Characterization of tumor thrombus in renal cell carcinoma with prostate specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT)

Value of [68Ga]Ga-PSMA-11 PET/CT in Reflecting the Intra- and Intertumor Heterogeneity of Neovascularization in Clear Cell Renal Cell Carcinoma

Prostate-specific membrane antigen (PSMA) is a potential target for the diagnosis and treatment of angiogenesis in clear cell renal cell carcinoma (ccRCC). We aimed to investigate the degree of PSMA signal variability in ccRCC and assess its correlation with neovascularization in the tumor microenvironment. We included 120 patients with suspected renal tumors who underwent [68Ga]Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) scan before surgery in this retrospective study, including 98 ccRCC, 17 non-ccRCC, and 5 benign diseases. We compared the maximum standard uptake value (SUVmax) and tumor-to-liver ratio (TLR) of primary lesions in different groups and analyzed the diagnostic efficacy of PSMA imaging for ccRCC. The coefficient of variation (CV) of SUVmax, which reflects intertumor heterogeneity, and volume ratio (VR), which reflects intratumor heterogeneity, were obtained from PET imaging. We analyzed the correlation between SUVmax, PSMA immunohistiochemical (IHC) staining, microvessel density (MVD), and serum vascular endothelial growth factor (VEGF) and compared the inter- and intratumor heterogeneity of primary lesions and metastases. In our study, ccRCC showed significantly higher SUVmax and TLR compared to non-ccRCC and benign diseases (F = 14.48, p < 0.001; F = 14.49, p < 0.001). PSMA IHC staining exhibited moderate correlation with SUVmax (r = 0.421, p = 0.021) and MVD (r = 0.518, p = 0.003), but it was not correlated with serum VEGF (r = -0.003, p = 0.989). SUVmax had a moderate correlation with MVD (r = 0.448, p = 0.013) and serum VEGF (r = 0.345, p = 0.020). Serum VEGF exhibited a weak correlation with MVD (r = 0.338, p = 0.145). Based on the correlation, the SUVmax-to-angiogenesis model was validated. The mean SUVmax values of primary lesions, bone metastases, and tumor thrombi were 16.13, 18.69, and 6.02, respectively. The CV of the mean SUVmax was 58.5%, 55.9%, and 80.6%. The mean VR values of primary lesions, bone metastases, and tumor thrombi were 0.33, 0.46, and 0.75, respectively. The CV of the mean VR was 81.8%, 41.3%, and 26.7%. The SUVmax of primary lesions was significantly correlated with corresponding bone metastases and tumor thrombi (r = 0.52, p = 0.011; r = 0.87, p = 0.024). The SUVmax of primary lesion in localized ccRCC and advanced ccRCC showed no significant difference (p = 0.251), while the VR was significantly different (p = 0.049). In conclusion, [68Ga]Ga-PSMA-11 PET/CT is an effective molecular imaging tool for assessing angiogenesis and its heterogeneity and differentiating ccRCC. The SUVmax of primary lesions was significantly correlated with PSMA IHC staining, MVD, and serum VEGF. The intertumor heterogeneity of tumor thrombi was significantly higher than that of primary lesions and bone metastases. Primary lesions exhibited the highest intratumor heterogeneity, and lesions with high intratumor heterogeneity showed invasive behavior. PSMA uptake by primary lesions has a positive effect on metastasis.

Theranostics in Renal Cell Carcinoma-A Step Towards New Opportunities or a Dead End-A Systematic Review

Background: Renal cell carcinoma is one of the most aggressive urogenital malignancies, with an increasing number of cases worldwide. The majority of cases are diagnosed at an advanced stage, as this form of growth is typically silent. An accurate evaluation of the extent of the disease is crucial for selecting the most appropriate treatment approach. Nuclear medicine imaging is increasingly being applied in oncological diagnostics, prompting ongoing research into renal cell carcinoma markers that could serve as a foundation for theranostic approaches in this disease. Positron emission tomography/computed tomography imaging with prostate-specific membrane antigen (PSMA) ligands has already demonstrated successful utility in diagnosis of other cancers, including prostate cancer and gliomas. Emerging evidence of high sensitivity and specificity in detecting renal cell carcinoma lesions provides a suitable foundation for its application in both the diagnosis and subsequent management of this malignancy. Methods: This systematic review synthesizes the current scientific evidence on the molecular imaging of renal cell carcinoma using PSMA ligands, emphasizing the potential future applications of this imaging marker in theranostic approaches. Results and Conclusions: Based on a systematic review of the literature, it appears that PET/CT with PSMA ligands has the potential to surpass traditional imaging techniques in diagnostic accuracy while also providing valuable prognostic information.

Renal Cell Carcinoma With Tumor Thrombus Extending Into the Inferior Vena Cava and the Right Atrium Demonstrated by 68 Ga-DOTATATE PET/CT

ABSTRACT

Approximately 10% of all renal cell carcinoma (RCC) patients develop a venous tumor thrombus, a major negative prognostic factor. Surgical excision is commonly required for RCC patients with tumor thrombus. Accurate preoperative diagnosis and assessment of tumor thrombus level is vital because the level of thrombus may influence treatment decisions. MRI, contrast-enhanced CT, 18 F-FDG PET/CT, and 68 Ga-PSMA PET/CT have been used to diagnose and evaluate the extent of tumor thrombus in RCC. However, no case of RCC with inferior vena cava tumor thrombus showing 68 Ga-DOTATATE uptake has been reported yet. Herein, we report a case of metastatic RCC with tumor thrombus in the inferior vena cava on 68 Ga-DOTATATE PET/CT.

The Role of Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography in Primary Staging of Selected Renal Tumours: Initial Experience in a Multicentre Cohort

BACKGROUND

Accurate primary staging of renal cancer with conventional imaging is challenging. Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) may serve to improve the accuracy of renal cancer staging.

OBJECTIVE

To determine clinicopathological and management differences for primary renal cancer staged with PSMA PET/CT in comparison to conventional imaging.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a retrospective cohort study of PSMA PET/CT scans performed for primary staging of renal cancer and incidental renal lesions at three sites in Brisbane, Australia between June 2015 and June 2020. Clinical characteristics, imaging, and histopathology were reviewed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Clinicopathological and management differences according to staging modality (PSMA PET/CT, conventional imaging) were assessed. Descriptive statistics were used to report demographics and clinical parameters. Nonparametric methods were used for statistical analysis. Fisher's exact test was used for comparison of small-cell size categorical variables.

RESULTS AND LIMITATIONS

From a total of 120 PSMA PET/CT scans, 61 were included (52 staging, 9 incidental) for predominantly males (74%) with a mean age of 65.1 yr (standard deviation 12.0). Most primary lesions (40/51) were clear-cell renal cell carcinoma (ccRCC; 98% PSMA-avid), eight were non-ccRCC (75% PSMA-avid), and three were non-RCC (oncocytoma; 67% PSMA-avid). PSMA PET identified a greater number of presumed metastatic lesions than conventional imaging (195 vs 160). A management change was observed for 32% of patients (20% major, 12% minor). Limitations include the retrospective design and selection bias, lack of blinding to PSMA reporting, and the use of different PSMA radiotracers.

CONCLUSIONS

PSMA PET/CT detected more metastases than conventional imaging and most renal cancers were PSMA-avid, resulting in a management change for one-third of the patients.

PATIENT SUMMARY

We looked at a newer type of scan called PSMA PET/CT for first staging of kidney cancer. We found that this detects more metastasis and helps in decisions on changes in treatment for some patients. This type of imaging is a useful addition to conventional scans in tricky cases and may help in better selection of suitable treatments, but more studies are required.

Utility of PSMA PET/CT in Staging and Restaging of Renal Cell Carcinoma: A Systematic Review and Metaanalysis

Prostate-specific membrane antigen (PSMA) is expressed in the neovasculature of multiple solid tumors, including renal cell carcinoma (RCC). Studies have demonstrated promising results on the utility of PSMA-targeted PET/CT imaging in RCC. This report aims to provide a systematic review and metaanalysis on the utility and detection rate of PSMA PET/CT imaging in staging or evaluation of primary RCC and restaging of metastatic or recurrent RCC. Methods: Searches were performed in PubMed, Embase, and abstract proceedings (last updated, August 2023). Studies that provided a lesion-level detection rate of PSMA radiotracers in staging or restaging of RCC were included in the metaanalysis. The overall pooled detection rate with a 95% CI was estimated, and subgroup analysis was performed when feasible. Results: Nine studies comprising 152 patients (133 clear cell RCC [ccRCC], 19 other RCC subtypes) were included in the metaanalysis. The pooled detection rate of PSMA PET/CT in evaluation of primary or metastatic RCC was estimated to be 0.83 (95% CI, 0.67-0.92). Subgroup analysis showed a pooled PSMA detection rate of 0.74 (95% CI, 0.57-0.86) in staging or evaluation of primary RCC lesions and 0.87 (95% CI, 0.73-0.95) in restaging of metastatic or recurrent RCC. Analysis based on the type of radiotracer showed a pooled detection rate of 0.85 (95% CI, 0.62-0.95) for 68Ga-based PSMA tracers and 0.92 (95% CI, 0.76-0.97) for 18F-DCFPyL PET/CT. Furthermore, in metastatic ccRCC, the available data support a significantly higher detection rate for 18F-DCFPyL PET/CT than for conventional imaging modalities (2 studies). Conclusion: Our preliminary results show that PSMA PET/CT could be a promising alternative imaging modality for evaluating RCC, particularly metastatic ccRCC. Large prospective studies are warranted to confirm clinical utility in the staging and restaging of RCC.

Clinical impact of Prostate-Specific Membrane Antigen Positron Emission Tomography (PET) on intensification or deintensification of advanced renal cell carcinoma management

PURPOSE

There is an emerging role of the use of Prostate-Specific Membrane Antigen (PSMA) Positron Emission Tomography (PET) in renal cell carcinoma. Herein, we report our experience in use of PSMA PET in recurrent or metastatic renal cell carcinoma (RCC).

METHODS

A retrospective analysis of all patients who underwent PSMA PET for suspected recurrent or de-novo metastatic RCC between 2015 and 2020 at three institutions was performed. The primary outcome was change in management (intensification or de-intensification) following PSMA PET scan. Secondary outcomes included histopathological correlation of PSMA avid sites, comparison of sites of disease on PSMA PET to diagnostic CT and time to systemic treatment.

RESULTS

Management of Renal Cell Carcinoma With Intra-atrial Tumour Thrombus: A Case Report

Renal cell cancer (RCC) is at times associated with intravascular tumour thrombus (TT), which in rare cases can extend to the right atrium. The management of RCC with intravascular tumour thrombus is complex and requires a multidisciplinary approach involving urologists, vascular surgeons, and cardiologists. The pre-operative workup is extensive and includes imaging studies to determine the extent of the tumour thrombus and assess the patient's overall health status. Here, we present a case report detailing the operative and perioperative management of a patient presenting with renal cell cancer and intravascular TT.

Hot topics in renal cancer pathology: implications for clinical management

INTRODUCTION

The updated European Association of Urology (EAU) Guidelines issued a weak recommendation for adjuvant pembrolizumab for patients with high-risk operable clear cell Renal Cell Carcinoma (ccRCC). High risk of recurrence was defined, as per protocol-criteria, as T2 with nuclear grade 4 or sarcomatoid differentiation, T3 or higher, regional lymph node metastasis, or stage M1 with no evidence of disease. Considering the heterogeneous population included in the recommendation, it has been questioned if adjuvant pembrolizumab may lead to overtreatment of some patients as well as undertreatment of patients with worse prognosis.

AREAS COVERED

In this review, we discuss the issues related to the assessment of pathological features required to identify those patients harboring a high-risk tumor, highlighting the issue related to interobserver variability and discuss the currently available prognostic scoring systems in ccRCC.

EXPERT OPINION

PPathologist assessment of prognostic features suffers from interobserver variability which may depend on gross sampling and the pathologist's expertise. The presence of clear cell feature is not sufficient criteria by itself to define ccRCC since clear cell can be also found in other histotypes. Application of molecular biomarkers may be useful tools in the near future to help clinicians identify patients harboring tumors with worse prognosis.

Impact of Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography in the Management of Oligometastatic Renal Cell Carcinoma

Background

Prostate-specific membrane antigen (PSMA) is overexpressed in the neovasculature of renal cell carcinoma (RCC). However, there remains limited evidence regarding the use of PSMA positron emission tomography/computed tomography (PET/CT) in RCC.

Objective

To assess the impact of PSMA PET/CT in the management of metastatic RCC.

Design, setting, and participants

This was a retrospective review of patients who underwent PSMA PET/CT from 2014 to 2020 for restaging or suspected metastatic RCC in a tertiary academic setting.

Outcome measurements and statistical analysis

Management plans before and after PSMA PET/CT were recorded. Impact was classified as high (change of treatment intent, modality, or site), medium (change in treatment method), or low. Secondary outcomes included the patient-level detection rate, PSMA PET/CT parameters, sensitivity, and comparison to CT and, if available, fluorodeoxyglucose (FDG) PET/CT.

Results and limitations

Sixty-one patients met the inclusion criteria, of whom 54 (89%) had clear cell RCC. PSMA-positive disease was detected in 51 patients (84%). For 30 patients (49%) there was a change in management due to PSMA PET/CT (high impact, 29 patients, 48%). In 15 patients (25%), more metastases were detected on PSMA PET/CT than on CT. The sensitivity of combined PSMA PET/CT and diagnostic CT was 91% (95% confidence interval 77–98%). In a subcohort of 40 patients, the detection rate was 88% for PSMA and 75% for FDG PET/CT (p = 0.17). The maximum standardised uptake value (SUV_max) was higher for PSMA than for FDG PET/CT (15.2 vs 8.0; p = 0.02). Limitations include selection bias due to the retrospective design, and a lack of corresponding histopathology for all patients.

Conclusions

PSMA PET/CT is a promising imaging modality in metastatic RCC and led to a change in management in 49% of patients. PSMA PET/CT detected additional metastases compared to CT in 25% of patients and registered a significantly higher SUV_max than FDG PET/CT. Prospective studies are required to further define its role.

Patient summary

We report on a group of patients undergoing a new type of imaging for suspected advanced kidney cancer, called PSMA PET/CT. This imaging changed the management plan in 49% of the patients. PSMA PET/CT detected metastases in 84% of our patients and detected more metastases than computed tomography imaging in 25%.

Tumor thrombus formation in the right common iliac vein after radical proctectomy in a patient with rectal cancer: a case report

Background

Intravascular tumor thrombi are mainly found in patients with liver cancer or renal carcinoma but rarely occur in those with rectal cancer.

Case presentation

This is a case report of a 58-year-old woman with a swollen right lower extremity 14 months after radical resection for rectal cancer. Although ultrasonography indicated the presence of deep venous thrombosis (DVT) located in the right common iliac vein, interventional angiography showed that a circular mass, considered a tumor thrombus, was located in the right common iliac vein. The tumor thrombus was cured by interventional therapy, and the pathological report confirmed that the metastatic tumor thrombus originated from the rectal cancer. The patient underwent concurrent chemoradiotherapy and systemic therapy. However, right lung, retroperitoneum, and 2nd sacral vertebral metastases were discovered during follow-up.

Conclusion

The correct diagnosis of a tumor thrombus and its differentiation from DVT can prevent incorrect treatment and prolong the survival of patients with rectal cancer.