Understanding the Importance of Smart Drugs in Renal Cell Carcinoma

First-Line Treatments and Management of Metastatic Renal Cell Carcinoma Patients: An Italian Interdisciplinary Uro-Oncologic Group Algorithm

The treatment landscape for metastatic renal cell carcinoma (mRCC) has undergone significant transformations in recent years. The introduction of novel combination therapies involving tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors has resulted in improved oncological outcomes compared to traditional TKI monotherapy. In this evolving paradigm, the pivotal role of the multidisciplinary tumor board is underscored, particularly in shaping the therapeutic trajectory for patients eligible for locoregional interventions like cytoreductive nephrectomy and metastasectomy. In cases where systemic treatment is deemed appropriate, the absence of direct comparisons among the various combination therapies complicates the selection of a first-line approach. The clinician is faced with the challenge of making decisions based on patient-specific factors such as performance status, risk classification according to the International Metastatic Renal Cell Carcinoma Database Consortium, comorbidities, and disease characteristics, including the number and location of metastases and tumor histology. Considering these concerns, we propose, as a member of a Tuscany Interdisciplinary Uro-Oncologic Group, an algorithm to streamline the decision-making process for mRCC patients, offering guidance to clinicians in their day-to-day clinical practice.

Impact of BMI on the Survival of Renal Cell Carcinoma Patients Treated with Targeted Therapy: A Systematic Review and Meta-Analysis

It is unclear whether obese renal cell carcinoma (RCC) patients treated with targeted therapy have better survival. We conducted this meta-analysis to assess the prognostic significance of body mass index (BMI) in RCC patients treated with targeted therapy. We systematically searched PubMed, Embase, Cochrane Library, and Web of Science by November 17, 2021. We calculated effect outcomes using random-effects and fixed-effects models. Fifteen articles were identified. We found that RCC patients treated with targeted therapy with BMI over 25 obtained better overall survival (OS) (hazard ratio [HR] = 0.69, 95% confidence interval [CI] = 0.58-0.82, I2 = 75.5%, p < 0.001) and progression-free survival (PFS) (HR = 0.71, 95%CI = 0.55-0.92, I2 = 69.7%, p = 0.006) than patients with BMI below 25. Obese (BMI over 30) patients had remarkably better OS (HR = 0.77, 95%CI = 0.70-0.85, I2 = 0.0%, p = 0.439) and PFS (HR = 0.86, 95%CI = 0.77-0.97, I2 = 0.0%, p = 0.934) than patients with BMI below 25. Overweight (BMI over 25 but below 30) patients also had better OS (HR = 0.86, 95%CI = 0.79-0.93, I2 = 17.7%, p = 0.295) and PFS (HR = 0.82, 95%CI = 0.74-0.90, I2 = 0.0%, p = 0.904) than patients with BMI below 25. When using BMI as continuous variable, patients with high BMI also obtained significantly better OS (HR = 0.92, 95%CI = 0.88-0.96, I2 = 0.0%, p = 0.806). Therefore, higher BMI was associated with greater OS and PFS in RCC patients treated with targeted therapy.

Management of metastatic renal cell carcinoma following prior vascular endothelial growth factor-targeted therapy: A real-world retrospective study from Taiwan

BACKGROUND

There are limited real-world data to guide the sequencing of targeted therapies in patients with metastatic renal cell carcinoma (mRCC). The objective of this study was to characterize real-world treatment patterns (primarily second line [2L]) after prior vascular endothelial growth factor (VEGF) targeted therapy in an unselected mRCC population from Taiwan between 2013 and 2017. Treatment-related adverse events (TRAEs) and their management were also evaluated (NCT03633579).

METHODS

This retrospective cohort study included patients who had received prior VEGF-targeted therapy and were treated at the National Taiwan University Hospital or the Taipei Veterans General Hospital between June 2013 and December 2017. Outcomes were characterized using descriptive statistics.

RESULTS

Overall, 27 patients were included: 22 (81.5%) male; mean standard deviation (SD) age, 63.1 (11.1) years; 18 (66.7%) initiated targeted therapy during the year immediately following mRCC diagnosis. All patients received sunitinib as their first-line (1L) targeted therapy, with a median (range) treatment duration of 10 (1.8-65.8) months. The most common reason for discontinuing 1L sunitinib was disease progression (88.9% of patients). Everolimus was the most common 2L targeted therapy, in 23 patients (85.2%); 4 patients (14.8%) received 2L axitinib. Median (range) duration of 2L therapy was 4.0 (0.1-30.5) months for everolimus and 4.2 (0.5-9.2) months for axitinib. Ten TRAEs were reported among seven patients receiving 2L everolimus: hypertension (n = 5), hand-foot syndrome (n = 2), hyperglycemia (n = 1), renal failure (n = 1), and interstitial pneumonitis (n = 1). The majority (80%) of TRAEs were managed in the outpatient setting. No TRAEs were reported in the axitinib group.

CONCLUSION

Real-world management of patients with mRCC in Taiwan broadly aligned with clinical guidelines and national reimbursement policy at the time of the study. These findings may be a useful reference for assessing the implications of evolving mRCC management approaches in Taiwan.

What is the optimum systemic treatment for advanced/metastatic renal cell carcinoma of favourable, intermediate and poor risk, respectively? A systematic review and network meta-analysis

PURPOSE

The optimum systemic therapies for advanced/metastatic renal cell carcinoma (RCC) of favourable, intermediate and poor risk have not been established. We aimed to compare and rank the effects associated with systemic therapies in the first-line setting.

METHODS

We searched PubMed, Cochrane databases, Web of Science and ClinicalTrials.gov for randomised controlled trials (RCT) published up to February 2020 of all available treatments for advanced/metastatic RCC. Analysis was done on a Bayesian framework.

RESULTS

15 unique RCTs including 8995 patients were identified. For advanced/metastatic RCC of favourable risk, avelumab plus axitinib was associated with a significantly higher improvement in progression-free survival (PFS) than sunitinib (HR 0.57, 95% CI 0.34 to 0.96). For intermediate-risk patients, cabozantinib, nivolumab plus ipilimumab, pembrolizumab plus axitinib and avelumab plus axitinib were associated with significantly higher improvement in PFS than sunitinib (HR 0.63, 95% CI 0.44 to 0.97; HR 0.66, 95% CI 0.53 to 0.81; HR 0.58, 95% CI 0.44 to 0.80; HR 0.62, 95% CI 0.47 to 0.83, respectively); pembrolizumab plus axitinib and nivolumab plus ipilimumab were associated with significantly higher improvement in overall survival (OS) than sunitinib (HR 0.53, 95% CI 0.34 to 0.81; HR 0.66, 95% CI 0.50 to 0.87, respectively). For poor-risk patients, nivolumab plus ipilimumab and pembrolizumab plus axitinib were associated with significantly higher improvement in PFS than sunitinib (HR 0.57, 95% CI 0.43 to 0.76; HR 0.48, 95% CI 0.30 to 0.82, respectively); nivolumab plus ipilimumab and pembrolizumab plus axitinib were significantly more efficacious for OS than sunitinib (HR 0.57, 95% CI 0.39 to 0.883; HR 0.43, 95% CI 0.23 to 0.80, respectively). For OS, there were 81% and 78% probabilities that pembrolizumab plus axitinib was the best option for intermediate-risk and poor-risk patients, respectively.

CONCLUSION

Avelumab plus axitinib might be the optimum treatment for advanced/metastatic RCC of favourable risk. Pembrolizumab plus axitinib might be the optimum treatment for intermediate-risk and poor-risk patients.

[Pulmonary metastasectomy in renal cell carcinoma]

BACKGROUND

In patients with isolated meta- or synchronous pulmonary metastases from renal cell cancer, lung metastasectomy could be an appropriate treatment option after successful treatment of primary cancer.

OBJECTIVES

Presentation of lung metastasectomy as a treatment option in patients with pulmonary metastatic renal cell cancer and the postoperative outcome. Description of alternative treatment modalities focusing on "targeted therapies".

MATERIALS AND METHODS

Systematical literature research and qualitative analysis of studies on patients undergoing lung metastasectomy after primary nephrectomy published since 01 January 2000. We assessed operative findings, survival data, and prognostic factors.

RESULTS

Pulmonary metastasectomy results in a median postmetastasectomy survival of 26-94 months. The 5‑year survival rates vary between 33 and 58%. The patients' prognosis depends on a prolonged disease-free interval and complete resection of all suspected metastases. In particular, number and location of lung metastases should play a minor role for the indication for lung metastasectomy.

CONCLUSIONS

Pulmonary metastasectomy should be considered the treatment of choice in selected patients with successfully resected primary cancer showing no evidence of extrapulmonary metastases and having guaranteed operability and complete resection.

A three-molecule score based on Notch pathway predicts poor prognosis in non-metastasis clear cell renal cell carcinoma

We constructed a three-molecule score based on the expression of Notch pathway molecules: Jagged1, intracellular Notch1 (ICN1) and Hes1 (JIH score). To assess prognostic value of the JIH score in non-metastasis clear cell renal cell carcinoma (ccRCC), we identified 467 patients who underwent nephrectomy during 2008-2009 as our study population. Immunohistochemistry was used to evaluate the expression of these three molecules. Cox regression models were applied to construct the JIH score, while Kaplan-Meier methods, multivariate analyses and nomogram were used to explore prognostic value of the JIH score. Our result confirmed that JIH score was an independent prognosticator for both overall survival (OS) and recurrence-free survival (RFS). Survival analyses showed that a higher JIH score indicated worse clinical outcomes (JIH score 3: 58.3% and 58.0% for 6-year OS and RFS, respectively; JIH score 0: 96.7% and 91.6% for 6-year OS and RFS, respectively). Nomograms based on JIH score and other conventional clinicopathological features had a better capability in predicting patients with pT1 stage disease for both OS and RFS (84.6% and 83.9%, respectively). The JIH score is a novel prognosticator representing activation of Notch pathway for non-metastasis ccRCC, and raises an alternative strategy for excavating potential biomarkers for signal pathways.

Skeletal metastasis in renal cell carcinoma: A review

Background

Renal cell carcinoma account for 3% of all cancers, with peak incidence between 60 and 70 years of age predominantly affecting male population. Renal carcinoma is the most common malignancy of kidney constitutes for 80–90% of renal neoplasm with an overall 45% five years survival rate. Majority are diagnosed incidentally during investigation for other disease process of abdomen. Classical triad of gross hematuria, pain and palpable mass in abdomen is rare accounting to only 6–10%. Treatment of early stages of disease i.e. localized disease is partial or radical nephrectomy. Most common metastasis in RCC occurs to lung, followed by bone involvement in 20–35%, lymph nodes, liver, adrenal gland and brain. In metastatic disease median survival rate of patient is about eight months with 50% mortality rate within first year of life, five years survival rate is 10%. Skeletal metastasis are very destructive in patients with renal cell carcinoma compromising bone integrity leading to skeletal related events including pains, impending fractures, nerve compressions, hypercalcemia and even pathological fractures which may require surgical interventions and other therapy. In addition to skeletal complications, presence of bone metastases in RCC has negative impact on progression free survival and overall survival of patients treated with systemic therapies.

Objective

In this review we discuss pathophysiology of tumor metastasis, diagnosis, management and Case examples of metastatic renal cell carcinoma.

Conclusion

Incidence of metastatic renal carcinoma is increasing. Overall prognosis of patient with advanced RCC is poor, emphasizing the importance of early detection and prompt treatment of primary lesion in its early stage. Advancement in targeted therapy in recent decades had made some improvement in treatment of SREs and has helped in improving patent's quality of life but still we are in need of further improvement in treatment modalities to cure disease thereby decreasing morbidity and mortality.

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Renal cell carcinoma account for 3% of all cancers.

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It is a very destructive that may compromise bone integrity.

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Most common metastasis in renal cell carcinoma occurs to lung, followed by bone , lymph nodes, liver, adrenal gland and brain.

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Most common metastasis in renal cell carcinoma occurs to lung, followed by bone involvement in 20–35%, lymph nodes, liver, adrenal gland and brain.

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In metastatic disease median survival rate of patient is about eight months with 50% mortality rate within first year of life, five years survival rate is 10.

Rho GDP dissociation inhibitor-β in renal cell carcinoma

Rho GDP dissociation inhibitor-β (ARHGDIB) is an important mediator of cell signaling. The expression of ARHGDIB is associated with tumor growth and metastasis in a variety of non-genitourinary cancers; however, the role of ARHGDIB in renal cell carcinoma (RCC) has not yet been evaluated. In the present study, tissue samples from 105 patients undergoing surgery for RCC were obtained. The expression levels of ARHGDIB mRNA in normal kidney tissues and in corresponding cancer tissues were analyzed by reverse transcription-quantitative polymerase chain reaction. Differences in relative mRNA expression levels were assessed using paired two-sample t-tests. Expression levels were analyzed with respect to various clinical parameters, and associations were tested using a bivariate logistic regression model. Relative mRNA expression levels in healthy renal tissues compared with cancerous tissues from the same kidney were assessed using paired t-tests. Expression data were compared with respect to survival data by the Kaplan-Meier method/Cox regression analysis. The results revealed that the relative mRNA expression level of ARHGDIB was significantly higher in the lysates of RCC tumor tissues (P<0.001) when compared with healthy renal tissues in a paired analysis of 74 samples; this finding was consistent with the analysis of ARHGDIB mRNA expression levels in all RCC samples, as well as in the subset of clear cell RCC (ccRCC) samples. The relative mRNA expression level of ARHGDIB was also increased in ccRCC tissues compared with papillary RCC tissues (P<0.001). On univariate Cox regression analysis, recurrence-free survival (RFS) was significantly associated with metastasis, locally advanced disease and tumor grade (P=0.018, P=0.002 and P<0.001, respectively). Furthermore, in the subgroup of patients with ccRCC, increased ARHGDIB mRNA expression was significantly associated with a longer RFS time (P=0.001). In summary, the results indicate that ARHGDIB mRNA is highly expressed in RCC tissues in general and is positively associated with RFS in ccRCC. As ARHGDIB has a known effect on angiogenesis and immune modulation, the present study suggests that the functional analysis of ARHGDIB should be performed in the future.

Intermittent hypoxia increases kidney tumor vascularization in a murine model of sleep apnea

We investigate the effects of intermittent hypoxia (IH), a characteristic feature of obstructive sleep apnea (OSA), on renal cancer progression in an animal and cell model. An in vivo mouse model (Balb/c, n = 50) of kidney cancer was used to assess the effect of IH on tumor growth, metastatic capacity, angiogenesis and tumor immune response. An in vitro model tested the effect of IH on RENCA cells, macrophages and endothelial cells. Tumor growth, metastatic capacity, circulating vascular endothelial growth factor (VEGF) and content of endothelial cells, tumor associated macrophages and their phenotype were assessed in the tumor. In vitro, VEGF cell expression was quantified.Although IH did not boost tumor growth, it significantly increased endothelial cells (p = 0.001) and circulating VEGF (p<0.001) in the in vivo model. Macrophages exposed to IH in vitro increased VEGF expression, whereas RENCA cells and endothelial cells did not. These findings are in keeping with previous clinical data suggesting that OSA has no effect on kidney cancer size and that the association observed between OSA and higher Fuhrman grade of renal cell carcinoma may be mediated though a proangiogenic process, with a key role of macrophages.

Systemic therapy in metastatic renal cell carcinoma

PURPOSE

Current systemic treatment of targeted therapies, namely the vascular endothelial growth factor-antibody (VEGF-AB), VEGF receptor tyrosine kinase inhibitor (TKI) and mammalian target of rapamycin (mTOR) inhibitors, have improved progression-free survival and replaced non-specific immunotherapy with cytokines in metastatic renal cell carcinoma (mRCC).

METHODS

A panel of experts convened to review currently available phase 3 data for mRCC treatment of approved agents, in addition to available EAU guideline data for a collaborative review as the plurality of substances offers different options of first-, second- and third-line treatment with potential sequencing.

RESULTS

Sunitinib and pazopanib are approved treatments in first-line therapy for patients with favorable- or intermediate-risk clear cell RCC (ccRCC). Temsirolimus has proven benefit over interferon-alfa (IFN-α) in patients with non-clear cell RCC (non-ccRCC). In the second-line treatment TKIs or mTOR inhibitors are treatment choices. Therapy options after TKI failure consist of everolimus and axitinib. Available third-line options consist of everolimus and sorafenib. Recently, nivolumab, a programmed death-1 (PD1) checkpoint inhibitor, improved overall survival benefit compared to everolimus after failure of one or two VEGFR-targeted therapies, which is likely to become the first established checkpoint inhibitor in mRCC. Data for the sequencing of agents remain limited.

CONCLUSIONS

Despite the high level of evidence for first and second-line treatment in mRCC, data for third-line therapy are limited. Possible sequences include TKI-mTOR-TKI or TKI-TKI-mTOR with the upcoming checkpoint inhibitors in perspective, which might settle a new standard of care after previous TKI therapy.

Structural characterization of mammalian bHLH-PAS transcription factors

The mammalian basic helix-loop-helix-PER-ARNT-SIM (bHLH-PAS) transcription factors share common architectural features that include a bHLH DNA-binding domain and tandemly positioned PAS domains. The sixteen members of this family include the hypoxia-inducible factors (HIF-1α and HIF-2α), ARNT (also known as HIF-1β), CLOCK and BMAL1. Most bHLH-PAS proteins have been genetically linked to variety of diseases in humans, including cancers, metabolic syndromes and psychiatric conditions. To function as transcription factors, the bHLH-PAS proteins must form heterodimeric complexes. Recent crystallographic studies of HIF-α-ARNT and CLOCK-BMAL1 complexes have unveiled the organization of their multi-domain bHLH-PAS-A-PAS-B segments, revealing how these architectures can give rise to unique patterns of heterodimerization. As our structural understanding becomes better integrated with ligand-discovery and target gene identification, a more comprehensive picture of their architectural and functional properties will emerge.

Predictive Immunohistochemical Markers Related to Drug Selection for Patients Treated with Sunitinib or Sorafenib for Metastatic Renal Cell Cancer

Targeted drug decisions in metastatic renal cell carcinoma are exclusively made on the basis of clinical criteria. We investigated whether these biomarkers (HIF-1α, HIF-2α, CAIX, VEGF, VEGFR1, VEGFR2, VEGFR3, PDGFB, PDGFRA, PDGFRB, CD31, CD44, bcl-xL, KIT, p21, CXCR4, PTEN, (CSF)-1R, RET, and FLT-3) can predictive the different effects between sunitinib and sorafenib treatments and are available to guide targeted drug selection. We enrolled all patients who underwent nephrectomy with postoperative sunitinib- or sorafenib-treatment at our institution from 2007 to 2012. Immunohistochemical approach was applied to assess the potential differential effects of immunostainings between sunitinib- and sorafenib-treated groups. We found that patients with high HIF-2α, CD31 expression showed greater relative PFS and OS benefit and patients with high CAIX expression presented greater relative OS benefit from sunitinib than from sorafenib, patients with high VEGFR1 or PDGFRB expression levels exhibited worse relative PFS benefit from sunitinib than from sorafenib. Namely high HIF-2α, CD31, and CAIX expression levels along with low VEGFR1 and PDGFRB expression levels improved the benefit of sunitinib treatment compared with sorafenib treatment. These results can identify whether patients can benefit more from sunitinib or sorafenib for drug selection guidance, eventually with precision medicine.

Obstructive sleep apnea and Fuhrman grade in patients with clear cell renal cell carcinoma treated surgically

PURPOSE

To assess the association between obstructive sleep apnea (OSA) and Fuhrman grade in patients with clear cell renal cell carcinoma (ccRCC). As secondary endpoints, we studied its association with tumor size, metastasis-free survival (MFS) and cancer-specific survival (CSS).

METHODS

We reviewed the databases of two tertiary care centers, identifying 2579 patients who underwent partial or radical nephrectomy for ccRCC between 1991 and 2014. Descriptive statistics were used to compare pathologic variables between patients with and without OSA. Linear and logistic regression models were used to assess the association of OSA with Fuhrman grade and tumor size. A Cox proportional hazards model was used to determine OSA association with MFS and CSS. A pathway analysis was performed on a cohort with available gene expression data.

RESULTS

In total, 172 patients (7 %) had self-reported OSA at diagnosis. More patients with OSA had high Fuhrman grade compared to those without OSA [51 vs. 38 %; 13 % risk difference; 95 % confidence interval (CI), 5-20 %; p = 0.003]. On multivariable analysis, the association remained significant (OR 1.41; 95 % CI 1.00-1.99; p = 0.048). OSA was not associated with tumor size (p > 0.5), MFS (p = 0.5) or CSS (p = 0.4). A trend toward vascular endothelial growth factor pathway enrichment was seen in OSA patients (p = 0.08).

CONCLUSIONS

OSA is associated with high Fuhrman grade in patients undergoing surgery for ccRCC. Pending validation of this novel finding in further prospective studies, it could help shape future research to better understand etiological mechanisms associated.

EAU guidelines on renal cell carcinoma: 2014 update

CONTEXT

The European Association of Urology Guideline Panel for Renal Cell Carcinoma (RCC) has prepared evidence-based guidelines and recommendations for RCC management.

OBJECTIVES

To provide an update of the 2010 RCC guideline based on a standardised methodology that is robust, transparent, reproducible, and reliable.

EVIDENCE ACQUISITION

For the 2014 update, the panel prioritised the following topics: percutaneous biopsy of renal masses, treatment of localised RCC (including surgical and nonsurgical management), lymph node dissection, management of venous thrombus, systemic therapy, and local treatment of metastases, for which evidence synthesis was undertaken based on systematic reviews adhering to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Relevant databases (Medline, Cochrane Library, trial registries, conference proceedings) were searched (January 2000 to November 2013) including randomised controlled trials (RCTs) and retrospective or controlled studies with a comparator arm. Risk of bias (RoB) assessment and qualitative and quantitative synthesis of the evidence were performed. The remaining sections of the document were updated following a structured literature assessment.

EVIDENCE SYNTHESIS

All chapters of the RCC guideline were updated. For the various systematic reviews, the search identified a total of 10,862 articles. A total of 151 studies reporting on 78,792 patients were eligible for inclusion; where applicable, data from RCTs were included and meta-analyses were performed. For RCTs, there was low RoB across studies; however, clinical and methodological heterogeneity prevented data pooling for most studies. The majority of studies included were retrospective with matched or unmatched cohorts based on single or multi-institutional data or national registries. The exception was for systemic treatment of metastatic RCC, in which several RCTs have been performed, resulting in recommendations based on higher levels of evidence.

CONCLUSIONS

The 2014 guideline has been updated by a multidisciplinary panel using the highest methodological standards, and provides the best and most reliable contemporary evidence base for RCC management.

PATIENT SUMMARY

The European Association of Urology Guideline Panel for Renal Cell Carcinoma has thoroughly evaluated available research data on kidney cancer to establish international standards for the care of kidney cancer patients.

The current status of tailor-made medicine with molecular biomarkers for patients with clear cell renal cell carcinoma

Appropriate use of multiple reliable molecular biomarkers in the right context will play a role in tailormade medicine of clear cell renal cell carcinoma (RCC) patients in the future. A total of 11,056 patients from 53 studies were included in this review. The article numbers of the each evidence levels, using the grading system defined by the Oxford Centre for Evidence-based Medicine, in 1b, 2a, 2b, and 3b were 5 (9%), 18 (34%), 29 (55%), and 1 (2%), respectively. The main goal of using biomarkers is to refine predictions of tumor progression, pharmacotherapy responsiveness, and cancer-specific and/or overall survival. Currently, carbonic anhydrase (CA9) and vascular endothelial growth factor (VEGF) in peripheral blood and p53 in tumor tissues are measured to predict metastasis, while VEGF-related proteins in peripheral blood are used to assess pharmacotherapy responsiveness with sunitinib. Furthermore, interleukin 8, osteopontin, hepatocyte growth factor, and tissue inhibitors of metalloproteinases-1 in peripheral blood enable assessment of responsiveness to pazopanib treatment. Other reliable molecular biomarkers include von Hippel–Lindau gene alteration, hypoxia-inducible factor-1a, CA9, and survivin in tumor tissues and VEGF in peripheral blood for predicting cancer-specific survival. In the future, studies should undergo external validation for developing tailored management of clear cell RCC with molecular biomarkers, since individual institutional studies lack the generalization and consistency required to maintain accuracy among different patient series.

Underactivation of the adiponectin-adiponectin receptor 1 axis in clear cell renal cell carcinoma: implications for progression

Energy-sensing pathways, normally coordinated by 5' AMP-activated protein kinase (AMPK), are dysregulated in renal cell carcinoma (RCC). Obesity can accentuate the pre-existing pro-tumorigenic metabolic machinery in RCC cells through its associated obesogenic hormonal milieu, characterized by lower circulating levels of adiponectin. In RCC patients, low adiponectin levels associate clinically with more aggressive disease. We investigated the adiponectin signaling pathway in RCC, focusing on adiponectin receptor 1 (AdipoR1) and associated activation of AMPK. AdipoR1 protein in RCC and normal surrounding renal tissues was determined by Western blot analysis and immunohistochemistry. Anti-tumorigenic effects of adiponectin in RCC cells in vitro were investigated via VEGF and MMP ELISA and invasion assays. Using in vivo models of RCC, the effect of AdipoR1-knockdown (shRNA) on tumor latency, growth and dissemination were determined. AdipoR1 protein was significantly reduced in clear cell RCC specimens. Adiponectin treatment inhibited VEGF, MMP-2 and MMP-9 secretion and activity and invasive and migratory capacities of RCC cells. AMPKα1-knockdown (shRNA) attenuated adiponectin's effects. In cells stably expressing AdipoR1-specific shRNA, AMPK activation by adiponectin was significantly reduced compared to cells expressing control shRNA. In vivo, AdipoR1 knockdown increased the growth, dissemination and angiogenesis of RCC. These findings suggest that deficiencies in the entire adiponectin hormonal axis (the hormone and its receptor) result in underactivation of AMPK leading to increased angiogenic and invasive capacities of RCC. The established link between obesity and RCC can therefore be further explained by the adiponectin deficiency in obese individuals together with reduced AdipoR1 protein in RCC.

Sorafenib or sunitinib as postoperative adjuvant therapy for Chinese patients with locally advanced clear cell renal cell carcinoma at high risk for disease recurrence

OBJECTIVE

To evaluate the efficacy and safety of targeted agents (sorafenib and sunitinib) as postoperative adjuvant therapy in Chinese patients with clear cell renal cell carcinoma (CC-RCC) who are at high risk for disease recurrence.

MATERIALS AND METHODS

Forty-three patients treated at our center between December 2007 and December 2010 with locally advanced CC-RCC who were at a high risk for disease recurrence were enrolled into the study. The criteria for high risk of CC-RCC recurrence postoperatively were defined according to the Mayo Clinic stage, size, grade, and necrosis (SSIGN) score for CC-RCC. After radical nephrectomy, patients received either sorafenib (group A, n = 20) or sunitinib (group B, n = 23) and were followed up for at least 1 year to determine the efficacy and safety of the test products. The duration of maintenance targeted medication treatment was approximately 1 year. Group C consisted of 388 CC-RCC patients treated at our center between 1992 and 2007, who were at high risk for disease recurrence and who received no adjuvant therapy.

RESULTS

The demography characteristics were similar among the 3 groups. The overall rate of recurrence in groups A and B was not different (15.0% and 17.4% (P > 0.05), respectively), which was lower than that of group C (38.7%, P < 0.05 compared with groups A and B). Disease-free survival (DFS) was longer in groups A and B (18.9 ± 5.9 months and 16.9 ± 6.1 months [P > 0.05], respectively), compared with group C (13.3 ± 7.2 months, P < 0.05 compared with groups A and B). The common adverse effects of targeted therapy included hand-foot syndrome, fatigue, diarrhea, taste disturbance, rash, hypertension, alopecia, stomatitis, neutropenia, nausea, pruritus, hypothyroidism in groups A and B. The adverse effects were mild in both groups and the incidence was not significantly different between groups A and B.

CONCLUSIONS

Targeted adjuvant therapy postoperatively with sorafenib or sunitinib in patients with CC-RCC who are at a high risk for disease recurrence was well tolerated and effective in reducing the rate of CC-RCC recurrence in these patients. This study is an attempt to assess the utility of adjuvant tyrosine kinase inhibitors (TKIs) after surgery for renal carcinoma. The apparently improved outcomes, compared with a historical control population, are of sufficient interest to support the continuation of an ongoing randomized clinical trial to validate the hypothesis.

Kidney Cancer: Current Progress in Treatment

Kidney cancer accounts for approximately 2% of all cancers worldwide, with renal cell carcinoma being the most widespread form. Worldwide, the occurrence and mortality rates are rising by 2–3% per decade. Cigarette smoking, obesity, acquired cystic kidney disease and inherited vulnerability are identified risk issues for kidney cancer. Immunotherapy confers a small but significant overall survival benefit in metastatic renal cell carcinoma but only for the minority of patients, i.e. the 20% with good predictive characteristics. Current developments in the molecular biology of renal cell carcinoma have recognized multiple pathways related with the progress of this cancer. Several strategies have been explored targeting these trails, with major clinical benefits shown in early studies. New agents including the small molecule targeted inhibitors like sunitinib, sorafenib and temsirolimus, and the monoclonal antibody bevacizumab have shown anti-tumour activity in randomised clinical trials and have become the standard of care for most patients.

[Targeted therapy of urological tumours. Experimental field or established therapeutic approach?]

Unlike conventional systemic chemotherapies, the aim of targeted therapeutic approaches is not to address general mechanisms involved in cellular replication. In contrast, they aim at such regulatory pathways that have been identified to be involved in the progression of human malignant disease. Whereas the application of targeted therapeutic modalities is well established for the treatment of metastatic renal cell cancer, only very few data on their clinical efficacy during the treatment of other urological tumours such as prostate and bladder cancer are currently available. The aim of this paper is to reflect on the current status regarding the relevance of targeted therapeutic approaches during the treatment of urological cancers of different origin.

Immunochemotherapy-associated protein patterns in tumour tissue and serum of patients with metastatic renal cell carcinoma

CONTEXT

Systemic treatment of metastatic renal cell carcinoma (mRCC) with targeted therapies became widely accepted; however, there are few patients who greatly benefit from immunochemotherapy (ICT). It is crucial to recognize these patients for individual treatment.

OBJECTIVES

Definition of protein patterns in tissue and serum from mRCC-patients to predict benefit from ICT.

MATERIALS AND METHODS

Twenty-five tissue samples and 59 sera were analysed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). Protein peaks of interest were identified by 2D-PAGE and peptide mass fingerprinting. Validation was carried out by Western Blot and ELISA.

RESULTS

Protein patterns associated with therapy response were determined. Caveolin-1 (CAV-1) and plasminogen activator inhibitor 1 (PAI-1) were identified in tissue; serum amyloid A (SAA) and transthyretin (TTR) were found in serum.

CONCLUSION

Individual prediction of therapy benefit and selecting patients for ICT based on molecular biological profiles appear to be feasible in the future.

Paraffin-embedded tissue is less accurate than frozen section analysis for determining VHL mutational status in sporadic renal cell carcinoma

INTRODUCTION

Literature controversies exist regarding the prognostic value of VHL mutations. The objective was to compare paraffin-embedded and frozen section specimens for VHL mutations detection and to evaluate the reliability of DNA analysis in formalin-fixed tissues.

METHODS

Seventy-six patients with clear cell renal cell carcinoma (RCC) previously assessed for VHL status from frozen samples were included. Seventy-three tumor samples were known to be mutated for VHL. DNA was extracted and an electrophoresis was performed to determine DNA quality. The whole coding sequence was synthesized by double PCR amplification followed by sequencing. Sequencing results were compared with those previously determined from frozen samples.

RESULTS

DNA could be extracted from the 76 paraffin samples. DNA quality was highly degraded and significantly less amplified by PCR in 34.2%, resulting in no sequence available for analysis in 57.7% and discordance with frozen samples in 42.3% of the cases respectively. VHL mutations were found in 52.1% of the whole paraffin samples whereas 98% were mutated; 72% could be sequenced, resulting in 69.1% of VHL mutations in this subset. Only half of observed mutations were fully consistent with frozen analysis in the 3 exons. Neomutations were found in 10.5% and 28.9% of known mutations in frozen samples were not detected in paraffin blocks. Only DNA quality significantly influenced PCR amplification and sequencing.

CONCLUSION

Tumoral DNA extraction and VHL mutation analysis can be performed from formalin-fixed paraffin-embedded (FFPE) tissue in RCC. But mutations identified tissues are not strictly concordant with those from frozen analysis and therefore results obtained from FFPE samples should be interpreted with care.

Prognostic factors in renal cell carcinoma

PURPOSE

Renal cell carcinoma (RCC) is a very heterogeneous disease with widely varying prognosis. An accurate knowledge of the individual risk of disease progression and mortality after treatment is essential to counsel patients, plan individualized surveillance protocols and select patients for adapted treatment schedules and new clinical trials.

METHODS

A systematic review of the literature on prognostic factors of localized and metastatic RCC was performed.

RESULTS

Prognostic factors in RCC include anatomical (TNM classification, tumor size), histological (Fuhrman grade, histologic subtype), clinical (symptoms and performance status), and molecular features. All these features are not perfectly accurate when used alone. Therefore an increasing number of prognostic models or nomograms that include several combined prognostic features have been designed in order to improve predictive accuracy. UCLA Integrated Staging System (UISS) and the Mayo Clinic's SSIGN score are the two most used prognostic models for localized RCC. In the setting of metastatic RCC the classical anatomical and histological tumor features have little predictive value. However, accurate prognostic models have been designed to predict response to therapy, and progression-free and overall survival. The two most used tools to predict response to immunotherapy are the model designed by the French Group of Immunotherapy and the Motzer's model. The advent of tyrosine kinase inhibitors and antiangiogenic drugs have deeply changed the treatment of metastatic RCC. Predictive tools that are adapted to the modern targeted therapies are now needed.

CONCLUSION

There is increasing knowledge on prognostic factors of localized and metastatic RCC. Several predictive models have been developed by combining different prognostic features and are valuable tools for patient counseling, treatment decision-making and trial design. Further research is needed to assess whether the combination of classical prognostic factors with molecular features and information from gene and protein expression profiling can increase the predictive accuracy of the current prognostic models.

Cancer-specific and non-cancer-related mortality rates in European patients with T1a and T1b renal cell carcinoma

OBJECTIVE

To examine cancer-specific and non-cancer-related mortality rates in 451 patients with T1a-bN0M0 renal cell carcinoma (RCC) treated with either radical or partial nephrectomy (RN or PN) in Europe.

PATIENTS AND METHODS

Between 1987 and 2007, 451 patients with T1a-bN0M0 RCC were treated for histologically confirmed RCC with RN or PN at one of seven participating European institutions. The preoperative American Society of Anesthesiology (ASA) score was available for all patients and was used to control for baseline comorbidities. The preoperative glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease study group equation. We used univariate and multivariate competing-risks regression analyses to test the effect of the ASA score, GFR, T stage (T1a vs T1b) and nephrectomy type (RN or PN) on RCC-specific mortality and non-RCC-related mortality.

RESULTS

In patients with T1a-b RCC cancer- specific mortality was unaffected by stage, nephrectomy type or GFR. Conversely, non-RCC-related mortality was strongly affected by the ASA score and GFR. Unlike in a previous report, nephrectomy type did not affect non-RCC-related mortality. This lack of significance relative to RN may stem from the relatively high rate of PN use in the present series.

CONCLUSION

PN or RN virtually eliminate the risk of cancer-specific mortality in patients with T1a-b RCC. Poor preoperative ASA score and impaired renal function appear to represent relative contra-indications to surgical management of T1a-b lesions.

Molecular targets and targeted therapies in bladder cancer management

Bladder cancer remains a significant health problem. Currently, conventional histopathologic evaluation criteria (tumor grade and stage) are limited in their ability to accurately predict tumor behavior. A significant number of patients with muscle-invasive or extravesical disease treated by radical cystectomy alone die of metastasis. Intense research efforts are being made to better identify and categorize tumors by their molecular alterations and biological characteristics. A majority of the aggressive, invasive bladder carcinomas have alterations in the p53 and retinoblastoma pathways that regulate the cell cycle by interacting with signal transduction pathways. Angiogenesis further contributes to the neoplastic growth by providing a constant supply of oxygen and nutrients. It is becoming apparent that the accumulation of genetic and molecular changes ultimately determines a tumor's phenotype and subsequent clinical behavior. We provide a contemporary outline of our current understanding of the molecular and genetic events associated with tumorigenesis and progression. We emphasize the ways by which molecular biology is likely to affect the development of future therapies that will be able to target molecular alterations in individual tumors based on their respective profiles. The current status of targeted therapies for bladder cancer is also presented as well as the ongoing clinical trials.

Race affects access to nephrectomy but not survival in renal cell carcinoma

OBJECTIVES

To assess whether, in contemporary patients with renal cell carcinoma (RCC), access to nephrectomy is the same between the Blacks and Whites, and that there is no difference in mortality after stratification for treatment type.

PATIENTS AND METHODS

The effect of race has received little attention in RCC; only two reports have addressed and suggested the presence of racial disparities, including access to nephrectomy and survival after nephrectomy, where Black patients were disadvantaged relative to Whites. We used the Surveillance, Epidemiology and End Results data from 12 516 patients of all stages diagnosed and treated for RCC between 2000 and 2004. The effect of race (Black vs White) on nephrectomy rate was addressed in logistic regression and binomial regression models, and Cox regression models tested the effect of race on overall survival.

RESULTS

Black patients were 50% less likely to have a nephrectomy than their White counterparts. However, race had no effect on overall survival when the entire cohort was assessed, as well as in subgroups of patients with or without nephrectomy.

CONCLUSIONS

Although race is a determinant of access to nephrectomy, it should not be interpreted as a barrier to care, as survival was unaffected by race in patients having a nephrectomy or not. Instead, race might represent a proxy of comorbidity and life-expectancy, which represent surgical selection criteria for nephrectomy.

Can tyrosine kinase inhibitors be discontinued in patients with metastatic renal cell carcinoma and a complete response to treatment? A multicentre, retrospective analysis

BACKGROUND

Discontinuation of treatment with tyrosine kinase inhibitors (TKIs) and readministration in case of recurrence could improve quality of life (QoL) and reduce treatment costs for patients with metastatic renal cell carcinoma (mRCC) in which a complete remission (CR) is achieved by medical treatment alone or with additional resection of residual metastases.

OBJECTIVE

To evaluate whether TKIs can be discontinued in these selected patients with mRCC.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective analysis of medical records and imaging studies was performed on all patients with mRCC treated with TKIs (n=266) in five institutions. Patients with a CR under TKI treatment alone or with additional metastasectomy of residual disease following a partial response (PR), in which TKIs were discontinued, were included in the analysis. Outcome criteria analysed were time to recurrence of previous metastases, occurrence of new metastases, symptomatic progression, improvement of adverse events, and response to reexposure to TKIs.

INTERVENTIONS

Sunitinib 50mg/day for 4 wk on and 2 wk off, sorafenib 800mg/day.

MEASUREMENTS

Response according to Response Evaluation Criteria in Solid Tumours (RECIST).

RESULTS AND LIMITATIONS

We identified 12 cases: 5 CRs with sunitinib, 1 CR with sorafenib, and 6 surgical CRs with sunitinib followed by residual metastasectomy. Side-effects subsided in all patients off treatment. At a median follow-up of 8.5 mo (range: 4-25) from TKI discontinuation, 7 of 12 patients remained without recurrence and 5 had recurrent disease, with new metastases in 3 cases. Median time to progression was 6 mo (range: 3-8). Readministration of TKI was effective in all cases. The study is limited by small numbers and retrospective design.

CONCLUSIONS

Discontinuation of TKI in patients with mRCC and CR carries the risk of progression with new metastases and potential complications. Further investigation in a larger cohort of patients is warranted before such an approach can be regarded as safe.

Stage-specific effect of nodal metastases on survival in patients with non-metastatic renal cell carcinoma

OBJECTIVE

To quantify the survival disadvantage related to the presence of exclusive nodal metastases (eNM) in patients with otherwise non-metastatic (M0) renal cell carcinoma (RCC).

PATIENTS AND METHODS

Data were retrieved from 12 institutional databases and yielded 3507 patients with T1-3N1-2M0 RCC treated with partial or radical nephrectomy. Cox regression analyses relied on T stage, Fuhrman grade and presence of eNM. Data were analysed using univariable, multivariable and stratified analyses.

RESULTS

Overall 165 (4.7%) patients had eNM; of 2023 patients of stage T1, 23 (1.1%) had eNM, vs 20 of 448 (4.5%) for T2 and 122 of 993 (12.3%) for T3. In univariable analyses the presence of eNM increased the rate of cancer specific mortality (CSM) by 7.1 times. After adjusting for T stage and Fuhrman grade, in all patients eNM increased the rate of CSM by 3.2 times. In stratified analyses adjusted for Fuhrman grade, the increase in CSM related to the presence of eNM was 28.9, 4.3 and 2.5 times (all P < 0.001) for stages T1, T2 and T3, respectively.

CONCLUSIONS

From the prognostic perspective, staging lymphadenectomy appears of most value in patients with T1-2 RCC, but the low prevalence of eNM questions the practical applicability of nodal staging in those patients. Conversely, in patients with T3 RCC, the prevalence and the prognostic impact of eNM might make a staging lymphadenectomy worthwhile.

Update on the medical treatment of metastatic renal cell carcinoma

CONTEXT

Metastatic renal cell carcinoma (mRCC) has long been treated only by immunotherapy with good results only in a small population of patients. In recent years, major improvements in treatment possibilities have occurred with the advent of anti-angiogenic drugs. In the past 2 yr, pivotal phase III trials have confirmed this major breakthrough by increasing the progression-free survival rates and/or overall survival rates provided by sunitinib, sorafenib, and bevacizumab, and more recently by the mTOR (mammalian target of rapamycin) inhibitors temsirolimus and everolimus.

OBJECTIVE

To update the previous review on smart drugs published in the European Journal in 2006 (Patard JJ, et al. Understanding the importance of smart drugs in renal cell carcinoma. Eur Urol 2006; 49:633-43).

EVIDENCE ACQUISITION

Critical review of published literature 2006-2008 (Pubmed website search words: renal cell carcinoma and/or targeted therapy and prospective trials) and more recent meeting abstracts (American Society of Clinical Oncology 2007). Quality assessment included prospective phase I-III trials and critical evaluations with low numbers of patients, retrospective analyses, and slide presentations of meeting abstracts.

EVIDENCE SYNTHESIS

This review presents the current situation and provides more recent data on sequential treatment, the association of targeted drugs, and the treatment of non-clear-cell histologies.

CONCLUSIONS

Treatment of mRCC with targeted therapy centers on at least two major pathways: angiogenesis and mTOR involving inhibiting drugs that may be used alone, in combination, or sequentially.

Mathematical models for prognostic prediction in patients with renal cell carcinoma

OBJECTIVES

The objectives of this study are to catalogue all models developed to predict survival of RCC patients and to identify the ones to be used in different situations.

METHODS

A systematic review was performed searching with a free text and MeSH strategy 3 electronic databases. For each model, the following parameters were identified: number, features of the patients; evaluation endpoints; clinical and/or pathological variables included; concordance indexes (cI).

RESULTS

The research retrieved 156 records. Eleven articles proposed new models, 5 articles external validations. We retrieved 2 mathematical models including clinical variables only (Yaycioglu, cI 0.651; Cindolo, cI 0.672); 2 algorithms including also pathological variables (SSIGN, cI 0.819; UISS, cI 0.79-0.84), 5 nomograms (Kattan, cI 0.76-0.86; Sorbellini, cI 0.82; Kim 2004, cI 0.79, Kim 2005, cI 0.68; Karakiewicz, cI 0.86); 2 algorithms for patients with metastatic disease (Motzer, Leibovich).

CONCLUSIONS

The SSIGN was the most accurate algorithm for conventional RCC, while the UISS allowed the evaluation of patients regardless of tumor histotype. The Sorbellini nomogram is applicable only for patients with conventional RCC, while the Kattan and Karakiewicz nomograms also provide information for other histotypes. Metastatic patients can be evaluated with Leibovich and Motzer algorithms. Two models combine molecular markers and clinical features (Kim 2004-2005).

High Frequency of Intracerebral Hemorrhage in Metastatic Renal Carcinoma Patients with Brain Metastases Treated with Tyrosine Kinase Inhibitors Targeting the Vascular Endothelial Growth Factor Receptor

OBJECTIVES

To report the high incidence of intracerebral hemorrhage (ICH) in patients with metastatic renal cell carcinoma (RCC) treated with the tyrosine kinase inhibitors targeting the vascular endothelial growth factor receptor (VEGFR).

METHODS AND RESULTS

Between October 2005 and December 2006, 67 patients with metastatic RCC were treated with sorafenib or sunitinib at the Montpellier Cancer Center in compassionate access programs. The medical records of five (7%) patients who died of ICH during therapy were reviewed retrospectively. Four of them had known brain metastases. Previous radiation therapy had been indicated in two patients. Two patients had a history of hypertension. Death from ICH occurred in the first 2 wk following the onset of treatment. Three other patients with brain metastases who received sorafenib or sunitinib during the same period did not experience ICH.

CONCLUSIONS

The frequency of fatal ICH in RCC patients with brain metastases treated with tyrosine kinase inhibitors targeting the VEGFR seems high. Prospective clinical trials will be necessary for assessing the true incidence and predictive factors related to this toxicity.

Patients with renal cell carcinoma nodal metastases can be accurately identified: external validation of a new nomogram

Outcome of patients with renal cell carcinoma nodal metastases (NM) is substantially worse than that of patients with localized disease. This justifies more thorough staging and possibly more aggressive treatment in those at risk of or with established NM. We developed and externally validated a nomogram capable of highly accurately predicting renal cell carcinoma NM in patients without radiographic evidence of distant metastases. Age, symptom classification, tumour size and the pathological nodal stage were available for 4,658 individuals. The data of 2,522 (54.1%) individuals from 7 centers were used to develop a multivariable logistic regression model-based nomogram predicting the individual probability of NM. The remaining data from 2,136 (45.9%) patients from 5 institutions were used for external validation. In the development cohort, 107/2,522 (4.2%) had lymph node metastases vs. 100/2,136 (4.7%) in the external validation cohort. Symptom classification and tumour size were independent predictors of NM in the development cohort. Age failed to reach independent predictor status, but added to discriminant properties of the model. A nomogram based on age, symptom classification and tumour size was 78.4% accurate in predicting the individual probability of NM in the external validation cohort. Our nomogram can contribute to the identification of patients at low risk of NM. This tool can help to risk adjust the need and the extent of nodal staging in patients without known distant metastases. More thorough staging can hopefully better select those in whom adjuvant treatment is necessary. (c) 2007 Wiley-Liss, Inc.

[Renal cell carcinoma and antiangiogenic therapies]

Until 2006, immunotherapy (interferon-alpha or interleukin 2) was the standard medical treatment for metastatic renal cell carcinoma (RCC), and its results were disappointing: despite a few cases of complete response with prolonged survival, median survival was one year. Better understanding of the molecular mechanisms of tumor angiogenesis, especially in clear cell carcinoma, has led to the development of multiple targeted therapies to inhibit key effectors: vascular endothelial growth factor (VEGF), VEGF receptor, and mTOR (target of rapamycin). Two inhibitors targeting several protein kinases, including the VEGF receptor, have increased progression-free survival in patients with metastatic RCC and are now commercially available: sunitinib (Sutent) as first-line treatment and sorafenib (Nexavar) as second-line treatment. These targeted therapies will certainly affect overall survival, but it is too early for any firm conclusions. Their side-effects, usually low or moderate, include asthenia, anorexia, diarrhea, hand-and-foot syndrome and hypertension. Optimal management is required to ensure prolonged exposure. Other drugs have been effective: bevacizumab (Avastin), a monoclonal antibody inhibiting VEGF, increases progression-free survival as second-line treatment, and temsirolimus (Torisel), an mTOR protein kinase inhibitor, increases overall survival in the population of patients with poor prognosis. These targeted drugs will serve as the basis for development of future therapeutic strategies.

Toxicities associated with the administration of sorafenib, sunitinib, and temsirolimus and their management in patients with metastatic renal cell carcinoma

OBJECTIVE

To provide a systematic review of the side effects associated with sorafenib, sunitinib, and temsirolimus and to provide an outline of possible preventive or therapeutic measures.

METHODS

We performed a PubMed-based systematic review of side effects associated with the three agents and relied on product monographs and prescribing information to provide an outline of treatments aimed at reducing these toxicities.

RESULTS

Side effects range from <1% to 72%. Grade 3/4 side effects are less common and range from <1% to 13% for sorafenib, <1% to 16% for sunitinib, and 1% to 20% for temsirolimus. Overall, sunitinib causes the most grade 3/4 side effects and sorafenib causes the fewest grade 3/4 side effects, although head-to-head trials are required to compare safety profiles of all three kinase inhibitors. Virtually all side effects can be managed effectively.

CONCLUSION

Prevention, recognition, and prompt management of side effects are of key importance and avoid unnecessary dose reductions, which may undermine treatment efficacy.