Circulating Tumor DNA in Patients with Renal Cell Carcinoma. A Systematic Review of the Literature

Future Directions for Circulating Tumor DNA Studies in Renal Cell Carcinoma

Circulating tumor DNA (ctDNA) is a minimally invasive biomarker that has attracted significant attention for its prognostic and predictive roles in oncology. In renal cell carcinoma (RCC), ctDNA profiling has revealed shorter ctDNA fragments and greater variability in ctDNA levels that are influenced by disease biology, tumor burden, timing, and tumor growth. Advanced detection methods, such as tumor-guided plasma analysis and methylation profiling, have enhanced sensitivity but require standardization. Emerging evidence highlights the prognostic potential of ctDNA, which correlates with worse outcomes in persistent or preoperative ctDNA positivity, advanced stage, and tumor burden. ctDNA dynamics align with therapeutic responses, and ctDNA profiling can reveal genomic alterations associated with resistance (eg, TP53, TERT) and responsiveness (eg, NF1, PIK3CA), and rare actionable mutations (eg, HER2, EGFR, BRCA1, ALK fusions). Despite limitations such as discordance in isolated intracranial progression, ctDNA complements tissue-based next-generation sequencing and facilitates real-time tumor monitoring and tracking of clonal evolution, and can guide personalized treatment strategies to improve patient outcomes. PATIENT SUMMARY: A blood test called circulating tumor DNA (ctDNA) can help doctors in monitoring cancer progression and predicting how well treatments might work. In kidney cancer, this test can detect tumor changes, guide personalized treatments, and predict outcomes earlier than traditional scans.

Advances in Adjuvant Therapy for Renal Cell Carcinoma: Perspectives on Risk Stratification and Treatment Outcomes

Radical surgery is effective for localized renal cell carcinoma (RCC). However, recurrence occurs in up to 40% of patients, underscoring the need for adjuvant therapy to improve the prognosis. Historically, adjuvant treatments, including tyrosine kinase inhibitors, have shown limited success, failing to improve overall survival. The introduction of the immune checkpoint inhibitor pembrolizumab, as demonstrated in the KEYNOTE-564 trial, has revolutionized the field by showing significant overall survival benefits and prompting updates to RCC treatment guidelines. Accurate risk assessment is critical for identifying high-risk patients most likely to benefit from adjuvant therapy. Established risk models, such as the UCLA Integrated Staging System and the Leibovich score, incorporate clinical and pathological factors to stratify recurrence risk. Recent enhancements in these models have improved predictive accuracy, enabling better optimization of inclusion criteria for clinical trials targeting high-risk recurrence and the development of individualized surveillance protocols to refine patient selection for adjuvant treatment. This review examines the evolution of risk stratification models and adjuvant therapy for RCC, highlighting the potential of innovative biomarkers, such as liquid biopsies, to further enhance patient selection and optimize treatment outcomes. Ongoing clinical trials investigating new combinations of immune checkpoint inhibitors hold promise, and integrating accurate risk assessment with advanced immunotherapy will be key to improving postoperative survival rates for patients with RCC.

Persisting challenges in the development of predictive biomarkers for immuno-oncology therapies for renal cell carcinoma

INTRODUCTION

Immuno-oncology (IO) therapies have become integral to renal cell carcinoma (RCC) management, RCC remains a complex malignancy with diverse clinical behaviors and a heterogeneous tumor microenvironment, highlighting the need for predictive biomarkers to optimize therapy.

AREAS COVERED

This review synthesizes recent findings from clinical trials, translational studies, and molecular analyses to provide an updated perspective on biomarker research for IO therapies in RCC. A literature search was conducted using PubMed, Embase, and Web of Science for articles published between January 2010 and November 2024.

EXPERT OPINION

IO combination therapies have demonstrated significant improvements in progressionfree survival and overall survival compared with sunitinib. However, treatment outcomes vary according to the IMDC risk groups, metastatic sites, and histological subtypes, such as sarcomatoid differentiation. Advances in molecular biology have elucidated the roles of genetic alterations and immune phenotypes in modulating IO efficacy. Emerging biomarkers, including tertiary lymphoid structures, human endogenous retroviruses, and the gut microbiome, show promise but require further validation. Addressing challenges such as intratumoral heterogeneity and dynamic immune responses will be key to identifying actionable biomarkers. Continued integration of clinical and molecular insights is essential for improving patient selection and outcomes in RCC treated with IO therapies.

Longitudinal Testing of Circulating Tumor DNA in Patients With Metastatic Renal Cell Carcinoma

PURPOSE

Tumor-informed circulating tumor DNA (ctDNA) has shown promise as a biomarker for treatment response monitoring (TRM) in a variety of tumor types, with the potential to improve clinical outcomes. We evaluated ctDNA status and dynamics during surveillance and as part of TRM with clinical outcomes in both patients with clear cell renal cell carcinoma (ccRCC) and non-clear cell renal cell carcinoma (nccRCC) treated with standard-of-care immunotherapy or targeted therapy regimens.

METHODS

This was a multicenter retrospective analysis of real-world data obtained from commercial ctDNA testing (Signatera, Natera, Inc) in patients with metastatic RCC. Clinical data were collected on International Metastatic RCC Database Consortium (IMDC) risk category, pathologic subtype, and grade.

RESULTS

The cohort comprised 92 patients (490 plasma samples) including both clear cell and non-clear cell histological subtypes (ccRCC: 79.3%; nccRCC: 14.1%; unclassified: 6.5%). Most of the patients belonged to the IMDC intermediate-risk category (75%, 69/92). Median follow-up was 10 months (range, 4.2-25.8). ctDNA dynamics were assessed in 56 patients on treatment, and ctDNA status was analyzed in the surveillance cohort (n = 32 patients). Serial ctDNA negativity or clearance correlated with improved progression-free survival (PFS) compared with those who became or were persistently ctDNA positive on therapy (hazard ratio [HR], 3.2; P = .012). In the surveillance cohort, patients with positive ctDNA longitudinally experienced significantly inferior PFS (HR, 18; P = .00026) compared with those who were serially negative.

CONCLUSION

Collectively, we show that serial ctDNA monitoring provides prognostic information for patients undergoing treatment or surveillance, and our findings demonstrate high concordance between ctDNA status/dynamics and subsequent clinical outcomes.

Plasma ctDNA as a Treatment Response Biomarker in Metastatic Cancers: Evaluation by the RECIST Working Group

Early indicators of metastatic cancer response to therapy are important for evaluating new drugs and stopping ineffective treatment. The RECIST guidelines based on repeat cancer imaging are widely adopted in clinical trials, are used to identify active regimens that may change practice, and contribute to regulatory approvals. However, these criteria do not provide insight before 6 to 12 weeks of treatment and typically require that patients have measurable disease. Recent data suggest that measuring on-treatment changes in the amount or proportion of ctDNA in peripheral blood plasma may accurately identify responding and nonresponding cancers at earlier time points. Over the past year, the RECIST working group has evaluated current evidence for plasma ctDNA kinetics as a treatment response biomarker in metastatic cancers and early endpoint in clinical trials to identify areas of focus for future research and validation. Here, we outline the requirement for large standardized trial datasets, greater scrutiny of optimal ctDNA collection time points and assay thresholds, and consideration of regulatory body guidelines and patient opinions. In particular, clinically meaningful changes in plasma ctDNA abundance are likely to differ by cancer type and therapy class and must be assessed before ctDNA can be considered a potential pan-cancer response evaluation biomarker. Despite the need for additional data, minimally invasive on-treatment ctDNA measurements hold promise to build upon existing response assessments such as RECIST and offer opportunities for developing novel early endpoints for modern clinical trials.

Circulating tumor DNA methylation detection as biomarker and its application in tumor liquid biopsy: advances and challenges

Circulating tumor DNA (ctDNA) methylation, an innovative liquid biopsy biomarker, has emerged as a promising tool in early cancer diagnosis, monitoring, and prognosis prediction. As a noninvasive approach, liquid biopsy overcomes the limitations of traditional tissue biopsy. Among various biomarkers, ctDNA methylation has garnered significant attention due to its high specificity and early detection capability across diverse cancer types. Despite its immense potential, the clinical application of ctDNA methylation faces substantial challenges pertaining to sensitivity, specificity, and standardization. In this review, we begin by introducing the basic biology and common detection techniques of ctDNA methylation. We then explore recent advancements and the challenges faced in the clinical application of ctDNA methylation in liquid biopsies. This includes progress in early screening and diagnosis, identification of clinical molecular subtypes, monitoring of recurrence and minimal residual disease (MRD), prediction of treatment response and prognosis, assessment of tumor burden, and determination of tissue origin. Finally, we discuss the future perspectives and challenges of ctDNA methylation detection in clinical applications. This comprehensive overview underscores the vital role of ctDNA methylation in enhancing cancer diagnostic accuracy, personalizing treatments, and effectively monitoring disease progression, providing valuable insights for future research and clinical practice.

Association of circulating tumor DNA with patient prognosis in surgically resected renal cell carcinoma

BACKGROUND

Despite complete resection, 20%-50% of patients with localized renal cell carcinoma (RCC) experience recurrence within 5 years. Accurate assessment of prognosis in high-risk patients would aid in improving outcomes. Here we evaluate the use of circulating tumor DNA (ctDNA) in RCC using banked samples and clinical data from a single institution.

METHODS

The cohort consisted of 45 RCC patients (≥pT1b) who underwent complete resection. The presence of ctDNA in plasma was determined using a personalized, tumor-informed ctDNA assay (Signatera RUO, Natera, Inc.). Relationships with outcomes and other relevant clinical variables were assessed. The median follow-up was 62 months.

RESULTS

Plasma ctDNA was detected in 18 out of 36 patients (50%) pre-operatively and was associated with increased tumor size (mean 9.3 cm vs. 7.0 cm, P < .05) and high Fuhrman grade (60% grades III-IV vs 27% grade II, P = .07). The presence of ctDNA, either pre-operatively or at any time post-operatively, was associated with inferior relapse-free survival (HR = 2.70, P = .046; HR = 3.23, P = .003, respectively). Among patients who were ctDNA positive at any time point, the sensitivity of relapse prediction was 84% with a PPV of 90%. Of note, ctDNA positivity at a post-surgical time point revealed a PPV of 100% and NPV of 64%. The lack of ctDNA detection at both time points yielded an NPV of 80%.

CONCLUSIONS

Detection of plasma ctDNA using a personalized assay is prognostic of recurrence in patients with resected RCC. Herein, we describe a successful approach for its application and identify potential limitations to be addressed in future studies.

Blood-based circulating biomarkers for prediction of immune-checkpoint inhibitors efficacy in renal cell carcinoma

Immune checkpoint inhibitors (ICI)-based combinations have become the standard first-line treatment for advanced clear cell renal cell carcinoma (ccRCC). Despite significant improvements in survival and the achievement of sustained long-term responses, a subset of patients remains refractory to ICI, and most will eventually develop resistance. Thus, identifying predictive biomarkers for ICI efficacy and resistance is essential for optimizing therapeutic strategies. Up to now, tissue-based biomarkers have not been successful as predictive biomarkers in RCC. Circulating blood-based biomarkers offer a promising alternative. These biomarkers, including circulating immune cells, soluble factors, tumor-derived markers, and those based on metabolomics, are less invasive, offer reproducibility over time, and provide a comprehensive assessment of tumor biology and patient immune status, as well as allow dynamic monitoring during treatment. This review aims to evaluate the current evidence on the different candidate circulating biomarkers being investigated for their potential to predict ICI efficacy in RCC patients.

Turning the tide: pembrolizumab's triumph in adjuvant RCC therapy

In recent years, kidney cancer has shown an increased worldwide incidence of more than 400 000 novel cases annually. Although more than half of patients are diagnosed at a localised stage, this disease presents a high-risk of relapse after surgery. Thus, there is a need for adjuvant therapy post-resection to reduce cancer recurrence and prolong disease-free and overall survival. Thorough investigation of adjuvant drugs for renal cell carcinoma (RCC) has shown little promise in the last fifty years, with no recorded overall survival benefits. This was the case until pembrolizumab, an immune checkpoint inhibitor, was introduced into the adjuvant RCC space through the KEYNOTE-564 trial. The adjuvant administration of this novel anti-PD-1 drug demonstrated a significant overall survival benefit which has led to an update in the current treatment guidelines of RCC. This substantial change in the standard of care also caused an investigation of possible treatment combinations and an adoption of innovative predictive biomarkers. In this review, we will present the evolution of past adjuvant ICI trials for the treatment of RCC, the implications of pembrolizumab's overall survival benefits and a discussion of future directions concerning new RCC drug trials and liquid biopsy-based biomarkers.

Tumor Characteristics Associated With Preoperatively Detectable Tumor-Informed Circulating Tumor DNA in Patients With Renal Masses Suspicious for Renal Cell Carcinoma

PURPOSE

Understanding the specific tumor characteristics associated with detectable circulating tumor DNA (ctDNA) in patients with renal cell carcinoma (RCC) is critical for informing future studies aiming to establish the clinical utility of such testing. We characterized the pathologic and clinical features associated with preoperatively detectable ctDNA in patients with renal masses suspicious for RCC.

METHODS

Consecutive patients who underwent partial or radical nephrectomy for nonmetastatic suspected RCC (cT1b-T3) during 2022-2023 had prospectively collected tumor-informed ctDNA analyses conducted preoperatively and postoperatively. Descriptive statistics and univariate analyses were used to describe the study findings.

RESULTS

Sixty-nine patients with a median age of 62 years (IQR, 51-70) and a median follow-up time of 7 months (IQR, 3-11) had 205 ctDNA samples collected for analysis. Thirty-nine (61%) had preoperative detectable ctDNA of 64 patients. Postoperative ctDNA status was available for 47 patients, and three (6%) had detectable ctDNA. Two had inferior vena cava (IVC) involvement, and one developed metastatic disease. Subgroup analysis of solely malignant RCC (n = 65) revealed that patients with preoperative detectable ctDNA had a higher pathologic stage (P = .001), larger tumors (7 v 4.5 cm; P = .001), higher tumor complexity (P = .022), and increased rates of tumor grades 3-4 (P = .038). All patients with gross renal vein or IVC involvement (n = 9) and those with lymphovascular invasion (n = 6) on pathology had detectable preoperative ctDNA. On univariate analysis, high tumor complexity, larger tumors, and tumor grades 3-4 were found to be predictors of preoperatively detectable ctDNA status.

CONCLUSION

Preoperative ctDNA was detectable in 61% of patients with nonmetastatic RCC, and it correlated with clinically relevant features. Clinical trials should consider incorporating both preoperative and postoperative ctDNA analyses to augment prediction of disease recurrence and to refine treatment decision making.

Post-Metastasectomy Adjuvant Therapy in Patients with Renal Cell Carcinoma: A Systematic Review

BACKGROUND

Pembrolizumab is established as adjuvant therapy for patients with high-risk clear cell renal cell carcinoma (ccRCC) after resection. Patients with completely resected metastatic disease (M1 NED) seem to have greater benefit from adjuvant pembrolizumab in both disease-free survival (DFS) and overall survival (OS); yet, with other agents, adjuvant therapy has not been shown to improve survival. As newer therapies evolve, it is important to understand the efficacy of systemic agents in this patient population.

OBJECTIVE

We aimed to systematically review available trials investigating adjuvant therapy after metastasectomy in RCC.

METHODS

Following PRISMA guidelines, we performed a systematic literature search using PubMed and Embase through January 2024. For inclusion, studies were required to include completely resected patients with known metastatic RCC. Patients with only locally advanced and/or regional nodal involvement (N1) alone were excluded. Titles and abstracts were screened to identify articles for full-text, and then a descriptive review was performed.

RESULTS

A total of 149 articles were initially identified. Ultimately 9 articles published before the end of January 2024 met our inclusion criteria and were included in the analysis. Data were extracted and organized to reflect the role of adjuvant treatment - both targeted therapies as well as immunotherapy in patients who had undergone metastasectomy and rendered M1 NED. With the exception of pembrolizumab, adjuvant therapy in M1 NED was not found to be associated with improved survival.

CONCLUSIONS

Pembrolizumab appears to benefit M1 NED ccRCC patients after resection even more than other high-risk ccRCC patients. Yet, this same benefit has not been seen with other agents. Future research should focus on trying to establish which M1 NED patients benefit from adjuvant treatment.

Une nouvelle place pour les biomarqueurs circulants dans le cancer du rein en 2024 ?

A new role for biomarkers circulating in kidney cancer in 2024?

Characterization of extrachromosomal circular DNAs in plasma of patients with clear cell renal cell carcinoma

BACKGROUND AND PURPOSE

Extrachromosomal circular DNAs (eccDNAs) have been recognized for their significant involvement in numerous biological processes. Nonetheless, the existence and molecular characteristics of eccDNA in the peripheral blood of patients diagnosed with clear cell renal cell carcinoma (ccRCC) have not yet been reported. Our aim was to identify potentially marked plasma eccDNAs in ccRCC patients.

METHODS AND MATERIALS

The detection of plasma eccDNA in ccRCC patients and healthy controls was performed using the Tn5-tagmentation and next-generation sequencing (NGS) method. Comparisons were made between ccRCC patients and healthy controls regarding the distribution of length, gene annotation, pattern of junctional nucleotide motif, and expression pattern of plasma eccDNA.

RESULTS

We found 8,568 and 8,150 plasma eccDNAs in ccRCC patients and healthy controls, respectively. There were no statistical differences in the length distribution, gene annotation, and motif signature of plasma eccDNAs between the two groups. A total of 701 differentially expressed plasma eccDNAs were identified, and 25 plasma eccDNAs with potential diagnostic value for ccRCC have been successfully screened. These up-regulated plasma eccDNAs also be indicated to originate from the genomic region of the tumor-associated genes.

CONCLUSION

This work demonstrates the characterization of plasma eccDNAs in ccRCC and suggests that the up-regulated plasma eccDNAs could be considered as a promising non-invasive biomarker in ccRCC.

ctDNA predicts clinical T1a to pathological T3a upstaging after partial nephrectomy

Most patients diagnosed with clear cell renal cell carcinoma (ccRCC) are also detected with small and organ-confined tumors, and the majority of these are classified as clinical tumor stage 1a (cT1a). A considerable proportion of patients with cT1 RCC shows tumor upstaging to pathological stage 3a (pT3a), and these patients have worse oncological outcomes. The role of circulating tumor DNA (ctDNA) in RCC has been limited to monitoring treatment response and resistance. Therefore, the present study aimed to evaluate the potential of ctDNA in predicting pT3a upstaging in cT1a ccRCC. We sequenced plasma samples preoperatively collected from 48 patients who had undergone partial nephrectomy for cT1a ccRCC using data from a prospective cohort RCC. The ctDNA were profiled and compared with clinicopathological ccRCC features to predict pT3a upstaging. Associations between ctDNA, tumor complexity, and pT3a upstaging were evaluated. Tumor complexity was assessed using the anatomical classification system. Univariate analysis used chi-squared and Student's t-tests; multivariate analysis considered significant factors from univariate analyses. Of the 48 patients with cT1a ccRCC, 12 (25%) were upstaged to pT3a, with ctDNA detected in 10 (20.8%), predominantly in patients with renal sinus fat invasion (SFI; n = 8). Among the pT3a group, ctDNA was detected in 75%, contrasting with only 2.8% in patients with pT1a (1/36). Detection of ctDNA was the only significant preoperative predictor of pT3a upstaging, especially in SFI. This study is the first to suggest ctDNA as a preoperative predictor of pT3a RCC upstaging from cT1a based on preoperative radiological images.

Established and emerging biomarkers of immunotherapy in renal cell carcinoma

Immunotherapies, such as immune checkpoint inhibitors, have heralded impressive progress for patient care in renal cell carcinoma (RCC). Despite this success, some patients' disease fails to respond, and other patients experience significant side effects. Thus, development of biomarkers is needed to ensure that patients can be selected to maximize benefit from immunotherapies. Improving clinicians' ability to predict which patients will respond to immunotherapy and which are most at risk of adverse events - namely through clinical biomarkers - is indispensable for patient safety and therapeutic efficacy. Accordingly, an evolving suite of therapeutic biomarkers continues to be investigated. This review discusses biomarkers for immunotherapy in RCC, highlighting current practices and emerging innovations, aiming to contribute to improved outcomes for patients with RCC.

Multicenter randomized trial of deferred cytoreductive nephrectomy in synchronous metastatic renal cell carcinoma receiving checkpoint inhibitors: the NORDIC-SUN-Trial

BACKGROUND

Primary tumor removal by cytoreductive nephrectomy in synchronous metastatic renal cell carcinoma patients has been investigated in the context of various treatment regimens. Two randomized controlled trials investigated the role and timing of cytoreductive nephrectomy in the era of targeted therapy and demonstrated that upfront nephrectomy should no longer be performed when patients require systemic therapy. Superiority of checkpoint immunotherapy agents has led to a paradigm change from targeted therapies to immunotherapy-based first-line treatment in patients with primary metastatic disease; thus, deferred cytoreductive nephrectomy needs to be verified in the immunotherapy setting. Furthermore, a need exists for personalizing treatment choices for the individual patient to avoid unnecessary overtreatment.

METHODS/DESIGN

To explore the impact of cytoreductive nephrectomy in this patient group receiving checkpoint immunotherapy, we initiated a randomized, controlled trial comparing deferred cytoreductive nephrectomy with no surgery. The trial integrates a comprehensive translational research program with specimen sampling for biomarker analysis.

DISCUSSION

The trial aims to show that deferred cytoreductive nephrectomy improves overall survival in patients with synchronous metastatic renal cell carcinoma, and furthermore, to identify relevant biomarkers for personalized renal cancer management.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03977571 June 6, 2019.

KIDNEY-PAGER: analysis of circulating tumor DNA as a biomarker in renal cancer - an observational trial. Study protocol

BACKGROUND

Management of localized renal cell carcinoma (RCC) is challenged by inaccurate methods to assess the risk of recurrence and deferred detection of relapse and residual disease after radical or partial nephrectomy. Circulating tumor DNA (ctDNA) has been proposed as a potential biomarker in RCC.

PURPOSE

Conduction of an observational study to evaluate the validity of ctDNA as a biomarker of the risk of recurrence and subclinical residual disease to improve postoperative surveillance.

MATERIAL AND METHODS

Urine and blood will be prospectively collected before and after surgery of the primary tumor from up to 500 patients until 5 years of follow-up. ctDNA analysis will be performed using shallow whole genome sequencing and cell-free methylated DNA immunoprecipitation sequencing. ctDNA levels in plasma and urine will be correlated to oncological outcomes. Residual blood and urine as well as tissue biopsies will be biobanked for future research.

INTERPRETATION

Results will pave the way for future ctDNA-guided clinical trials aiming to improve RCC management.

Management of Renal Cell Carcinoma: Promising Biomarkers and the Challenges to Reach the Clinic

The incidence of renal cell carcinoma (RCC) is increasing worldwide, yet research within this field is lagging behind other cancers. Despite increased detection of early disease as a consequence of the widespread use of diagnostic CT scans, 25% of patients have disseminated disease at diagnosis. Similarly, around 25% progress to metastatic disease following curatively intended surgery. Surgery is the cornerstone in the treatment of RCC; however, when the disease is disseminated, immunotherapy or immunotherapy in combination with a tyrosine kinase inhibitor is the patient's best option. Immunotherapy is a potent treatment, with durable treatment responses and potential to cure the patient, but only half of the patients benefit from the administered treatment, and there are currently no methods that can identify which patients will respond to immunotherapy. Moreover, there is a need to identify the patients in greatest risk of relapsing after surgery for localized disease and direct adjuvant treatment there. Even though several molecular biomarkers have been published to date, we are still lacking routinely used biomarkers to guide optimal clinical management. The purpose of this review is to highlight some of the most promising biomarkers, discuss the efforts made within this field to date, and describe the barriers needed to be overcome to have reliable and robust predictive and prognostic biomarkers in the clinic for renal cancer.

Liquid biopsy for Renal Cell Carcinoma: A comprehensive review of techniques, applications, and future prospects

Liquid biopsy techniques have developed rapidly in recent years and demonstrated success in cancer detection, disease characterization, and ongoing disease monitoring. These components, including circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and cell-free DNA (cfDNA), offer minimally invasive diagnostic tools that provide valuable insights into the genomic landscape of tumors. Its applications have expanded to include various malignancies, including renal cell carcinoma (RCC). RCC, a heterogeneous malignancy, poses unique diagnostic and therapeutic challenges. Up to 40% of patients experience recurrence or metastasis following initial surgical resection, necessitating the need for precise diagnostic and prognostic tools. The application of liquid biopsy in RCC, particularly through CTCs and ctDNA/cfDNA, holds significant promise. This review first delves into the various methodologies of CTC and cfDNA/ctDNA detection in RCC and highlights their roles in RCC management. Next, we discuss in depth about current existing evidence for the utilization of liquid biopsy in RCC diagnosis, prognosis, treatment outcomes prediction and association with the progression of the disease. Despite advancements, RCC's biological features, including low ctDNA shedding and significant intratumoral heterogeneity, present challenges in the clinical application of liquid biopsy. The review also discusses the limitations of current techniques and emphasizes the need for standardized protocols and further validation in large, diverse cohorts. Future directions include integrating liquid biopsy with advanced imaging techniques and leveraging artificial intelligence to improve RCC diagnostics and patient management. With continued refinement, liquid biopsy could become an essential tool in personalized oncology, improving outcomes for RCC patients.

Hypermethylated SHOX2 in circulating cell-free DNA post renal cell carcinoma surgery as TNM-independent biomarker for recurrence risk

INTRODUCTION

Adjuvant immune checkpoint inhibitor trials in renal cell carcinoma (RCC) call for improved recurrence risk stratification. Due to limitations of circulating tumor DNA (ctDNA) use in RCC, the use of hypermethylated SHOX2 gene (mSHOX2) in circulating cell-free DNA is explored as a surrogate marker for identifying high-risk patients after RCC surgery.

METHODS

Liquid biopsies were collected post-surgery from 45 RCC patients (mean duration 4.3 days). Real-time polymerase chain reaction was used to analyze SHOX2 methylation in circulating cell-free DNA. Patients were categorized as mSHOX2 positive or negative by cut-off. Metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS) were assessed using Cox regression and Log-rank analyses (median follow-up time: 60 months).

RESULTS

17 patients were mSHOX2 positive, showing unfavorable OS/CSS (Log-rank P = 0.004 and 0.02) and nearly 6-fold higher recurrence risk (hazard ratio 5.89, 95% CI 1.46-23.8). Multivariable Cox analysis confirmed mSHOX2 as an independent recurrence risk factor, disregarding TNM-based stratification.

CONCLUSIONS

mSHOX2 effectively identifies high-risk RCC patients post-surgery, indicating minimal residual disease. This easy to implement biomarker has potential for guiding of adjuvant therapy decisions.

Update on Biomarkers in Renal Cell Carcinoma

Immune checkpoint inhibitors have significantly transformed the treatment paradigm for metastatic renal cell carcinoma (RCC), offering prolonged overall survival and achieving remarkable deep and durable responses. However, given the multiple ICI-containing, standard-of-care regimens approved for RCC, identifying biomarkers that predict therapeutic response and resistance is of critical importance. Although tumor-intrinsic features such as pathological characteristics, genomic alterations, and transcriptional signatures have been extensively investigated, they have yet to provide definitive, robust predictive biomarkers. Current research is exploring host factors through in-depth characterization of the immune system. Additionally, innovative technological approaches are being developed to overcome challenges presented by existing techniques, such as tumor heterogeneity. Promising avenues in biomarker discovery include the study of the microbiome, radiomics, and spatial transcriptomics.

Managing Metastatic Renal Cell Carcinoma after Progression on Immunotherapy

Treatment of metastatic renal cell carcinoma (mRCC) after first-line immune checkpoint inhibitors (ICIs) lacks standardization, with limited evidence from small trials and retrospective data. Vascular endothelial growth factor receptor (VEGFR) inhibition through tyrosine kinase inhibitors (TKIs) is the most widely adopted second-line treatment. Encouraging results have been seen with VEGFR-TKIs in the second-line after exposure to an ICI-based combination, achieving a response rate of 30%, and 75% of patients achieving disease control. Rechallenge with ICI alone seems safe but has limited clinical benefit. Promising regimens with combination therapies and novel drugs are being evaluated in phase 3 trials.

Adjuvant immunotherapy for locally advanced renal cell carcinoma

INTRODUCTION

Locally advanced renal cell carcinoma (RCC) presents a therapeutic challenge due to 20-40% relapse risk post-nephrectomy. There has been substantial interest in utilizing immunotherapy interrupting the PD-1/PD-L1 axis in the perioperative space, especially in the adjuvant setting, in order to minimize such risk.

AREAS COVERED

We conducted a PubMed search using the terms 'adjuvant' and 'RCC.' We begin by examining landmark studies in the postoperative space for locally advanced RCC, with special emphasis on immunotherapeutic biologics. Important considerations are outlined in an effort to explain the conflicting data on the benefit of adjuvant immunotherapy as well as to adequately assess the magnitude of potential benefit of the recently approved adjuvant pembrolizumab. Relevant contemporary challenges and opportunities as well as future directions of the field are also discussed.

EXPERT OPINION

Systemic immunotherapy with monoclonal antibodies targeting the PD-1/PD-L1 axis likely holds promise, either alone or potentially in combinations, in minimizing recurrence risk for locally advanced RCC. However, emphasis on post-protocol care, robust endpoint selection, and continued work and validation on predictive biomarkers are needed to confidently select those patients that may benefit the most and minimize biologic and financial toxicity.

Longitudinal Monitoring of Circulating Tumor DNA to Assess the Efficacy of Immune Checkpoint Inhibitors in Patients With Advanced Genitourinary Malignancies

PURPOSE

Circulating tumor DNA (ctDNA) detection in blood has emerged as a prognostic and predictive biomarker demonstrating improved assessment of treatment response in patients receiving immune checkpoint inhibitors (ICIs). Here, we performed a pilot study to support the role of ctDNA for longitudinal treatment response monitoring in patients with advanced genitourinary (GU) malignancies receiving ICIs.

MATERIALS AND METHODS

Patients with histologically confirmed advanced GU malignancies were prospectively enrolled. All eligible patients received ICI treatment for at least 12 weeks, followed by serial collection of blood samples every 6-8 weeks and conventional scans approximately every 12 weeks until disease progression. ctDNA analysis was performed using Signatera, a tumor-informed multiplex-polymerase chain reaction next-generation sequencing assay. Overall, the objective response rate (ORR) was reported and its association with ctDNA status was evaluated. Concordance rate between ctDNA dynamics and conventional imaging was also assessed.

RESULTS

ctDNA analysis was performed on 98 banked plasma samples from 20 patients (15 renal, four urothelial, and one prostate). The median follow-up from the time of initiation of ICI to progressive disease (PD) or data cutoff was 67.7 weeks (range, 19.6-169.6). The ORR was 70% (14/20). Eight patients ultimately developed PD. The overall concordance between ctDNA dynamics and radiographic response was observed in 83% (15/18) of patients. Among the three patients with discordant results, two developed CNS metastases and one progressed with extracranial systemic disease while ctDNA remained undetectable.

CONCLUSION

In this pilot study, longitudinal ctDNA analysis for monitoring response to ICI in patients with advanced GU tumors was feasible. Larger prospective studies are warranted to validate the utility of ctDNA as an ICI response monitoring tool in patients with advanced GU malignancies.

Exploring the Characteristics of Circulating Tumor DNA in Pt1a Clear Cell Renal Cell Carcinoma: A Pilot Study

Circulating tumor DNA (ctDNA) is a promising biomarker for clear cell renal cell carcinoma (ccRCC); however, its characteristics in small renal masses of ccRCC remain unclear. In this pilot study, we explored the characteristics of ctDNA in pT1a ccRCC. Plasma samples were collected preoperatively from 53 patients with pT1a ccRCC. The ctDNA of pT1a ccRCC was profiled using next-generation sequencing and compared with that of higher-stage ccRCC. The association of ctDNA in pT1a ccRCC with clinicopathological features was investigated. The positive relationship of mutations between ctDNA and matched tissues was evaluated. In pT1a ccRCC, the ctDNA detection rate, cell-free DNA concentration, and median variant allele frequency were 20.8%, 5.8 ng/mL, and 0.38%, respectively, which were significantly lower than those in metastatic ccRCC. The ctDNA gene proportions in pT1a samples differed from those in metastatic ccRCC samples. The relationships between ctDNA and tumor size, tumor grade, and patient age were not elucidated. The positive concordance between ctDNA and matched tissues was poor for pT1a ccRCC. Strategies are needed to increase sensitivity while eliminating noise caused by clonal hematopoiesis to increase the clinical utility of ctDNA analysis in small renal masses of ccRCC.

Revisiting mechanisms of resistance to immunotherapies in metastatic clear-cell renal-cell carcinoma

Renal-cell carcinoma (RCC) remains a leading cause of cancer-related mortality worldwide. Though newer therapeutic combinations of immune checkpoint inhibitors and targeted therapies have greatly improved outcomes, resistance to these therapies is becoming a challenge for long-term control. Mechanisms of resistance have been explored in a variety of solid tumors, including RCC. Based upon our review of the current literature on the mechanisms of resistance to immunotherapies for the management of metastatic clear-cell renal cell carcinomas (mccRCC), the ensuing conclusions have been made: The management of mccRCC has progressed substantially with the advent of checkpoint inhibitors and targeted oral therapies, alone and/or in combination. Nevertheless, innate or developed resistance to these therapies remains an ongoing challenge, particularly to immune checkpoint inhibitors (ICIs). Several of the known mechanisms of resistance have been well defined, but recent progression in cellular therapies helps to expand the armamentarium of potential combination options that may overcome these modes of resistance and improve long-term disease control and survival for an otherwise dismal disease. In the ensuing review and update of the literature on the mechanisms of resistance to immunotherapies in mccRCC, we have revisited the known resistance mechanisms of immunotherapies in metastatic clear-cell RCC and explored ongoing and future strategies to overcome them.

The Promise of Neoadjuvant and Adjuvant Therapies for Renal Cancer

Because metachronous metastatic disease will develop in 20% to 40% of patients with presumed localized renal cell carcinoma (RCC) treated surgically, research is focused on neoadjuvant and adjuvant systemic therapy, to improve disease-free and overall survival. Neoadjuvant therapies trialed include anti-vascular endothelial growth factor (VEGF) tyrosine kinase inhibitor (TKI) agents, or combination therapies (immunotherapy with TKI), and aim to improve resectability of locoregional RCC. Adjuvant therapies trialed include cytokines, anti-VEGF TKI agents, or immunotherapy. These therapeutics can facilitate the surgical extirpation of the primary kidney tumor in the neoadjuvant setting and improve disease-free survival in the adjuvant setting.

Circulating Tumor Cells as Biomarkers for Renal Cell Carcinoma: Ready for Prime Time?

Renal cell carcinoma (RCC) is among the 15 most common cancers worldwide, with rising incidence. In most cases, this is a silent disease until it reaches advance stages, demanding new effective biomarkers in all domains, from detection to post-therapy monitoring. Circulating tumor cells (CTC) have the potential to provide minimally invasive information to guide assessment of the disease's aggressiveness and therapeutic strategy, representing a special pool of neoplastic cells which bear metastatic potential. In some tumor models, CTCs' enumeration has been associated with prognosis, but there is a largely unexplored potential for clinical applicability encompassing screening, diagnosis, early detection of metastases, prognosis, response to therapy and monitoring. Nonetheless, lack of standardization and high cost hinder the translation into clinical practice. Thus, new methods for collection and analysis (genomic, proteomic, transcriptomic, epigenomic and metabolomic) are needed to ascertain the role of CTC as a RCC biomarker. Herein, we provide a critical overview of the most recently published data on the role and clinical potential of CTCs in RCC, addressing their biology and the molecular characterization of this remarkable set of tumor cells. Furthermore, we highlight the existing and emerging techniques for CTC enrichment and detection, exploring clinical applications in RCC. Notwithstanding the notable progress in recent years, the use of CTCs in a routine clinical scenario of RCC patients requires further research and technological development, enabling multimodal analysis to take advantage of the wealth of information they provide.

The Continuing Question of Adjuvant Therapy in Clear Cell Renal Cell Carcinoma

Treatment advances in kidney cancer continually evolve. The focus of treatment options continues with oral vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) or intravenous immune checkpoint inhibitors (ICIs). Multiple trials exploring the role of adjuvant treatment after cytoreductive nephrectomy in high-risk clear cell renal cell carcinoma are currently ongoing. The discovery of biomarkers may help determine which patients benefit from these treatments, but these are not yet available outside clinical studies. Trials with combination therapies are also ongoing, especially using novel therapies with new mechanisms of action, and will hopefully provide more clues on proper patient and therapy selection in the adjuvant setting.