo). The primary outcome was Kidney Disease Improving Global Outcomes–defined AKI. Secondary outcomes included overall survival and progression-free survival.

Results

We identified 183 patients (98 gem-cis, 32 split, and 53 gem/gem-carbo). Median baseline eGFR in the gem/cis group was 78 ml/min per 1.73 m2 (interquartile range, 66–91), in the split group 64 (48–77), and in the gem/gem-carbo 45 (33–57). There was no significant association between regimen type and incidence of AKI when adjusted for age, Eastern Cooperative Oncology Group, baseline eGFR, hypertension, diabetes, and visceral disease. The adjusted hazard ratios were 1.31 (95% confidence interval [CI], 0.61 to 2.78; P = 0.49) and 0.98 (95% CI, 0.46 to 2.07; P = 0.95) for split and gem/gem-carbo groups, respectively, versus gem-cis. Split and gem/gem-carbo regimens were associated with higher mortality and progressive disease relative to gem-cis with an adjusted hazard ratio of 1.54 (95% CI, 1.02 to 2.33; P = 0.04) and 1.96 (95% CI, 1.31 to 2.95; P < 0.01), respectively. Median progression free survival was 8.1 (interquartile range, 4.6–14.8), 6.1 (4.1–9.3), and 4.4 (2.3–8.6) months in the gem-cis, split, and gem/gem-carbo groups.

Conclusions

There was no significant difference in the incidence of AKI between the three regimens studied. However, standard gem-cis was associated with improved cancer outcomes. Novel regimens and kidney protective strategies are needed for patients with mUC with kidney disease.

Onco-Nephrology: Kidney Disease in the Cancer Patient

Patients with cancer may develop kidney disease with a variety of different clinical manifestations including acute kidney injury, chronic kidney disease, hypertension, proteinuria and electrolyte disturbances. Onco-nephrology is the subspecialty of nephrology that diagnoses and manages kidney disease in patients with cancer. In this article, we review major topics in Onco-Nephrology that may be encountered by the general internist.

Onco-nephrology: Physicians' Expectations About a New Subspecialty

INTRODUCTION

Renal events are common in cancer patients and malignancy is a prevalent complication in both patients transplanted and under kidney replacement therapy (KRT). In recent years, onco-nephrology has been developed as a subspecialty whose scope has not been well established yet. The aim of our study was to assess resident and senior physicians' knowledge and expectations about onco-nephrology.

METHODS AND MATERIALS

Two anonymous self-administered online questionnaires were developed by a multidisciplinary team and distributed to French residents and senior physicians.

RESULTS

Two hundred twenty-eight physicians answered the survey, including 128 (56%) nephrologists, of which 98 (43%) were senior physicians and 130 (57%) were residents. Nephrologists rated their confidence in their ability to face onco-nephrological situation at 6/10 (interquartile range (IQR) 4.0-7.0) and oncologists at 6.0/10 (5.0-7.0). Managing cancer drugs in patients on KRT or in transplanted patients and discussion about introducing dialysis in cancer patients were designated as the most challenging topics. Asking if they had received appropriate learning, residents' median agreement was ranked at 3.0/10 (2.0-4.0). Forty-six percent of the respondents considered available resources as not appropriate. Specialized onco-nephrology consultations were accessible for 21% of the respondents. Finally, respondents thought there is a strong need for a national working group (8.3/10) with 87% of them expecting new reliable guidelines.

CONCLUSION

The present survey revealed physicians' expectations about onco-nephrology implementation in France. An appropriate answer could be the creation of a national working group. Therefore, GRIFON (Groupe de Recherche Interdisciplinaire en OncoNéphrologie) has recently been created.

Immunotherapy in oncology and the kidneys: a clinical review of the evaluation and management of kidney immune-related adverse events

Immune checkpoint inhibitors (ICI) are now widely used in the treatment of many cancers, and currently represent the standard of care for multiple malignancies. These agents enhance the T cell immune response to target cancer tissues, and have demonstrated considerable benefits for cancer outcomes. However, despite these improved outcomes, there are important kidney immune-related adverse events (iRAEs) associated with ICI. Acute tubulo-interstitial nephritis remains the most frequent kidney iRAE, however glomerular lesions and electrolytes disturbances are increasingly being recognized and reported. In this review, we summarize clinical features and identify risk factors for kidney iRAEs, and discuss the current understanding of pathophysiologic mechanisms. We highlight the evidence basis for guideline-recommended management of ICI-related kidney injury as well as gaps in current knowledge. We advocate for judicious use of kidney biopsy to identify ICI-associated kidney injury, and early use of corticosteroid treatment where appropriate. Selected patients may also be candidates for re-challenge with ICI therapy after a kidney iRAE, in view of current data on recurrent rates of kidney injury. Risk of benefits of re-challenge must be considered on an individual considering patient preferences and prognosis. Lastly, we review current knowledge of ICI use in the setting of patients with end-stage kidney disease, including kidney transplant recipients and those receiving dialysis, which suggest that these patients should not be summarily excluded from the potential benefits of these cancer therapies.

Immune Checkpoint Inhibitor-Associated Nephrotoxicity

CONTEXT

The clinical indications for immune checkpoint inhibitors (ICIs) are rapidly expanding. However, adverse events affecting multiple organs, including kidneys leading to ICI-associated acute kidney injury (AKI), remain a significant challenge with ICI therapy. Although AKI is considered a rare complication, it can be severe and result in treatment interruption or discontinuation of ICIs. Despite a generally favorable kidney prognosis, the possibility of re-challenging ICI therapy remains a subject of debate, particularly for patients who have exhausted other treatment options or experienced severe AKI. Subject of Review: In a recent review article, Sprangers et al. provide a comprehensive overview of the possible mechanisms and clinical manifestations of ICI-associated AKI [Nat Rev Nephrol. 2022;18(12):794-805]. The authors propose a practical strategy for diagnosing and managing suspected cases of ICI-associated AKI, which includes identifying a subset of eligible patients who may be re-exposed to ICIs following an episode of AKI. Second Opinion: The authors of the review article offer several recommendations on the diagnosis and treatment of ICI-associated nephrotoxicity. While we generally agree with the recommendations proposed by the authors, it is important to acknowledge that the available data primarily rely on small retrospective studies, as the authors have recognized. In addition, there are two key questions that need be carefully addressed in future studies: (1) the optimal dose and duration of corticosteroids and the use of alternative immunosuppressive agents in patients with ICI-associated nephrotoxicity and (2) a clear guideline for restarting ICI treatment in patients with AKI who have not fully recovered their kidney function.

Immune Checkpoint Inhibitor-Associated AKI: Debates in Diagnosis, Management, and Rechallenge

Immune checkpoint inhibitors (ICIs) are now established treatments for advanced cancer and their use is now ubiquitous. The high upside of ICIs is tempered by their toxicity profile affecting almost every organ, including the kidneys. Although acute interstitial nephritis is the major kidney-related adverse effect of checkpoint inhibitors, other manifestations such as electrolyte abnormalities and renal tubular acidosis have been described. With increasing awareness and recognition of these events, the focus has shifted to non-invasive identification of ICI-acute interstitial nephritis, with sophisticated approaches involving biomarkers and immunologic signatures being studied. Although the management of immune-related adverse events with corticosteroids is straightforward, there now are more data to help guide immunosuppressive regimens, ICI rechallenge, and delineate risk and efficacy in special populations such as individuals on dialysis or those who have received a transplant.

Malignancy diseases and kidneys: A nephrologist prospect and updated review

Acute kidney injury (AKI), chronic renal failure, and tubular abnormalities represent the kidney disease spectrum of malignancy. Prompt diagnosis and treatment may prevent or reverse these complications. The pathogenesis of AKI in cancer is multifactorial. AKI affects outcomes in cancer, oncological therapy withdrawal, increased hospitalization rate, and hospital stay. Renal function derangement can be recovered with early detection and targeted therapy of cancers. Identifying patients at higher risk of renal damage and implementing preventive measures without sacrificing the benefits of oncological therapy improve survival. Multidisciplinary approaches, such as relieving obstruction, hydration, etc., are required to minimize the kidney injury rate. Different keywords, texts, and phrases were used to search Google, EMBASE, PubMed, Scopus, and Google Scholar for related original and review articles that serve the article's aim well. In this nonsystematic article, we aimed to review the published data on cancer-associated kidney complications, their pathogenesis, management, prevention, and the latest updates. Kidney involvement in cancer occurs due to tumor therapy, direct kidney invasion by tumor, or tumor complications. Early diagnosis and therapy improve the survival rate. Pathogenesis of cancer-related kidney involvement is different and complicated. Clinicians' awareness of all the potential causes of cancer-related complications is essential, and a kidney biopsy should be conducted to confirm the kidney pathologies. Chronic kidney disease is a known complication in malignancy and therapies. Hence, avoiding nephrotoxic drugs, dose standardization, and early cancer detection are mandatory measures to prevent renal involvement.

The Onco-Nephrology Field: The Role of Personalized Chemotherapy to Prevent Kidney Damage

In recent years, the onco-nephrology field has acquired a relevant role in internal medicine due to the growing number of cases of renal dysfunction that have been observed in cancer patients. This clinical complication can be induced by the tumor itself (for example, due to obstructive phenomena affecting the excretory tract or by neoplastic dissemination) or by chemotherapy, as it is potentially nephrotoxic. Kidney damage can manifest as acute kidney injury or represent a worsening of pre-existing chronic kidney disease. In cancer patients, physicians should try to set preventive strategies to safeguard the renal function, avoiding the concomitant use of nephrotoxic drugs, personalizing the dose of chemotherapy according to the glomerular filtration rate (GFR) and using an appropriate hydration therapy in combination with nephroprotective compounds. To prevent renal dysfunction, a new possible tool useful in the field of onco-nephrology would be the development of a personalized algorithm for the patient based on body composition parameters, gender, nutritional status, GFR and genetic polymorphisms.

Incidence of acute kidney injury and decreased estimated glomerular filtration rate according to the site of cancer

BACKGROUND

The epidemiology of renal impairment in patients with cancer remains unclear. We aimed to clarify associations between various cancer sites and renal impairment.

METHODS

We reviewed data from 5674 patients aged ≥ 18 years receiving cancer treatment at a single hospital facility. The primary endpoints were the occurrence of acute kidney injury (AKI), a 30% decrease in the estimated glomerular filtration rate (eGFR), or death. Survival time was defined as the time from study enrolment to AKI occurrence. Kaplan-Meier and Cox proportional hazard analyses were performed.

RESULTS

Hazard ratios (HRs) for AKI occurrence and a ≥ 30% decline in eGFR were significantly higher for kidney, urinary tract, pancreatic, liver, and gallbladder cancers than for colon cancer. Compared with colon cancer, digestive tract cancer showed a significantly higher HR for AKI occurrence alone. The HRs for a ≥ 30% decline in eGFR were significantly higher for patients aged 71‒77 years or ≥ 78 years than for those aged < 68 years, and for patients with eGFR ≥ 90 mL/min/1.73 m² or 30-44 mL/min/1.73 m² than for those with eGFR = 45‒59 mL/min/1.73 m².

CONCLUSIONS

Kidney, urinary, hepatobiliary, or pancreatic cancer are associated with a higher risk of AKI development and eGFR decrease than other cancers. Renal function changes should be more closely monitored in patients with these cancers.

Meta-analysis of cancer risk among end stage renal disease undergoing maintenance dialysis

Currently, there is no consensus on whether maintenance dialysis increases cancer risk in patients with end-stage renal disease (ESRD). Therefore, this study was to systematically evaluate the risk of cancer among ESRD patients undergoing maintenance dialysis. Related studies on the impact of maintenance dialysis on cancer risk were retrieved from PubMed, Embase, Cochrane Library, and other databases from their respective inceptions to 19 February 2021. ESRD patients receiving maintenance dialysis were classified into cancer including non-melanoma skin cancer (NMSC) and cancer excluding NMSC. Standardized incidence ratio (SIR) with its 95% confidence interval (95% CI) was calculated to assess cancer risk. Fourteen studies were included in the meta-analysis. The risk of cancer in patients undergoing maintenance dialysis (with or without NMSC) was significantly higher than controls both in cancer including NMSC (SIR = 1.38, 95% CI: 1.27-1.49, P < 0.001) and cancer excluding NMSC (SIR = 1.34, 95% CI: 1.23-1.47, P < 0.001). Subgroup results identified the higher risk of cancer incidence in both men and women receiving maintenance dialysis. Meanwhile, elevated excess risks were observed among patients with younger age and shorter follow-up time (P < 0.001). Meanwhile, the combined SIR of bladder, cervix, colorectum, kidney, liver, thyroid, tongue, and other cancers were all increased (P < 0.05). ESRD patients undergoing dialysis has higher risk of cancer.

Machine learning for acute kidney injury: Changing the traditional disease prediction mode

Acute kidney injury (AKI) is a serious clinical comorbidity with clear short-term and long-term prognostic implications for inpatients. The diversity of risk factors for AKI has been recognized in previous studies, and a series of predictive models have been developed using traditional statistical methods in conjunction with its preventability, but they have failed to meet the expectations in limited clinical applications, the rapid spread of electronic health records and artificial intelligence machine learning technology has brought new hope for the construction of AKI prediction models. In this article, we systematically review the definition and classification of machine learning methods, modeling ideas and evaluation methods, and the characteristics and current status of modeling studies. According to the modeling objectives, we subdivided them into critical care medical setting models, all medical environment models, special surgery models, special disease models, and special nephrotoxin exposure models. As the first review article to comprehensively summarize and analyze machine learning prediction models for AKI, we aim to objectively describe the advantages and disadvantages of machine learning approaches to modeling, and help other researchers more quickly and intuitively understand the current status of modeling research, inspire ideas and learn from experience, so as to guide and stimulate more research and more in-depth exploration in the future, which will ultimately provide greater help to improve the overall status of AKI diagnosis and treatment.

Exploration of chemotherapy-free regimen after multi-line chemotherapy-induced renal impairment in recurrent ovarian cancer: Case report and literature review

Introduction

Platinum-based combination chemotherapy is recommended first choice for relapsed ovarian cancer. However, many of the chemotherapeutic agents are nephrotoxic and can promote kidney dysfunction, which affect the efficacy of cancer treatment and the survival of the patient. There is a need to explore long-term treatments of chemotherapy-free regimen of chronic kidney disease in recurrent ovarian cancer.

Case presentation

A 41-year-old female patient was presented with stage IIIC well-differentiated ovarian serous papillary adenocarcinoma in 2009. The patient had recurrence of platinum resistance after secondary cytoreductive surgery, and it was difficult to continue chemotherapy after multiple lines of chemotherapy due to myelosuppression, renal impairment and other factors. The patient accepted Niraparib-based treatment regimen after multi-line chemotherapy-induced stage 4 chronic kidney disease. Niraparib combined with anlotinib achieved median PFS of 11 months, disease re-progression, and the patient was switched to niraparib combined with letrozole from October 2021. No evidence of tumor progression was observed till date and the renal toxicity is acceptable.

Conclusions

In patients with relapsed ovarian cancer, treatment becomes increasingly challenging to subsequent therapies because of renal impairment and emerging drug resistance. Niraparib-based treatment regimen may be a good choice for patients with well-differentiated serous adenocarcinoma of the ovary who are intolerant to chemotherapy.

Comparative risk of acute kidney injury among cancer patients treated with immune checkpoint inhibitors

With the development and introduction of immune checkpoint inhibitors (ICIs) in cancer patients, immune-related side effects have increasingly attracted attention. However, the risks of immune-related renal toxicity are poorly characterized. In this study, we performed a network meta-analysis (NMA) of ICI-related randomized clinical trials (RCTs) to elucidate the comparative risk of acute kidney injury (AKI) in cancer patients receiving different ICIs. We also sought to identify other factors potentially affecting the risk of AKI. PubMed and EMBASE were searched for peer-reviewed trial reports published between January 2000 and May 2021. Eligible studies were RCTs studying ICIs in cancer patients and reporting AKI data. We performed a frequentist NMA to evaluate the risk ratios for grade 1-5 and grade 3-5 AKI between the treatment groups. We also assessed the absolute incidence of AKI in the ICI-containing arm using traditional direct meta-analysis. Once significant heterogeneity was detected in a traditional direct meta-analysis, multivariable meta-regression analysis was applied to identify factors that significantly affected the absolute incidence of AKI. A total of 85 RCTs were included in this study. In the NMA for the risk of grade 1-5 and 3-5 AKI, ipilimumab showed a significantly higher risk than avelumab and durvalumab, whereas 1 mg/kg nivolumab plus 3 mg/kg ipilimumab (N1I3) showed a significantly higher risk than other groups. In terms of treatment ranking, durvalumab ± low-dose tremelimumab and avelumab were consistently among the top three safest treatments for grade 1-5 or 3-5 AKI, whereas N1I3, ipilimumab and tremelimumab were consistently among the top three treatments with the highest risk for grade 1-5 or 3-5 AKI. Compared with other cancers, renal cell carcinoma and urothelial carcinoma showed a significantly higher risk of AKI. The incidence of AKI was significantly higher with ICI+chemotherapy than with ICI monotherapy. In this NMA involving large-scale up-to-date ICI trials, we demonstrated the comparative safety of existing ICI drugs for grade 1-5 and grade 3-5 AKI. Based on data from the ICI arms of these trials, we also revealed several potential risk factors for immune-related AKI, including tumor type and treatment paradigm.

KIdney aNd blooD prESsure ouTcomes in Childhood Cancer Survivors: Description of Clinical Research Protocol of the KINDEST-CCS Study

Background

Approximately 30% of childhood cancer survivors (CCSs) will develop chronic kidney disease (CKD) or hypertension 15 to 20 years after treatment ends. The incidence of CKD and hypertension in the 5-year window after cancer therapy is unknown. Moreover, extent of monitoring of CCS with CKD and associated complications in current practice is underexplored. To inform the development of new and existing care guidelines for CCS, the epidemiology and monitoring of CKD and hypertension in the early period following cancer therapy warrants further investigation.

Objective

To describe the design and methods of the KIdney aNd blooD prESsure ouTcomes in Childhood Cancer Survivors study, which aims to evaluate the burden of late kidney and blood pressure outcomes in the first ~10 years after cancer therapy, the extent of appropriate screening and complications monitoring for CKD and hypertension, and whether patient, disease/treatment, or system factors are associated with these outcomes.

Design

Two distinct, but related studies; a prospective cohort study and a retrospective cohort study.

Setting

Five Ontario pediatric oncology centers.

Patients

The prospective study will involve 500 CCS at high risk for these late effects due to cancer therapy, and the retrospective study involves 5,000 CCS ≤ 18 years old treated for cancer between January 2008 and December 2020.

Measurements

Chronic kidney disease is defined as Estimated glomerular filtration rate <90 mL/min/1.73 m² or albumin-to-creatinine ratio ≥ 3mg/mmol. Hypertension is defined by 2017 American Academy of Pediatrics guidelines.

Methods

Prospective study: we aim to investigate CKD and hypertension prevalence and the extent to which they persist at 3- and 5-year follow-up in CCS after cancer therapy. We will collect detailed biologic and clinical data, calculate CKD and hypertension prevalence, and progression at 3- and 5-years post-therapy. Retrospective study: we aim to investigate CKD and hypertension monitoring using administrative and health record data. We will also investigate the validity of CKD and hypertension administrative definitions in this population and the incidence of CKD and hypertension in the first ~10 years post-cancer therapy. We will investigate whether patient-, disease/treatment-, or system-specific factors modify these associations in both studies.

Limitations

Results from the prospective study may not be generalizable to non-high-risk CCS. The retrospective study is susceptible to surveillance bias.

Conclusions

Our team and knowledge translation plan is engaging patient partners, researchers, knowledge users, and policy group representatives. Our work will address international priorities to improve CCS health, provide the evidence of new disease burden and practice gaps to improve CCS guidelines, implement and test revised guidelines, plan trials to reduce CKD and hypertension, and improve long-term CCS health.

Acute Kidney Injury in Critically Ill Patients with Cancer

Advances in cancer therapy have significantly improved overall patient survival; however, AKI remains a common complication in patients with cancer, occurring in anywhere from 11% to 22% of patients, depending on patient-related or cancer-specific factors. Critically ill patients with cancer as well as patients with certain malignancies (e.g., leukemias, lymphomas, multiple myeloma, and renal cell carcinoma) are at highest risk of developing AKI. AKI may be a consequence of the underlying malignancy itself or from the wide array of therapies used to treat it. Cancer-associated AKI can affect virtually every compartment of the nephron and can present as subclinical AKI or as overt acute tubular injury, tubulointerstitial nephritis, or thrombotic microangiopathy, among others. AKI can have major repercussions for patients with cancer, potentially jeopardizing further eligibility for therapy and leading to greater morbidity and mortality. This review highlights the epidemiology of AKI in critically ill patients with cancer, risk factors for AKI, and common pathologies associated with certain cancer therapies, as well as the management of AKI in different clinical scenarios. It highlights gaps in our knowledge of AKI in patients with cancer, including the lack of validated biomarkers, as well as evidence-based therapies to prevent AKI and its deleterious consequences.

Peptides GWN and GW protect kidney cells against Dasatinib induced mitochondrial injury in a SIRT1 dependent manner

Dasatinib, a small-molecule drug used as a treatment for chronic myeloid leukemia induces mitochondrial damage in embryonic kidney (293 T) cells (p < 0.05). This dasatinib induced mitochondrial injury in kidney cells was mitigated by H3K36me3 activating ovotransferrin-derived peptides GWN and GW. Pre-treatment of kidney cells with GWN and GW lead to elevation of cytoprotective sirtuins, SIRT1 and SIRT3, in response to dasatinib injury (p < 0.01) in vitro. Both peptides, GWN and GW, also reversed dasatinib induced the loss of mitochondria in kidney cells and promoted the protein expression of COX4 (p < 0.01). Mechanistically, loss of SIRT1 in kidney cells abolished the ability of GWN and GW to protect embryonic kidney cells against dasatinib injury in vitro. Overall, we provide cell based evidence showing that GWN and GW exhibit the ability to protect mitochondria against dasatinib-induced mitochondrial damage in a SIRT1 dependent manner.

Kidney Biopsy in Patients with Cancer along the Last Decade: A Multicenter Study

Background: Currently, following the new advances in cancer treatments and the increasing prevalence of kidney disease in the population, more kidney biopsies are being performed. The aim of our study is to analyze clinical and histological characteristics of patients with active solid organ malignancy who underwent kidney biopsy. This is a multi-center collaborative retrospective study supported by groups GLOSEN/Onconephrology from the Spanish Society of Nephrology. Clinical, demographical and histological data were collected. Results: A total of 148 patients with cancer who underwent a kidney biopsy from 12 hospitals were included. 64.3% men and mean age of 66.9 years old. The indications for biopsy were acute renal injury (67.1%), proteinuria (17.1%), exacerbated chronic kidney disease (8.2%), and chronic kidney disease (7.5%). Most frequent malignances were lung (29.1%) and abdominal (25%), with 49.7% metastatic cancer. As oncospecific treatment, 28% received chemotherapy, 29.3% immunotherapy, 19.3% specific therapies, and 2.1% conservative treatment. At the time of kidney biopsy, median creatinine was of 2.58 mg/dL [1.81–4.1 (IQ 25–75)], median urine protein-to-creatinine ratio of 700 mg/g [256–2463 (IQ 25–75)] and 53.1% presented hematuria. The most frequent renal biopsy diagnoses were: acute interstitial nephritis (39.9%), acute tubular necrosis (8.8%), IgA nephropathy (7.4%) and membranous nephropathy (6.1%). Median follow-up was 15.2 months [5.7–31.4 (IQ 25–75)]. Conclusions: There is a new trend in kidney disease and cancer patients in terms of diagnosis and treatment. Acute interstitial nephritis has established itself as the most common kidney injury in patients with cancer who underwent a kidney biopsy. Renal biopsy is a valuable tool for diagnosis, treatment, and prognosis of solid organ cancer patients with kidney damage.

Nephrotoxicity in cancer treatment: An update

It has been estimated that nearly 80% of anticancer drug-treated patients receive potentially nephrotoxic drugs, while the kidneys play a central role in the excretion of anticancer drugs. Nephrotoxicity has long been a serious complication that hampers the effectiveness of cancer treatment and continues to influence both mortality and length of hospitalization among cancer patients exposed to either conventional cytotoxic agents or targeted therapies. Kidney injury arising from anticancer drugs tends to be associated with preexisting comorbidities, advanced cancer stage, and the use of concomitant non-chemotherapeutic nephrotoxic drugs. Despite the prevalence and impact of kidney injury on therapeutic outcomes, the field is sorely lacking in an understanding of the mechanisms driving cancer drug-induced renal pathophysiology, resulting in quite limited and largely ineffective management of anticancer drug-induced nephrotoxicity. Consequently, there is a clear imperative for understanding the basis for nephrotoxic manifestations of anticancer agents for the successful management of kidney injury by these drugs. This article provides an overview of current preclinical research on the nephrotoxicity of cancer treatments and highlights prospective approaches to mitigate cancer therapy-related renal toxicity.

Association between chronic kidney disease and cancer including the mortality of cancer patients: national health and nutrition examination survey 1999-2014

PURPOSE

This study aimed to investigate the association between chronic kidney disease (CKD) and different types of cancer and the effect of CKD on mortality among types of cancer.

METHODS

30559 participants from NHANES 1999-2014 were included in our analysis, which had 2824 participants with cancer. Subgroups were grouped by cancer location. The association of different types of cancer with CKD was assessed using logistic regression models. Kaplan-Meier estimates and Cox proportional hazards models were used to evaluate the correlation between CKD and all-cause mortality in different cancer groups.

RESULTS

Age, gender, race, education level, income level, hypertension, diabetes, smoking status, alcohol consumption, TG, HDL-C, UA and eGFR were significantly different between the cancer and non-cancer group. The three cancers with highest prevalence of CKD were kidney cancer (72.3%), bladder cancer (54.7%), and colon cancer (43.0%) in this study. The prevalence of CKD was higher in cancer patients compared to non-cancer ones. Only genitourinary cancer showed a positive association with CKD (OR=1.23, 95% CI: 1.05-1.44) after adjusting for confounding factors. However, CKD was an independent risk factor for mortality from cancer regardless of the type of cancer.

CONCLUSION

CKD is significantly associated only with genitourinary cancer among different types of cancer. CKD is an independent risk factor for survival in cancer patients, regardless of the type of cancer. Monitoring and maintaining the renal function of cancer patients is essential for prolonging their life.

Molecular Mechanisms and Biomarkers Associated with Chemotherapy-Induced AKI

Acute kidney injury (AKI) is a life-threatening condition characterized by a rapid and transient decrease in kidney function. AKI is part of an array of conditions collectively defined as acute kidney diseases (AKD). In AKD, persistent kidney damage and dysfunction lead to chronic kidney disease (CKD) over time. A variety of insults can trigger AKI; however, chemotherapy-associated nephrotoxicity is increasingly recognized as a significant side effect of chemotherapy. New biomarkers are urgently needed to identify patients at high risk of developing chemotherapy-associated nephrotoxicity and subsequent AKI. However, a lack of understanding of cellular mechanisms that trigger chemotherapy-related nephrotoxicity has hindered the identification of effective biomarkers to date. In this review, we aim to (1) describe the known and potential mechanisms related to chemotherapy-induced AKI; (2) summarize the available biomarkers for early AKI detection, and (3) raise awareness of chemotherapy-induced AKI.

Incidence and Risk Factors for Acute Kidney Injury after Allogeneic Stem Cell Transplantation: A Prospective Study

(1) Background: Acute kidney injury (AKI) is a serious complication of hematopoietic stem cell transplantation (HSCT). (2) Methods: The aim was to identify the incidence, severity, and risk factors for AKI during the first 100 days after allo-HSCT; we performed a prospective observational study on 135 consecutive patients. (3) Results: The mean age was 38.3 ± 11.9 years (50.6% females), AKI developed in 93 patients (68.9%), the median time of appearance was 28 days, and the mean serum creatinine at the time of AKI was 1.8 ± 0.8 mg/dL. A total of 36 (38.7%) patients developed stage 1 AKI, 33 (35.5%) patients developed stage 2, and 24 (25.8%) patients developed stage 3; eight (8.6%) patients required temporary hemodialysis, and the mortality rate in these patients was 87.5%. Death was twice as frequent in the AKI subgroup, without statistical significance. Cyclosporine overdose (HR = 2.36, 95% CI: 1.45-3.85, p = 0.001), tacrolimus overdose (HR = 4.72, 95% CI: 2.22-10.01, p < 0.001), acute graft-versus-host disease (aGVHD) (HR = 1.96, 95% CI: 1.13-3.40, p = 0.01), and CRP level (HR = 1.009, 95% CI: 1.007-1.10, p < 0.001) were independent risk factors for AKI. Sepsis (HR = 5.37, 95% CI: 1.75-16.48, p = 0.003) and sinusoidal obstruction syndrome (HR = 5.10, 95% CI: 2.02-12.85, p = 0.001) were found as independent risk factors for AKI stage 3. (4) Conclusions: AKI occurs with high incidence and increased severity after allo-HSCT. Careful monitoring of calcineurin inhibitors and proper management of sepsis may reduce this risk.

Chronic kidney disease and its health-related factors: a case-control study

BACKGROUND

Chronic kidney disease (CKD) is a non-communicable disease that includes a range of different physiological disorders that are associated with abnormal renal function and progressive decline in glomerular filtration rate (GFR). This study aimed to investigate the associations of several behavioral and health-related factors with CKD in Iranian patients.

METHODS

A hospital-based case-control study was conducted on 700 participants (350 cases and 350 controls). Logistic regression was applied to measure the association between the selected factors and CKD.

RESULTS

The mean age of cases and controls were 59.6 ± 12.4 and 58.9 ± 12.2 respectively (p = 0.827). The results of multiple logistic regression suggested that many factors including low birth weight (OR yes/no = 4.07, 95%CI: 1.76-9.37, P = 0.001), history of diabetes (OR yes/no = 3.57, 95%CI: 2.36-5.40, P = 0.001), history of kidney diseases (OR yes/no = 3.35, 95%CI: 2.21-5.00, P = 0.001) and history of chemotherapy (OR yes/no = 2.18, 95%CI: 1.12-4.23, P = 0.02) are associated with the risk of CKD.

CONCLUSIONS

The present study covered a large number of potential risk/ preventive factors altogether. The results highlighted the importance of collaborative monitoring of kidney function among patients with the above conditions.

Kidney Transplant Outcomes of Patients With Multiple Myeloma

Introduction

Data on kidney transplantation (KTx) outcomes of patients with multiple myeloma (MM) are very limited.

Methods

We investigated the outcomes of patients with MM who underwent KTx between 1994 and 2019.

Results

A total of 12 transplants from 11 patients were included. At the time of KTx, 6 were classified as having stringent complete response (CR), 2 as CR, 2 as very good partial response (VGPR), and 2 as partial response (PR). With a median follow-up of 40 (minimum–maximum, 5–92) months after KTx, hematologic progression occurred in 9 transplants (75%). There were 3 grafts (25%) that failed, and 5 patients (45.5%) experienced death with functioning allografts. Graft survival at 1 and 5 years was 82.5% and 66%, respectively. Progression-free survival (PFS) rates of the cohort at 1, 3, and 5 years were 83.3%, 55.6%, and 44.4%, respectively. The estimated median PFS of patients who received bortezomib at any time (pre-KTx and/or post-KTx) was not reached, whereas it was 24 months for those who never received bortezomib (P = 0.281). Overall survival (OS) rates of the cohort at 1, 3, and 5 years were 81.8%, 61.4%, and 61.4%, respectively. OS of patients who received bortezomib at any time was 87.5%, 72.9%, and 72.9%, and that for those who never received bortezomib was 66.7%, 33.3%, and 33.3% (P = 0.136). All deaths occurred owing to hematologic progression or treatment-related complications.

Conclusion

Kidney transplant outcomes of patients with myeloma who received bortezomib before or after KTx seem to be more favorable. Nevertheless, relapse after KTx in MM is still common. More studies are needed to better determine who benefits from a KTx.