Diagnostic value of F-18 FDG PET/CT for local and distant disease relapse surveillance in surgically treated RCC patients: Can it aid in establishing consensus follow up strategy?

Metastatic Renal Cell Carcinoma to Pancreas: Case Series and Review of the Literature

Metastasis to the pancreas represents a small proportion of all pancreatic malignancies. Among primary tumors that metastasize to the pancreas, renal cell carcinoma (RCC) is one of the most common causes of metastatic pancreatic lesions. We herein report a case series of three patients with pancreatic metastasis from RCC. The first is a 54-year-old male with a history of left nephrectomy for RCC, in whom an isthmic pancreatic mass suggestive of a neuroendocrine lesion was found during oncological follow-up. Endoscopic ultrasound (EUS)-guided fine needle biopsy (FNB) identified pancreatic metastasis of RCC and the patient was referred for surgery. The second case is a 61-year-old male, hypertensive, diabetic, with left nephrectomy for RCC six years previously, who complained of weight loss and was found with a hyperenhancing mass in the head of the pancreas and a lesion with a similar pattern in the gallbladder. EUS-FNB from the pancreas proved to be a metastatic pancreatic lesion. Cholecystectomy and treatment with tyrosine kinase inhibitors were recommended. The third case is a 68-year-old dialysis patient referred for evaluation of a pancreatic mass, also confirmed by EUS-FNB, who was started on sunitinib treatment. We report a literature summary on epidemiology and clinical features, diagnosis and differential diagnosis and treatment and outcomes in pancreatic metastasis of RCC.

Metastatic Renal Cell Carcinoma to Pancreas: Case Series and Review of the Literature

Metastasis to the pancreas represents a small proportion of all pancreatic malignancies. Among primary tumors that metastasize to the pancreas, renal cell carcinoma (RCC) is one of the most common causes of metastatic pancreatic lesions. We herein report a case series of three patients with pancreatic metastasis from RCC. The first is a 54-year-old male with a history of left nephrectomy for RCC, in whom an isthmic pancreatic mass suggestive of a neuroendocrine lesion was found during oncological follow-up. Endoscopic ultrasound (EUS)-guided fine needle biopsy (FNB) identified pancreatic metastasis of RCC and the patient was referred for surgery. The second case is a 61-year-old male, hypertensive, diabetic, with left nephrectomy for RCC six years previously, who complained of weight loss and was found with a hyperenhancing mass in the head of the pancreas and a lesion with a similar pattern in the gallbladder. EUS-FNB from the pancreas proved to be a metastatic pancreatic lesion. Cholecystectomy and treatment with tyrosine kinase inhibitors were recommended. The third case is a 68-year-old dialysis patient referred for evaluation of a pancreatic mass, also confirmed by EUS-FNB, who was started on sunitinib treatment. We report a literature summary on epidemiology and clinical features, diagnosis and differential diagnosis and treatment and outcomes in pancreatic metastasis of RCC.

Radiogenomics in Renal Cancer Management-Current Evidence and Future Prospects

Renal cancer management is challenging from diagnosis to treatment and follow-up. In cases of small renal masses and cystic lesions the differential diagnosis of benign or malignant tissues has potential pitfalls when imaging or even renal biopsy is applied. The recent artificial intelligence, imaging techniques, and genomics advancements have the ability to help clinicians set the stratification risk, treatment selection, follow-up strategy, and prognosis of the disease. The combination of radiomics features and genomics data has achieved good results but is currently limited by the retrospective design and the small number of patients included in clinical trials. The road ahead for radiogenomics is open to new, well-designed prospective studies, with large cohorts of patients required to validate previously obtained results and enter clinical practice.

[18F]FDG PET/CT: Lung Nodule Evaluation in Patients Affected by Renal Cell Carcinoma

Renal Cell Carcinoma (RCC) is generally characterized by low-FDG avidity, and [¹⁸F]FDG-PET/CT is not recommended to stage the primary tumor. However, its role to assess metastases is still unclear. The aim of this study was to evaluate the diagnostic accuracy of [¹⁸F]FDG-PET/CT in correctly identifying RCC lung metastases using histology as the standard of truth. The records of 350 patients affected by RCC were retrospectively analyzed. The inclusion criteria were: (a) biopsy- or histologically proven RCC; (b) Computed Tomography (CT) evidence of at least one lung nodule; (c) [¹⁸F]FDG-PET/CT performed prior to lung surgery; (d) lung surgery with histological analysis of surgical specimens; (e) complete follow-up available. A per-lesion analysis was performed, and diagnostic accuracy was reported as sensitivity and specificity, using histology as the standard of truth. [¹⁸F]FDG-PET/CT semiquantitative parameters (Standardized Uptake Value [SUVmax], Metabolic Tumor Volume [MTV] and Total Lesion Glycolysis [TLG]) were collected for each lesion. Sixty-seven patients with a total of 107 lesions were included: lung metastases from RCC were detected in 57 cases (53.3%), while 50 lesions (46.7%) were related to other lung malignancies. Applying a cut-off of SUVmax ≥ 2, the sensitivity and the specificity of [¹⁸F]FDG-PET/CT in detecting RCC lung metastases were 33.3% (95% CI: 21.4-47.1%) and 26% (95%CI: 14.6-40.3%), respectively. Although the analysis demonstrated a suboptimal diagnostic accuracy of [¹⁸F]FDG-PET/CT in discriminating between lung metastases from RCC and other malignancies, a semiquantitative analysis that also includes volumetric parameters (MTV and TLG) could support the correct interpretation of [¹⁸F]FDG-PET/CT images.

Prognostic Significance of 18F-FDG PET/CT Imaging in Survival Outcomes in Patients with Renal Cell Carcinoma

Objectives:

Renal cell carcinoma (RCC) comprises 85%-90% of primary renal malignant tumors originating from the renal tubular epithelium and has different genetic characteristics. This study aimed to investigate the potential predictive role of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and metabolic parameters in overall survival (OS) analysis in patients with RCC.

Methods:

¹⁸F-FDG PET/CT images of 100 patients performed for initial staging before surgical or oncological treatments were analyzed retrospectively. Maximum standard uptake value (SUV_max-T) of the primary tumor was calculated and its relationship to patient survival was analyzed. The median follow-up time was 5.61 years (0.01-8.7 years).

Results:

SUV_max-T levels in the patients ranged from 2.1 to 48.9 (median 5.9, mean 9.0±7.9). SUV_max-T was significantly higher in RCC-related death more positive than in the negative cases (p<0.001). However, there was not any statistical significance for gender and pathological subtypes on the survival outcomes of patients (p=0.264 and p=0.784). The patients’ 1-year, 3-year, and 5-year OS rates were 71%, 61%, and 57%, respectively. The highest action of SUV_max-T for estimating OS was a cut-off level of 5.4, which maintained sensitivity and specificity of 81% and 75%, respectively. However, cancer staging remained independent significance for OS (p<0.001).

Conclusion:

SUV_max of primary tumor and cancer stage were demonstrated as significant prognostic factors for OS in patients with RCC. Evaluation of 18F-FDG accumulation with PET/CT may help plan treatment strategies and predict survival outcomes of these patients at diagnosis.

ACR Appropriateness Criteria® Post-Treatment Follow-up and Active Surveillance of Clinically Localized Renal Cell Carcinoma: 2021 Update

Renal cell carcinoma (RCC) accounts for most malignant renal tumors and is considered the most lethal of all urologic cancers. For follow-up of patients with treated or untreated RCC and those with neoplasms suspected to represent RCC, radiologic imaging is the most valuable component of surveillance, as most relapses and cases of disease progression are identified when patients are asymptomatic. Understanding the strengths and limitations of the various imaging modalities for the detection of disease, recurrence, or progression is essential when planning follow-up regimens. This document addresses the appropriate imaging examinations for asymptomatic patients who have been treated for RCC with radical or partial nephrectomy or ablative therapies. It also discusses the appropriate imaging examinations for asymptomatic patients with localized biopsy-proven or suspected RCC undergoing active surveillance. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Molecular Imaging of Renal Cell Carcinoma in Precision Medicine

Renal cell carcinoma (RCC) is the sixth most common cancer among men and the ninth among women, and its prognosis is closely correlated with metastasis. Targeted therapy and immunotherapy are the main adjuvant treatments for advanced RCC and require early diagnosis, precise assessment, and prediction of the therapeutic responses. Current conventional imaging methods of RCC only provide structural information rather than biological processes. Noninvasive diagnostic tools are therefore needed to image RCC early and accurately at the molecular level. Nuclear medicine imaging combines the high sensitivity of radionuclides with the high resolution of structural imaging to visualize the metabolic processes and specific targets of RCC for more accurate and reliable diagnosis, staging, prognosis prediction, and response assessment. This review summarizes the most recent applications of nuclear medicine receptor imaging and metabolic imaging in RCC and highlights future development perspectives in the field.

Role of 18F-FDG PET/CT in the assessment of therapy response and clinical outcome in metastatic renal cell carcinoma treated with tyrosine kinase inhibitors or immunotherapy

OBJECTIVE

This study aimed to determine the role and prognostic significance of 18F-FDG PET/CT on treatment response and survival outcomes in metastatic renal cell carcinoma patients treated with immunotherapy or tyrosine kinase inhibitors (TKIs).

PATIENTS AND METHODS

Forty patients scheduled for a standard treatment protocol with TKIs (n = 17; group-1) or PD-1 inhibitors (nivolumab, n = 23; group-2) were evaluated by 18F-FDG PET/CT. Peak standardized uptake value corrected for lean body mass (SULpeak) and maximum standardized uptake value (SUVmax) were calculated, and their relationship to treatment response was evaluated.

RESULTS

Complete response (CR) in three patients, partial response (PR) in two patients and stable disease (SD) in eight patients were observed in group-1, and the results were as follows for group-2: PR in seven and SD in five patients. At a mean of 17.5-month observation period (range, 7-47), 35.2% of patients progressed, and 23.5% achieved a CR, and no recurrence was observed on PET/CT scans during follow-up. Among all patients enrolled in the study, the 5-year OS in patients with progressive disease (PD) was significantly shorter than patients with clinical benefit (CB = CR and PR and SD) (P = 0.016). Significant differences in both ΔSULpeak and ΔSUVmax were found between PD versus CB (P = 0.001 and P < 0.001, respectively).

CONCLUSION

18F-FDG-PET/CT can accurately assess therapy response and predict patient outcome in metastatic RCC. 18F-FDG PET/CT may facilitate patient management by evaluating the biological and immunological responses to treatment in patients treated with TKIs or ICIs.

Role of positron emission tomography/computed tomography in the evaluation of renal cell carcinoma

Introduction:

Positron emission tomography (PET) is not a standard recommendation in most of the major guidelines for the evaluation of renal cell carcinoma (RCC). Earlier studies evaluating PET scan in patients with RCC have provided discordant results. However, with the advent of newer hybrid PET/computed tomography (CT) scanning systems, this modality has shown increased efficacy in the evaluation of primary renal masses along with the detection of extrarenal metastases, restaging recurrent RCC, and also in monitoring response to targeted therapy. We performed a systematic review of the existing literature on the role of PET scan in the evaluation of RCC.

Methodology:

We systematically searched the databases of PubMed/Medline, Embase, and Google Scholar to identify studies on the use of PET scan in RCC. Using Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, 94 full-text articles were selected, of which 54 relevant articles were then reviewed, after a consensus by the authors.

Results:

Several studies have shown similar sensitivity and specificity of fluoro-2-deoxy-2-d-glucose-PET (FDG-PET) scan as compared to conventional CT scan for the initial diagnosis of RCC, and an improved sensitivity and specificity for the detection of metastases and recurrences following curative therapy. The PET scan may also play a role in predicting the initial tumor biology and pathology and predicting the prognosis as well as the response to therapy.

Conclusion:

The current guidelines do not recommend PET scan in the staging armamentarium of RCCs. However, FDG-PET scan is as efficacious, if not better than conventional imaging alone, in the evaluation of the primary and metastatic RCC, as well as in evaluating the response to therapy, due to its ability to pick up areas of increased metabolic activity early on. Newer tracers such as ^Ga68 prostate specific membrane antigen-labeled ligands may help in opening up newer avenues of theragnostics.

PET imaging in renal cancer

PURPOSE OF REVIEW

Worldwide, over 400 000 new cases of kidney cancer were diagnosed and over 175 000 deaths anticipated in 2018. It is ranked as the 14th most common cancer in women and 9th most common in men. Imaging is important for initial detection, staging, and monitoring to assist treatment planning, but conventional anatomic imaging is limited. Although functional PET/CT has proven helpful in the diagnosis and management of many cancers, its value in renal cell carcinoma (RCC) is still in evolution.

RECENT FINDINGS

FDG is probably the most useful radiotracer in RCC, although CAIX imaging can be helpful in clear cell RCC. Current research on PET imaging agents in RCC including 89Zr bevacizumab, 89Zr geruntuximab, 18F fluoro-L-thymidine (FLT), prostate-specific membrane antigen (PSMA), 11C choline, 18F sodium fluoride (NaF), and18F fluorodeoxyglucose (FDG) have shown some interesting results for detection and prognosis of the disease.

SUMMARY

Many innovative radiotracers have been tested in RCC, but robust differentiation of primary disease from normal parenchyma remains elusive for almost all of them. The metastatic setting and response to therapy for this cancer are more favorable PET applications. Continued research in promising molecular tracers will hopefully advance both diagnostic and therapeutic strategies to ultimately eradicate RCC.

Role of Positron Emission Tomography Imaging in Metabolically Active Renal Cell Carcinoma

PURPOSE OF REVIEW

The clinical role of fluorine-18 fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) in renal cell carcinoma (RCC) is still evolving. Use of FDG PET in RCC is currently not a standard investigation in the diagnosis and staging of RCC due to its renal excretion. This review focuses on the clinical role and current status of FDG PET and PET/CT in RCC.

RECENT FINDINGS

Studies investigating the role of FDG PET in localized RCC were largely disappointing. Several studies have demonstrated that the use of hybrid imaging PET/CT is feasible in evaluating the extra-renal disease. A current review of the literature determines PET/CT to be a valuable tool both in treatment decision-making and monitoring and in predicting the survival in recurrent and metastatic RCC. PET/CT might be a viable option in the evaluation of RCC, especially recurrent and metastatic disease. PET/CT has also shown to play a role in predicting survival and monitoring therapy response.

Surgical Interventions for Renal Cell Carcinoma with Thrombus Extending into the Inferior Vena Cava: A Multidisciplinary Approach

Objective: To assess surgical strategies and the impact of a multidisciplinary approach on patients undergoing inferior vena caval thrombectomy for renal cell carcinoma and to evaluate perioperative morbidity and mortality associated with these procedures.

Methodology: A retrospective audit for all adults who underwent nephrectomy and inferior vena caval thrombectomy from January 2008 till November 2018 at a University hospital. Patients with incomplete records were excluded from the study.

Results: During the study period, 21 patients underwent inferior vena caval thrombectomy as a completion of radical nephrectomy. Most were males (19 : 2) with a mean age of 54±11.3 years. The most common surgical approach was the 11th rib flank approach (n=8) followed by midline abdominal (n=6) and Mercedes-Benz (n=5). Eight patients had level 1, 10 patients had level 2, and three patients had level 3 tumour thrombus. The cavotomy was closed primarily in 20 patients; one required inferior vena cava (IVC) reconstruction with a pericardial patch. The proximal clamp was applied below the hepatic veins for most patients. Two patients required suprahepatic clamping before thrombectomy. There was no intraoperative mortality. Five patients (24%) developed complications: two required cardiopulmonary resuscitation due to severe hypotension and were revived; one developed acute renal failure; and one patient required a damage control laparotomy for excessive oozing. There was no thirty-day mortality.

Conclusion: The IVC thrombectomy, along with radical nephrectomy for renal cell carcinoma for 1–3 level thrombus, can be performed with acceptable morbidity in a multidisciplinary team approach.