Diagnostic Value of 18F-fluorodeoxyglucose Positron Emission Tomography with Computed Tomography for Lymph Node Staging in Patients with Upper Tract Urothelial Carcinoma

FDG PET/CT in Staging and Response Evaluation of Primary Urothelial Carcinoma of the Urethra

ABSTRACT

Primary urethral urothelial carcinoma is a rare aggressive tumor with a high propensity for local invasion and regional and distal metastases. We describe the usefulness of FDG PET/CT in management of a patient with primary urethral urothelial carcinoma. FDG PET/CT at initial staging showed FDG-avid primary tumor and lymph node metastasis of the left groin, and mild or no activity of the lung metastases due to small size. FDG PET/CT after 4 cycles of chemotherapy showed progression of the primary tumor and lung metastases, partial response of the left inguinal lymphadenopathy, and multiple new sites of FDG-avid metastases.

A Systematic Review on the Diagnostic Value of Fibroblast Activation Protein Inhibitor PET/CT in Genitourinary Cancers

In contemporary oncologic diagnostics, molecular imaging modalities are pivotal for precise local and metastatic staging. Recent studies identified fibroblast activation protein as a promising target for molecular imaging across various malignancies. Therefore, we aimed to systematically evaluate the current literature on the utility of fibroblast activation protein inhibitor (FAPI) PET/CT for staging patients with genitourinary malignancies. Methods: A systematic Embase and Medline search was conducted, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) process, on August 1, 2023. Relevant publications reporting on the diagnostic value of FAPI PET/CT in genitourinary malignancies were identified and included. Studies were critically reviewed using a modified version of a tool for quality appraisal of case reports. Study results were summarized using a narrative approach. Results: We included 22 retrospective studies with a cumulative total of 69 patients, focusing on prostate cancer, urothelial carcinoma of the bladder and of the upper urinary tract, renal cell carcinoma, and testicular cancer. FAPI PET/CT was able to visualize both local and metastatic disease, including challenging cases such as prostate-specific membrane antigen (PSMA)-negative prostate cancer. Compared with radiolabeled 18F-FDG and PSMA PET/CT, FAPI PET/CT showed heterogeneous performance. In selected cases, FAPI PET/CT demonstrated superior tumor visualization (i.e., better tumor-to-background ratios and visualization of small tumors or metastatic deposits visible in no other way) over 18F-FDG PET/CT in detecting local or metastatic disease, whereas comparisons with PSMA PET/CT showed both superior and inferior performances. Challenges in FAPI PET/CT arise from physiologic urinary excretion of most FAPI radiotracers, hindering primary-lesion visualization in the bladder and upper urinary tract, despite generally providing high tumor-to-background ratios. Conclusion: The current findings suggest that FAPI PET/CT may hold promise as a future tool to aid clinicians in detecting genitourinary malignancies. Given the substantial heterogeneity among the included studies and the limited number of patients, caution in interpreting these findings is warranted. Subsequent prospective and comparative investigations are anticipated to delve more deeply into this innovative imaging modality and elucidate its role in clinical practice.

The evolution of PET imaging in renal, bladder, upper urinary tract urothelial, testicular and penile carcinoma - Today's impact, tomorrow's potential

INTRODUCTION

The advancement of hybrid PET/CT or PET/MRI imaging for non-prostate genitourinary cancers has not experienced the rapid progress of prostate cancer. Nevertheless, these neoplasms are aggressive and reliable imaging plays a pivotal role in enhancing patients' quality of life and prognosis.

AREAS COVERED

the main evidence regarding [18F]FDG and non-[18F]FDG PET/CT or PET/MRI in non-prostate uro-oncological malignancies are summarized and discussed. Moreover, potential future directions concerning PET imaging in these neoplasms are debated, with the aim to stimulate future research projects covering these fields.

EXPERT OPINION

In Renal Cell Carcinoma (RCC), [18F]FDG PET/CT demonstrates varying efficacy in staging, restaging, and prognostic stratification, but PSMA PET/CT is emerging as a potential game-changer, particularly in advanced, high-grade aggressive clear cell RCC. [18F]FDG PET/CT may see an increased use in N and M-staging of bladder cancer, as well as for detecting recurrence and response to neoadjuvant chemotherapy. Preliminary data regarding [68Ga]-FAPI also looks promising in this context. [18F]FDG PET/MRI could be useful for the T-staging of bladder cancer, while upper tract urothelial carcinoma still lacks of molecular imaging literature reports. In testicular and penile cancer [18F]FDG PET/CT has demonstrated its usefulness in several clinical settings, although experiences with non-[18F]FDG radiotracers are lacking.

Consultation on UTUC II Stockholm 2022: diagnostics, prognostication, and follow-up-where are we today?

PURPOSE

To summarise the current knowledge regarding diagnostics, prognostication and follow-up in upper tract urothelial carcinoma (UTUC).

METHODS

A scoping review combined with expert opinion was applied to provide an overview of the current research field. Based on the published literature and the experts' own experience and opinions, consensus was reached through presentations and discussions at the meeting Consultation on UTUC II in Stockholm 2022.

RESULTS

The strongest prognostic factors in UTUC are tumour grade and stage. They are correlated, and grade is used for indirect staging. The diagnostic examinations should include multiphase computed tomography urography (CTU) with corticomedullary phase, and urethrocystoscopy with cytology. If there is no clear diagnosis for clinical decision-making, ureterorenoscopy (URS) with focal cytology and biopsies should be performed. Both WHO classification systems (1973/1999 and 2004/2016) should be used. Novel biomarker tests are not yet widespread nor recommended for the detection of UTUC. Long-term, regular follow-up, including URS in patients who have had organ-sparing treatment, is important to check for tumour recurrences, intravesical recurrences, metastases and progression of the tumour.

CONCLUSION

Proper diagnostics with correct grading of UTUC are necessary for appropriate treatment decisions. The diagnostics should include CTU with corticomedullary phase, urine or bladder cytology, URS with focal barbotage cytology, and biopsies when needed for proper diagnosis and risk stratification. Regular, long-term follow-ups are fundamental, due to the high rate of recurrence and risk of progression.

Lymph Node Dissection in Upper Tract Urothelial Carcinoma: Current Status and Future Perspectives

PURPOSE OF REVIEW

This narrative review aims to evaluate the role of lymph node dissection (LND) in upper tract urothelial carcinoma (UTUC) and its implications for staging and management outcomes, as well as future perspectives.

RECENT FINDINGS

Multiple studies have demonstrated the limitations of conventional imaging techniques in accurately localizing lymph node metastasis (LNM) in UTUC. While 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18FDG-PET/CT) shows promise for preoperative LNM detection, its specificity is low. Alternative methods such as choline PET/CT and sentinel lymph node detection are under consideration but require further investigation. Additionally, various preoperative factors associated with LNM hold potential for predicting nodal involvement, thereby improving nodal staging and oncologic outcomes of LND. Several surgical approaches, including segmental ureterectomy and robot-assisted nephroureterectomy, provide a possibility for LND, while minimizing morbidity. LND remains the primary nodal staging tool for UTUC, but its therapeutic benefit is still uncertain. Advances in imaging techniques and preoperative risk assessment show promise in improving LNM detection. Further research and multi-center studies are needed to comprehensively assess the advantages and limitations of LND in UTUC, as well as the long-term outcomes of alternative staging and treatment strategies.

Head-to-head comparisons of 68Ga-PSMA-11 and 18F-FDG PET/CT in evaluating patients with upper tract urothelial carcinoma: a prospective pilot study

PURPOSE

To prospectively compare the uptake of 68Ga-prostate specific membrane antigen (68Ga-PSMA)-11 and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in upper tract urothelial carcinoma (UTUC) and investigate the correlation between radiological parameters and pathological features of UTUC.

METHODS

Clinicopathologic and imaging data were collected from 10 UTUC patients who underwent preoperative 68Ga-PSMA-11 and 18F-FDG PET/CT scans. The diagnostic capabilities of both imaging techniques were analyzed and compared in UTUC. Angiogenesis in the malignancies was assessed using Chalkley counting and the expression of folate hydrolase 1 (FOLH1) and glucose transporter 1 (GLUT1) in UTUC were evaluated in the surgical specimens. Double immunofluorescence staining of PSMA and CD34 was used to examine tumor neovascularization. Tracer uptake and expression were compared and explored. Additionally, 10 patients with clear cell renal cell carcinoma (ccRCC) were included for prospective, comparative research.

RESULTS

Ten UTUC patients with 12 malignant lesions and another 10 ccRCC patients were included. 18F-FDG PET/CT demonstrated a more effective detection of UTUC foci compared to 68Ga-PSMA-11 PET/CT (the SUVmax of 18.48 ± 6.73 vs. 4.38 ± 1.45, P < 0.01). Immunohistochemical analysis revealed a statistically significant difference in the expression of PSMA and GLUT1 in UTUC (P = 0.048), with higher pathological grades showing more intense GLUT1 staining than PSMA (75% vs. 12.5%). The Chalkley counting of angiogenesis in ccRCC was significantly higher than that in UTUC (229.34 vs. 71.67), which was proportional to 68Ga-PSMA-11 PET/CT SUVmax (both P < 0.05).

CONCLUSION

18F-FDG PET/CT holds better clinical potential for evaluating UTUC and detecting lymph node metastasis compared to 68Ga-PSMA-11 PET/CT, likely due to the relatively scant expression of FOLH1 in tumor neovascular endothelium while the abundant expression of GLUT1 in malignancy. Furthermore, the lower neovascular density in UTUC should not be overlooked.

Location of Retroperitoneal Lymph Node Metastases in Upper Tract Urothelial Carcinoma: Results from a Prospective Lymph Node Mapping Study

Background

There is limited information on the distribution of retroperitoneal lymph node metastases (LNMs) in upper tract urothelial carcinoma (UTUC).

Objective

To investigate the location of LNMs in UTUC of the renal pelvis or proximal ureter and short-term complications after radical nephroureterectomy (RNU) with lymph node dissection (LND).

Design setting and participants

This was a prospective Nordic multicenter study (four university hospitals, two county hospitals). Patients with clinically suspected locally advanced UTUC (stage >T1) and/or clinical lymph node-positive (cN+) disease were invited to participate. Participants underwent RNU and fractionated retroperitoneal LND using predefined side-specific templates.

Outcome measurements and statistical analysis

The location of LNMs in the LND specimen and retroperitoneal lymph node recurrences during follow-up was recorded. Postoperative complications within 90 d of surgery were ascertained from patient charts. Descriptive statistics were used.

Results and limitations

LNMs were present in the LND specimen in 23/100 patients, and nine of 100 patients experienced a retroperitoneal recurrence. Distribution per side revealed LNMs in the LND specimen in 11/38 (29%) patients with right-sided tumors, for whom the anatomically larger, right-sided template was used, in comparison to 12/62 (19%) patients with left-sided tumors, for whom a more limited template was used. High-grade complications (Clavien grade ≥3) within 90 d of surgery were registered for 13/100 patients. The study is limited in size and not powered to assess survival estimates.

Conclusions

The suggested templates that we prospectively applied for right-sided and left-sided LND in patients with advanced UTUC included the majority of LNMs. High-grade complications directly related to the LND part of the surgery were limited.

Patient summary

This study describes the location of lymph node metastases in patients with cancer in the upper urinary tract who underwent surgery to remove the affected kidney and ureter. The results show that most metastases occur within the template maps for lymph node surgery that we investigated, and that this surgery can be performed with few severe complications.

Imaging in Upper Tract Urothelial Carcinoma: A Review

Medical imaging is a critical tool in the detection, staging, and treatment planning of upper urinary tract urothelial carcinoma (UTUC). This article reviews the strengths and weaknesses of the different imaging techniques and modalities available clinically. This includes multidetector computed tomography (CT), multiparametric magnetic resonance imaging (MRI), ultrasound (US), and positron emission tomography (PET) for the detection, staging, and management of UTUC. In addition, we review the imaging techniques that are being developed and are on the horizon but have not yet made it to clinical practice. Firstly, we review the imaging findings of primary UTUC and the techniques across multiple modalities. We then discuss imaging findings of metastatic disease. Lastly, we describe the role of imaging in the surveillance after resection of primary UTUC based upon current guidelines.

Upper Tract Urothelial Carcinoma: A Rare Malignancy with Distinct Immuno-Genomic Features in the Era of Precision-Based Therapies

Upper tract urothelial carcinoma (UTUC) is a rare malignancy, occurring in 5-10% of patients diagnosed with UC, and involves the renal pelvis, calyces, or ureters. UTUC can be sporadic or hereditary as a clinical manifestation of Lynch syndrome. Therapeutic management of these patients is challenging. Following risk stratification of localized disease, patients with low-grade UTUC may undergo kidney-sparing surgery or radical nephroureterectomy (RNU) and/or chemoablation with mitomycin-c instillation to reduce recurrence. In high-grade disease, RNU followed by adjuvant chemotherapy remains the standard of care. For decades, platinum-based chemotherapy has been the cornerstone of treatment for locally advanced and metastatic disease. The aim of the present review is to summarize recent advances in UTUC's therapeutic management through the lens of its genomic and immune landscape. Accumulating knowledge on the genetic and immune aspects of UTUC tumors has increased our understanding of their underlying biology, supporting a luminal papillary, T-cell depleted contexture and enrichment in fibroblast growth factor receptor (FGFR) expression. These advances have fueled successful clinical testing of several precision-based therapeutic approaches, including immune checkpoint inhibitors (ICIs), the antibody-drug conjugates (ADCs) enfortumab vedotin and sacituzumab govitecan, and agents targeting the FGFR axis such as erdafitinib and other kinase inhibitors, allowing their entry into the therapeutic armamentarium and improving the prognosis of these patients. Not all patients respond to these precision-based targeted therapies; thus, validating and expanding the toolkit of potential biomarkers of response or resistance, including molecular subtypes, FGFR pathway gene alterations, DNA repair gene defects, tumor mutational burden (TMB), circulating tumor DNA (ctDNA), nectin-4, TROP2, and programmed death ligand-1 (PD-L1), are key to maximizing the benefit to these particular subgroups of patients.

European Association of Urology Guidelines on Upper Urinary Tract Urothelial Carcinoma: 2023 Update

CONTEXT

The European Association of Urology (EAU) guidelines panel on upper urinary tract urothelial carcinoma (UTUC) has updated the guidelines to aid clinicians in evidence-based management of UTUC.

OBJECTIVE

To provide an overview of the EAU guidelines on UTUC as an aid to clinicians.

EVIDENCE ACQUISITION

The recommendations provided in these guidelines are based on a review of the literature via a systematic search of the PubMed, Ovid, EMBASE, and Cochrane databases. Data were searched using the following keywords: urinary tract cancer, urothelial carcinomas, renal pelvis, ureter, bladder cancer, chemotherapy, ureteroscopy, nephroureterectomy, neoplasm, (neo)adjuvant treatment, instillation, recurrence, risk factors, metastatic, immunotherapy, and survival. The results were assessed by a panel of experts.

EVIDENCE SYNTHESIS

Even though data are accruing, for many areas there is still insufficient high-level evidence to provide strong recommendations. Patient stratification on the basis of histology and clinical examination (including imaging) and assessment of patients at risk of Lynch syndrome will aid management. Kidney-sparing management should be offered as a primary treatment option to patients with low-risk UTUC and two functional kidneys. In particular, for patients with high-risk or metastatic UTUC, new treatment options have become available. In high-risk UTUC, platinum-based chemotherapy after radical nephroureterectomy, and adjuvant nivolumab for unfit or patients who decline chemotherapy, are options. For metastatic disease, gemcitabine/carboplatin chemotherapy is recommended as first-line treatment for cisplatin-ineligible patients. Patients with PD-1/PD-L1-positive tumours should be offered a checkpoint inhibitor (pembrolizumab or atezolizumab).

CONCLUSIONS

These guidelines contain information on the management of individual patients according to the current best evidence. Urologists should take into account the specific clinical characteristics of each patient when determining the optimal treatment regimen according to the risk stratification of these tumours.

PATIENT SUMMARY

Cancer of the upper urinary tract is rare, but because 60% of these tumours are invasive at diagnosis, timely and appropriate diagnosis is most important. A number of known risk factors exist.

Upper Tract Urinary Carcinoma: A Unique Immuno-Molecular Entity and a Clinical Challenge in the Current Therapeutic Scenario

Urothelial carcinoma (UC) is the most frequent malignancy of the urinary tract, which consists of bladder cancer (BC) for 90%, while 5% to 10%, of urinary tract UC (UTUC). BC and UTUC are characterized by distinct phenotypical and genotypical features as well as specific gene- and protein- expression profiles, which result in a diverse natural history of the tumor. With respect to BC, UTUC tends to be diagnosed in a later stage and displays poorer clinical outcome. In the present review, we seek to highlight the individuality of UTUC from a biological, immunological, genetic-molecular, and clinical standpoint, also reporting the most recent evidence on UTUC treatment. In this regard, while the role of surgery in nonmetastatic UTUC is undebated, solid data on adjuvant or neoadjuvant chemotherapy are still an unmet need, not permitting a definite paradigm shift in the standard treatment. In advanced setting, evidence is mainly based on BC literature and retrospective studies and confirms platinum-based combination regimens as bedrock of first-line treatment. Recently, immunotherapy and target therapy are gaining a foothold in the treatment of metastatic disease, with pembrolizumab and atezolizumab showing encouraging results in combination with chemotherapy as a first-line strategy. Moreover, atezolizumab performed well as a maintenance treatment, while pembrolizumab as a single agent achieved promising outcomes in second-line setting. Regarding the target therapy, erdafitinib, a fibroblast growth factor receptor inhibitor, and enfortumab vedotin, an antibody-drug conjugate, proved to have a strong antitumor property, likely due to the distinctive immune-genetic background of UTUC. In this context, great efforts have been addressed to uncover the biological, immunological, and clinical grounds in UTUC patients in order to achieve a personalized treatment.

Robot-assisted nephroureterectomy for upper tract urothelial carcinoma-feasibility and complications: a single center experience

BACKGROUND

Robot-assisted nephroureterectomy (RANU) is the primary treatment for upper tract urothelial carcinoma (UTUC) at our hospital for patients with clinical stage less than T2, and for patients with invasive tumours, but unfit for major surgery.

OBJECTIVE

To assess peri-operative conditions and outcomes of RANU at our unit, and to evaluate the safety of the procedure.

METHODS

The medical records of all 166 patients undergoing RANU for suspected UTUC and followed for more than three months in a large university hospital in Sweden were reviewed retrospectively. After the exclusion of twenty patients because of previous cystectomy, simultaneous surgical procedure, or other tumour types than UTUC in the pathological report, 146 patients remained for the analyses. The primary endpoint was complication rate according to Clavien-Dindo at 90 days. Secondary endpoints were perioperative bleeding, violation of oncological surgical principles, hospital stay, and re-admission within 90 days.

RESULTS

The median age was 75 [(Inter Quartile Range) IQR 70-80] years and 57% of the patients had an ASA score above 2. According to Clavien-Dindo, one patient had a grade 3 complication, and no patient had a grade 4-5 complication. The median blood loss was 50 (IQR 20-100) ml and the median hospital stay was 6 (IQR 5-7) days. Twelve patients were re-admitted to the hospital within 90 days (eight with urinary tract infection/haematuria, one with hematoma, and three with other diseases).

CONCLUSION

Robot-assisted nephroureterectomy is a safe procedure for patients with upper tract urothelial carcinoma, with a low risk of major surgical complications.

Lymph Node Dissection During Radical Nephro-Ureterectomy for Upper Tract Urothelial Carcinoma: A Review

Although lymphonodal dissection is well-accepted for muscle-invasive bladder cancer management, its role is still debated during radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC). The aim of this study was to summarize the current knowledge concerning the indication, anatomical template, prognostic, and therapeutic roles of lymph node dissection (LND) performed at the time of RNU. Quality control markers, such as the number of lymph nodes (LN) removed, lymph node density, and safety of the different surgical approaches, were assessed. We performed a narrative review using the PubMed and ClinicalTrials.gov databases. We identified and analyzed articles based on the practice and the role of lymph node dissection for non-metastatic UTUC. There are no clear guidelines regarding the indication of LND for UTUC, but aggressive tumors may beneficiate from lymphadenectomy since lymph node invasion is a clear independent poor prognostic factor, allowing for adjuvant treatments. It seems that an extended lymphadenectomy may provide therapeutic advantages as a higher number of nodes removed may be related to the removal of undetected LNs micrometastases and a subsequent improvement in recurrence rate and cancer-specific survival. Clear anatomical templates are thus needed based on the location and the laterality of the primary tumor.

Non-Invasive Biomarkers in the Diagnosis of Upper Urinary Tract Urothelial Carcinoma-A Systematic Review

Beyond laboratory, imaging and endoscopic procedures, new diagnostic tools are increasingly being sought for the diagnosis of upper urinary tract urothelial carcinoma (UTUC), especially those that are non-invasive. In this systematic review, we aimed to determine the effectiveness of non-invasive tests in the diagnosis of UTUC. PubMed and Embase electronic databases were searched to identify studies assessing effectiveness of non-invasive tests in the primary diagnosis of UTUC. The study protocol was registered with PROSPERO (CRD42020216480). Among 10,084 screened publications, 25 were eligible and included in the analysis. Most of them were conducted on small samples of patients and the control groups were heterogenous. The test used in the largest number of studies was voided urinary cytology, which has poor sensitivity (11-71.1%) with favorable specificity (54-100%). Fluorescence in situ hybridization in diagnostic cytology showed higher sensitivity (35-85.7%) with equally good specificity (80-100%). There were also studies on the use of tests known to diagnose bladder cancer such as NMP22, uCYT or BTA test. Other urine or blood tests have been the subject of only isolated studies, with varying results. To conclude, currently there is a lack of high-quality data that could confirm good effectiveness of non-invasive tests used in the diagnosis of UTUC.

Prospective Clinical Trial of the Oncologic Outcomes and Safety of Extraperitoneal Laparoscopic Extended Retroperitoneal Lymph Node Dissection at Time of Nephroureterectomy for Upper Tract Urothelial Carcinoma

Purpose

To determine the safety and feasibility of extraperitoneal laparoscopic extended lymph node dissection (LND) at the time of extraperitoneal laparoscopic radical nephroureterectomy (RNU).

Materials and Methods

Between May 2018 and March 2019, 39 patients with upper tract urothelial carcinoma (UTUC) received extraperitoneal laparoscopic RNU and concomitant extraperitoneal laparoscopic extended LND. All patients were followed for at least 90 days. Perioperative and pathological data including nodal status and perioperative complications were collected.

Results

Among all 39 patients, 12 patients had pT1, 6 had pT2, 20 had pT3 disease, and 1 had T4 disease. The median (range) lymph node count was 10 (5–22), with 8 patients having pathologically proven lymph node metastasis. The median (range) operating time was 225 (165–430) min, and the median estimated blood loss was 200 (60–800) ml. The median postoperative hemoglobin loss was 1.6 (0–4.2) g/dl. The median (range) postoperative hospital stays were 6 (3–26) days. Overall, 7 patients experienced minor (Clavien Grade I–II) postoperative complications with five patients having Clavien Grade I complications and two patients having Clavien Grade II complications. No major complication (Clavien grade III–IV) occurred. With a median follow-up of 38 months, a total of 8 patients (20.5%) developed local or distant recurrence and no regional LNs where extended LND were performed had recurrence.

Conclusions

The present prospective study demonstrated that extraperitoneal laparoscopic extended LND during extraperitoneal laparoscopic RNU for UTUC is a feasible and safe procedure which provides minimal invasion, rapid recovery, and potentially lower risk of regional LN recurrence. Larger prospective clinical trials with survival endpoints are needed to further determine its potential therapeutic benefits.

Trial Registration

ClinicalTrials.gov identifier NCT 03544437 www.clinicaltrials.gov

PET/CT in Bladder Cancer: An Update

In the urinary tract, bladder cancer is the most common malignancy. It is a heterogenous cancer type with approximately 30% presenting as muscle invasive bladder cancer with a high risk of metastatic spread associated with risk of death from distant metastases. The other 70% of bladder cancer patients present with superficial tumors with tendency of recurrence but in general not life-threatening. Like in other malignancies, accurate and precise staging of bladder cancer is one of the mainstays at the time of diagnosis to select the optimal treatment for each patient. The detection of metastatic spread is of utmost importance for selection of treatment strategy. Hybrid imaging med with FDG PET/CT is widely used in the clinical management of a variety of malignancies. FDG PET/CT is increasingly used for primary staging of muscle invasive bladder cancer and for detection of recurrence after radical cystectomy. Few studies have used FDG PET/CT for response evaluation of neoadjuvant, induction chemotherapy or immunotherapy. Furthermore, small studies have tested non-FDG PET agents with little or no urinary excretions of the tracer. This review provides an update on PET/CT in bladder cancer.

[Imaging of oligometastatic disease in selected urologic cancers]

BACKGROUND

Local treatment of the primary or metastatic sites in urologic malignancies is promising when compared to systemic therapy alone, leading to the definition of a potentially curative oligometastatic state.

OBJECTIVES

Comparison of imaging modalities regarding local and metastatic tumor sites in urologic cancers.

METHODS

Review of comparative trials addressing quality criteria of imaging modalities.

RESULTS

Depending on primary tumor and metastatic site, conventional imaging modalities such as computer tomography (CT) and bone scintigraphy still represent the standard of care in Germany. Due to superior quality criteria, hybrid-imaging techniques were widely adopted for oncological staging and particular due to the new PSMA-ligand (PSMA-PET/CT) in prostate cancer imaging. The development of new radioisotopes as well as their clinical application remains a focus of current research.

CONCLUSIONS

High-quality diagnostic imaging modalities lay the groundwork for a precise definition of an oligometastatic state. By enabling treatment of the entire tumor burden, a delay of systemic therapy, longer progression-free survival, or even curative treatment may become achievable.

Discordance Between Clinical and Pathological Staging and Grading in Upper Tract Urothelial Carcinoma

INTRODUCTION

This study aimed to evaluate the concordance in tumor stage and grade between ureteroscopic (URS) biopsy and radical nephroureterectomy (RNU) in patients with upper tract urothelial carcinoma (UTUC).

PATIENTS AND METHODS

Records of 1,214 UTUC patients who had undergone URS biopsy followed by RNU were included. Univariable and multivariable logistic regression analyses were performed to identify factors contributing to the pathological upstaging.

RESULTS

The concordance between URS biopsy-based clinical and RNU pathological staging was 34.5%. Clinical understaging occurred in 59.5% patients. Upstaging to muscle-invasive disease occurred in 240 (41.7%) of 575 patients diagnosed with ≤cT1 disease. Of those diagnosed with muscle-invasive disease on final pathology, 89.6% had been clinically diagnosed with ≤cT1 disease. In the univariable analyses, computed tomography urography (CTU)-based invasion, ureter location, hydronephrosis, high-grade cytology, high-grade biopsy, sessile architecture, age, and women sex were significantly associated with pathological upstaging (P < .05). In the multivariable analyses, CTU-based invasion and hydronephrosis remained associated with pathological upstaging (P < .05). URS biopsy-based clinical and pathological gradings were concordant in 634 (54.2%) patients. Clinical undergrading occurred in 496 (42.4%) patients.

CONCLUSIONS

Clinical understaging/undergrading and upstaging to muscle-invasive disease occurred in a high proportion of UTUC patients undergoing RNU. Despite the inherent selection bias, these data underline the challenges of accurate UTUC staging and grading. In daily clinical practice, URS biopsy and CTU offer the most accurate preoperative information albeit with limited predictive value when used alone. These findings should be considered when utilizing preoperative, risk-adapted strategies.

Diagnostic values of F-18 FDG PET or PET/CT, CT, and US for Preoperative Lymph Node Staging in Thyroid Cancer: A Network Meta-Analysis

OBJECTIVE

This study compared the diagnostic performance of three different imaging modalities for preoperative lymph node (LN) staging in thyroid cancer patients, using a network meta-analysis (NMA).

METHODS

PubMed and Embase were searched to identify studies evaluating the performance of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET or PET/CT), computed tomography (CT), and ultrasonography (US) for preoperative LN staging in thyroid cancer patients. The NMA included both patient- and lesion-based analyses. The surface under the cumulative ranking curve (SUCRA) values was used to decide on the most effective diagnostic method.

RESULTS

A total of 3,571 patients from 19 direct comparison studies using three different imaging modalities for preoperative LN staging in thyroid cancer patients were included. US showed the highest SUCRA values for positive predictive values (PPV), negative predictive values (NPV), and accuracy in detection of all cervical LN metastasis. F-18 FDG PET or PET/CT and US showed the highest SUCRA values for PPV and sensitivity, respectively, for central LN, and the highest SUCRA value of specificity and sensitivity, respectively, for lateral LN.

CONCLUSION

The results from this NMA indicate that F-18 FDG PET or PET/CT, CT, and US have complementary diagnostic roles for preoperative staging in thyroid cancer patients.

ADVANCES IN KNOWLEDGE

Using NMA, we comprehensively compared the different diagnostic values and limitations of F-18 FDG PET or PET/CT, CT, and US for the preoperative LN staging in thyroid cancer patients.

Performance of fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography imaging for lymph node staging in bladder and upper tract urothelial carcinoma: a systematic review

Objective: To evaluate the current literature on the accuracy of fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (FDG PET-CT) for lymph node (LN) staging in urothelial carcinoma (UC), as robust evidence on the value of this technology in UC is still lacking.

Methods: The Medical Literature Analysis and Retrieval System Online (MEDLINE)/PubMed, Cochrane Library, and Scopus databases were searched for eligible studies. We included all original studies evaluating FDG PET-CT in bladder or upper tract UC. The search results were restricted to the English language, and included prospective and retrospective studies without time restriction. We included only studies reporting the sensitivity and specificity of FDG PET-CT in detecting UC LN metastases.

Results: We identified 23 articles meeting our inclusion criteria. In the preoperative setting, the sensitivity of FDG PET-CT for detecting LN metastases in patients with bladder cancer was widely variable ranging from 23% to 89%; the specificity ranged from 81% to 100%; and the overall accuracy ranged from 65% to 89%. During bladder cancer monitoring the sensitivity for detecting LN metastases ranged from 75% to 92% and the specificity ranged from 60% to 92%. The sensitivity for LN staging in upper tract UC ranged between 82% and 95%, with a specificity of 84–91%.

Conclusion: Despite the inconsistencies in sensitivity between the reports, FDG PET-CT seems to have a high specificity for LN staging in patients with UC. Future prospective, well-designed studies are necessary to evaluate the role of FDG PET-CT in UC management.

Abbreviations: FDG: fluoro-2-deoxy-D-glucose; LN: lymph node; PET: positron emission tomography; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-analyses; PSMA: prostate-specific membrane antigen; (N)(P)PV: (negative) (positive) predictive value; QUADAS-2: Quality Assessment of Diagnostic Accuracy Studies-2; SUV_max: maximum standard uptake value; (UT)UC: (upper urinary tract) urothelial carcinoma

Diagnostic challenges and treatment strategies in the management of upper-tract urothelial carcinoma

Upper-tract urothelial carcinoma (UTUC) is a rare disease, posing many challenges for the treating physician due to the lack of strong evidence-based recommendations. However, novel molecular discoveries and a better understanding of the clinical behavior of the disease lead to a continuous evolution of therapeutic landscape in UTUC. The aim of the review is to provide a comprehensive update of the current diagnostic modalities and treatment strategies in UTUC with a special focus on recent developments and challenges. A comprehensive literature search including relevant articles up to August 2020 was performed using the MEDLINE/PubMed database. Despite several technological improvements, accurate staging and outcome prediction remain major challenges and hamper appropriate risk stratification. Kidney-sparing surgery can be offered in low risk UTUC; however, physician and patient must be aware of the high rate of recurrence and risk of progression due to tumor biology and understaging. The value and efficacy of intracavitary therapy in patients with UTUC remains unclear due to the lack of high-quality data. In high-risk diseases, radical nephroureterectomy with bladder cuff excision and template lymph node dissection is the standard of care. Perioperative systemic chemotherapy is today accepted as a novel standard for advanced cancers. In metastatic or unresectable disease, the therapeutic landscape is rapidly changing due to several novel agents, such as checkpoint inhibitors. While several diagnostic and treatment challenges remain, progress in endoscopic technology and molecular knowledge have ushered a new age in personalized management of UTUC. Novel accurate molecular and imaging biomarkers are, however, still needed to guide decision making as tissue acquisition remains suboptimal. Next generation sequencing and novel agents are promising to rapidly improve patient outcomes.