Increased Utilization of Positron Emission Tomography/Computed Tomography (PET/CT) Imaging and Its Economic Impact for Patients Diagnosed With Bladder Cancer

The Financial Burden of Localized and Metastatic Bladder Cancer

BACKGROUND AND OBJECTIVE

Bladder cancer (BCa) imposes a substantial economic burden on health care systems and patients. Understanding these financial implications is crucial for effective resource allocation and optimization of treatment cost effectiveness. Here, we aim to systematically review and analyze the financial burden of BCa from the health care and patient perspectives.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA)-compliant systematic review was conducted, searching PubMed/Medline, Embase, and public sources for studies evaluating the financial impact of BCa, encompassing costs, cost effectiveness, and financial toxicity (FT).

KEY FINDINGS AND LIMITATIONS

Non-muscle-invasive BCa (NMIBC) incurs significant costs for surveillance and treatment, with costs exceeding $200 000 after 5 yr for high-risk NMIBC patients progressing after bacillus Calmette-Guerin (BCG) treatment (including inpatient, outpatient, and physician service expenses). Muscle-invasive BCa generates substantial costs from radical cystectomy (RC) and neoadjuvant chemotherapy, averaging $30 000-40 000 from surgical costs of RC, with additional expenses in case of complications. Trimodal therapy has higher costs (1-yr management cost >$200 000) than RC because of higher outpatient, radiology, and medication costs. Metastatic BCa incurs the highest financial burden, with systemic therapy costs ranging from $40 000 to over $100 000 per five-cycle course, increasing further with combination therapies (ie, enfortumab vedotin and pembrolizumab), treatment-related toxicity, and supportive care. FT is particularly prevalent among younger, less educated, and minority populations.

CONCLUSIONS AND CLINICAL IMPLICATIONS

BCa treatment, particularly in advanced stages, imposes a substantial economic burden. Innovations in care, while improving oncologic outcomes, necessitate detailed cost-effectiveness assessments. Addressing these economic challenges is essential for optimizing BCa management, targeting patients at a higher risk of FT, and improving patient quality of life.

Use of F-18 FDG PET/CT Through Delayed Diuretic Imaging for Preoperative Evaluation of Upper Urinary Tract-Occupying Lesions

Purpose

To evaluate the value of F-18 FDG PET/CT in the differentiation of malignant and benign upper urinary tract-occupying lesions.

Patients and Methods

64 patients with upper urinary tract-occupying lesions underwent F-18 FDG PET/CT at RenJi Hospital from January 2015 to February 2019 in this retrospective study. Of the 64 patients, 50 patients received nephroureterectomy or partial ureterectomy; 14 patients received ureteroscopy and biopsy. The comparisons of PET/CT parameters and clinical characteristics between malignant and benign upper urinary tract-occupying lesions were investigated.

Results

Of the 64 patients, 49 were found to have malignant tumors. Receiver operating characteristic analysis determined the lesion SUVmax value of 6.75 as the threshold for predicting malignant tumors. There were significant associations between malignant and benign upper urinary tract-occupying lesions and SUVmax of lesion (P<0.001), lesion size (P<0.001), and patient age (P=0.011). Multivariate analysis showed that SUVmax of lesion (P=0.042) and patient age (P=0.009) as independent predictors for differentiation of malignant from benign upper urinary tract-occupying lesions. There was a significant difference in tumor size between the positive (SUVmax >6.75) and negative (SUVmax ≤6.75) PET groups in 38 of the 49 patients with malignant tumors.

Conclusion

The SUVmax of lesion and patient age is associated with the nature of upper urinary tract-occupying lesions. F-18 FDG PET/CT may be useful to distinguish between malignant and benign upper urinary tract-occupying lesions and determine a suitable therapeutic strategy.

99mTc-Methionine Gold Nanoparticles as a Promising Biomaterial for Enhanced Tumor Imaging

Methionine-gold nanoparticles (MGNs) was synthesized by conjugating methionine via dithiocarbamate linkage to gold nanoparticles (GNPs), prepared simultaneously by one pot modified Burst method. Formation of MGNs was confirmed by UV-visible spectroscopy and appearance of new IR bands in the range of 934 cm^-1 to 1086 cm^-1 and shifting of N-C,S-S and S-C-S stretching, confirms the involvement of '-S-C-S-' group of methionine dithiocarbamate with GNPs. The presence of Au in MGNs was confirmed by EDXA spectrum, whereas TEM, SAED and XRD revealed that MGNs are nanocrystalline (~13 nm) and have face-centered cubic structure. MGNs was labeled with ^99mTc (TMGNs) with radiolabeling efficiency greater than 99% using 300 μg of stannous chloride, pH 7 and 90.6 MBq of ^99mTcO₄. The stability data showed that the conjugate will remain infrangible in systemic circulation and in acidic microenvironment of tumor. The blood kinetic profile of TMGN in rabbits and biodistribution studies in EAT tumor bearing balb/c mice showed longer in vivo circulation and slow clearance compared to radiolabeled methionine (TM). TMGN demonstrated nearly three-fold higher tumor accumulation (3.9 ± 0.35% ID/g), 2-fold lower tumor saturation dose (1.0 μg/kg) and higher tumor retention compared with TM. Data showed that the TMGN tumor: blood ratio (1.05) is nearly 2.5-fold higher than TM (0.44), whereas TMGN tumor: muscle ratio (97.5) is nearly 8-fold higher than TM (11.6). In conclusion, TMGN showed excellent tumor targeting and has promising prospects as a SPECT-radiopharmaceutical for imaging tumors.

The Role of 18F-FDG PET/CT in Guiding Precision Medicine for Invasive Bladder Carcinoma

Bladder cancer (BC) is the 10th most common cancer worldwide. Approximately one quarter of patients with BC have muscle-invasive disease (MIBC). Muscle-invasive disease carries a poor prognosis and choosing the optimal treatment option is critical to improve patients’ outcomes. Ongoing research supports the role of 2-deoxy-2-(18F)fluoro-D-glucose positron emission tomography (18F-FDG PET) in guiding patient-specific management decisions throughout the course of MIBC. As an imaging modality, 18F-FDG PET is acquired simultaneously with either computed tomography (CT) or MRI to offer a hybrid approach combining anatomical and metabolic information that complement each other. At initial staging, 18F-FDG PET/CT enhances the detection of extravesical disease, particularly in patients classified as oligometastatic by conventional imaging. 18F-FDG PET/CT has value in monitoring response to neoadjuvant and systemic chemotherapy, as well as in localizing relapse after treatment. In the new era of immunotherapy, 18F-FDG PET/CT may also be useful to monitor treatment efficacy as well as to detect immune-related adverse events. With the advent of artificial intelligence techniques such as radiomics and deep learning, these hybrid medical images can be mined for quantitative data, providing incremental value over current standard-of-care clinical and biological data. This approach has the potential to produce a major paradigm shift toward data-driven precision medicine with the ultimate goal of personalized medicine. In this review, we highlight current literature reporting the role of 18F-FDG PET in supporting personalized management decisions for patients with MIBC. Specific topics reviewed include the incremental value of 18F-FDG PET in prognostication, pre-operative planning, response assessment, prediction of recurrence, and diagnosing drug toxicity.

The Role of Imaging in Bladder Cancer Diagnosis and Staging

Bladder cancer (BC) is the most common cancer of the urinary tract in the United States. Imaging plays a significant role in the management of patients with BC, including the locoregional staging and evaluation for distant metastatic disease, which cannot be assessed at the time of cystoscopy and biopsy/resection. We aim to review the current role of cross-sectional and molecular imaging modalities for the staging and restaging of BC and the potential advantages and limitations of each imaging modality. CT is the most widely available and frequently utilized imaging modality for BC and demonstrates good performance for the detection of nodal and visceral metastatic disease. MRI offers potential value for the locoregional staging and evaluation of muscular invasion of BC, which is critically important for prognostication and treatment decision-making. FDG-PET/MRI is a novel hybrid imaging modality combining the advantages of both MRI and FDG-PET/CT in a single-setting comprehensive staging examination and may represent the future of BC imaging evaluation.

Utility of Routine Preoperative 18F-Fluorodeoxyglucose Positron Emission Tomography/Computerized Tomography in Identifying Pathological Lymph Node Metastases at Radical Cystectomy

PURPOSE

We determined the diagnostic performance of 18F-FDG (fluorodeoxyglucose) positron emission tomography/computerized tomography for detecting nodal metastases in patients with muscle invasive urothelial bladder cancer before radical cystectomy.

MATERIALS AND METHODS

Preoperative 18F-FDG positron emission tomography/computerized tomography scans (208) were retrospectively reviewed. Scans were routinely performed in 185 patients with muscle invasive urothelial bladder cancer between August 2012 and February 2017, all of whom underwent radical cystectomy and pelvic lymph node dissection. Analyses were stratified by clinical node involvement and chemotherapy status. The diagnostic performance of 18F-FDG positron emission tomography/computerized tomography was assessed according to sensitivity, specificity, positive predictive value and negative predictive value.

RESULTS

Lymph node metastases at time of pelvic lymph node dissection were present in 21.8% of those without suspicious nodes on computerized tomography (clinically node negative) and 52.6% of those with suspicious nodes on computerized tomography (clinically node positive). Median metastatic focus size was 5 mm. In clinically node negative cases 18F-FDG positron emission tomography/computerized tomography rarely detected nodal metastases (sensitivity 7% to 23%). In clinically node positive cases negative 18F-FDG positron emission tomography/computerized tomography was useful in ruling out lymph node metastases (sensitivity 92% to 100%). This study was limited by its mixed population and focus on pelvic nodal metastases only.

CONCLUSIONS

18F-FDG positron emission tomography/computerized tomography appears to be most useful for better characterization of enlarged nodes identified by computerized tomography. Routine preoperative 18F-FDG positron emission tomography/computerized tomography has limited utility in clinically node negative cases.

Delayed post-diuretic 18F-FDG PET/CT for preoperative evaluation of renal pelvic cancer

Background: Application of ¹⁸F^-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) in urological oncology was relatively slowly due to the urinary elimination of ¹⁸F-FDG. We investigated whether delayed post-diuretic ¹⁸F-FDG PET/CT could be used for diagnosing renal pelvic cancer.

Methods: 51 patients were included who underwent delayed post-diuretic ¹⁸F-FDG PET/CT for detecting renal pelvic space-occupying lesions. The comparations of delayed PET/CT parameters and clinical characteristics between renal pelvic cancer and benign polyp were investigated.

Results: Among the 51 patients, 47 were found to have renal pelvic urothelial carcinoma, and 4 had benign polyp. ROC analysis identified the lesion maximum standardized uptake value (SUVmax) of 6.2 as the optimal cut-off value to distinguish from renal pelvic urothelial carcinoma to benign polyp. With the SUVmax cut-off of 6.2, the sensitivity, and specificity for predicting of renal pelvic urothelial carcinoma were 91.5% (43/47), and 100% (4/4). We also found a significant difference in tumor size between the positive (SUVmax > 6.2) and negative (SUVmax ≤ 6.2) PET groups in renal pelvic cancers. In patients with tumor size < 1.1 cm, the probability of being in the negative PET group was 75%. In such patients, a substantial proportion of renal pelvic cancer demonstrated negative SUVmax similar to that in patients with benign polyp.

Conclusion: Delayed ¹⁸F-FDG PET/CT could be used for differentiating renal pelvic cancer from benign polyp. In patients with small tumor size, renal pelvic cancer may present low ¹⁸F-FDG uptake, mimicking the metabolic phenotypes of patients with benign polyp.