Staging 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Changes Treatment Recommendation in Invasive Bladder Cancer

The optimal number of induction chemotherapy cycles in clinically lymph node-positive bladder cancer

OBJECTIVE

To investigate the optimal number of induction chemotherapy cycles needed to achieve a pathological response in patients with clinically lymph node-positive (cN+) bladder cancer (BCa) who received three or four cycles of induction chemotherapy followed by consolidative radical cystectomy (RC) with pelvic lymph node dissection.

PATIENTS AND METHODS

We included 388 patients who received three or four cycles of cisplatin/gemcitabine or (dose-dense) methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC), followed by consolidative RC for cTanyN1-3M0 BCa. We compared pathological complete (pCR = ypT0N0) and objective response (pOR = yp ≤T1N0) between treatment groups. Predictors of pCR and/or pOR were assessed using uni- and multivariable logistic regression analysis. The secondary endpoints were overall (OS) and cancer-specific survival (CSS). We evaluated the association between the number of induction chemotherapy cycles administered and survival outcomes on multivariable Cox regression.

RESULTS

Overall, 101 and 287 patients received three or four cycles of induction chemotherapy, respectively. Of these, 72 (19%) and 128 (33%) achieved pCR and pOR response, respectively. The pCR (20%, 18%) and pOR (40%, 31%) rates did not differ significantly between patients receiving three or four cycles (P > 0.05). The number of cycles was not associated with pCR or pOR on multivariable logistic regression analyses. The 2-year OS estimates were 63% (95% confidence interval [CI] 0.53-0.74) and 63% (95% CI 0.58-0.7) for patients receiving three or four cycles, respectively. Receiving three vs four cycles was not associated with OS and CSS on uni- or multivariable Cox regression analyses.

CONCLUSION

Pathological response and survival outcomes did not differ between administering three or four induction chemotherapy cycles in patients with cN+ BCa. A fewer cycles (minimum three) may be oncologically sufficient in patients with cN+ BCa, while decreasing the wait for definitive local therapy in those patients who end up without a response to chemotherapy. This warrants further validation.

Clinical Upstaging After Neoadjuvant Chemotherapy Impacting Eligibility for Vaginal-sparing Cystectomy: Identifying Bladder Cancer Patients Who May Benefit From Interim Imaging

OBJECTIVE

Limited data exist on the frequency with which clinical progression during neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) impacts eligibility for a vaginal-sparing surgical approach or on the utility of interim imaging assessment. We sought to evaluate the incidence of clinical upstaging following NAC that would render a patient ineligible for a vaginal-sparing cystectomy.

METHODS

Eighty-nine female patients with non-metastatic MIBC treated with NAC and radical cystectomy (RC) (2012-2023) were retrospectively reviewed. Tumor location(s) was determined from transurethral resection of bladder tumor operative reports. Pre- and post-NAC clinical staging was determined from imaging. Outcomes of interest included clinical upstaging and upstaging to vaginal invasion after NAC.

RESULTS

75/89 patients had pre- and post-NAC imaging. Fifty-five had no change in clinical staging, 6 patients were upstaged (4 cT2→cT3, 2 cT3→cT4), and 14 patients were downstaged (13 cT3→cT2, 1 cT4→cT2). Of the 75 patients with pre- and post-NAC imaging, 39 had trigone tumors. Of these, 28 had no change in clinical staging, 2 were upstaged (1 cT2→cT3, 1 cT3→cT4) and 9 were downstaged (8 cT3→cT2, 1 cT4→cT2). Overall, 6/75 (8%) of patients demonstrated clinical upstaging after NAC. 2/39 (5%) of patients with trigone tumors clinically progressed after NAC and both had vaginal invasion (pT4) on final pathology.

CONCLUSION

Although clinical upstaging after NAC was infrequent, 5% of patients with trigonal MIBC were rendered ineligible for vaginal-sparing cystectomy following NAC due to progression. Interim imaging assessment may identify non-responders and preserve eligibility for vaginal-sparing RC.

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.

Management of patients with muscle-invasive bladder cancer with clinical evidence of pelvic lymph node metastases

Identification of clinically positive pelvic lymph node metastases (cN+) in patients with muscle-invasive bladder cancer is currently challenging, as the diagnostic accuracy of available imaging modalities is limited. Conventional CT is still considered the gold-standard approach to diagnose lymph node metastases in these patients. The development of innovative diagnostic methods including radiomics, artificial intelligence-based models and molecular biomarkers might offer new perspectives for the diagnosis of cN+ disease. With regard to the treatment of these patients, multimodal strategies are likely to provide the best oncological outcomes, especially using induction chemotherapy followed by radical cystectomy and pelvic lymph node dissection in responders to chemotherapy. Additionally, the use of adjuvant nivolumab has been shown to decrease the risk of recurrence in patients who still harbour ypT2-T4a and/or ypN+ disease after surgery. Alternatively, the use of avelumab maintenance therapy can be offered to patients with unresectable cN+ tumours who have at least stable disease after induction chemotherapy alone. Lastly, patients with cN+ tumours who are not responding to induction chemotherapy are potential candidates for receiving second-line treatment with pembrolizumab.

Impact of the extent of lymph node dissection on survival outcomes in clinically lymph node-positive bladder cancer

OBJECTIVE

To determine the oncological impact of extended pelvic lymph node dissection (ePLND) vs standard PLND (sPLND) during radical cystectomy (RC) in clinically lymph node-positive (cN+) bladder cancer (BCa).

PATIENTS AND METHODS

In this retrospective, multicentre study we included 969 patients who underwent RC with sPLND (internal/external iliac and obturator lymph nodes) or ePLND (sPLND plus common iliac and presacral nodes) with or without platin-based peri-operative chemotherapy for cTany N1-3 M0 BCa between 1991 and 2022. We assessed the impact of ePLND on recurrence-free survival (RFS) and the distribution of recurrences (locoregional and distant recurrences). The secondary endpoint was overall survival (OS). We performed propensity-score matching using covariates associated with the extent of PLND in univariable logistic regression analysis. The association of the extent of PLND with RFS and OS was investigated using Cox regression models.

RESULTS

Of 969 cN+ patients, 510 were 1:1 matched on propensity scores. The median (interquartile range [IQR]) time to recurrence was 8 (4-16) months, and median (IQR) follow-up of alive patients was 30 (13-51) months. Disease recurrence was observed in 104 patients in the ePLND and 107 in the sPLND group. Of these, 136 (27%), 47 (9.2%) and 19 patients (3.7%) experienced distant, locoregional, or both distant and locoregional disease recurrence, respectively. When stratified by the extent of PLND, we did not find a difference in recurrence patterns (P > 0.05). ePLND improved neither RFS (hazard ratio [HR] 0.91, 95% confidence interval [CI] 0.70-1.19; P = 0.5) nor OS (HR 0.78, 95% CI 0.60-1.01; P = 0.06) compared to sPLND. Stratification by induction chemotherapy did not change outcomes.

CONCLUSION

Performing an ePLND at the time of RC in cN+ patients improved neither RFS nor OS compared to sPLND, regardless of induction chemotherapy status. Pretreatment risk stratification is paramount to identify ideal candidates for RC with ePLND as part of a multimodal treatment approach.

European Association of Urology Guidelines on Muscle-invasive and Metastatic Bladder Cancer: Summary of the 2023 Guidelines

CONTEXT

We present an overview of the updated 2023 European Association of Urology (EAU) guidelines for muscle-invasive and metastatic bladder cancer (MMIBC).

OBJECTIVE

To provide practical evidence-based recommendations and consensus statements on the clinical management of MMIBC with a focus on diagnosis and treatment.

EVIDENCE ACQUISITION

A broad and comprehensive scoping exercise covering all areas of the MMIBC guidelines has been performed annually since 2017. Searches cover the Medline, EMBASE, and Cochrane Libraries databases for yearly guideline updates. A level of evidence and strength of recommendation are assigned. The evidence cutoff date for the 2023 MIBC guidelines was May 4, 2022.

EVIDENCE SYNTHESIS

Patients should be counselled regarding risk factors for bladder cancer. Pathologists should describe tumour and lymph nodes in detail, including the presence of histological subtypes. The importance of the presence or absence of urothelial carcinoma (UC) in the prostatic urethra is emphasised. Magnetic resonance imaging (MRI) of the bladder is superior to computed tomography (CT) for disease staging, specifically in differentiating T1 from T2 disease, and may lead to a change in treatment approach in patients at high risk of an invasive tumour. Imaging of the upper urinary tract, lymph nodes, and distant metastasis is performed with CT or MRI; the additional value of flurodeoxyglucose positron emission tomography/CT still needs to be determined. Frail and comorbid patients should be evaluated by a multidisciplinary team. Postoperative histology remains the most important prognostic variable, while circulating tumour DNA appears to be an interesting predictive marker. Neoadjuvant systemic therapy remains cisplatin-based. In motivated and selected women and men, sexual organ-preserving cystectomy results in better functional outcomes without compromising oncological outcomes. Robotic and open cystectomy have comparable outcomes and should be combined with (extended) lymph node dissection. The diversion type is an individual choice after taking patient and tumour characteristics into account. Radical cystectomy remains a highly complex procedure with considerable morbidity and risk of mortality, although lower rates are observed for higher hospital volumes (>20 cases/yr). With proper patient selection, trimodal therapy (chemoradiation) has comparable outcomes to radical cystectomy. Adjuvant chemotherapy after surgery improves disease-specific survival and overall survival (OS) in patients with high-risk disease who did not receive neoadjuvant treatment, and is strongly recommended. There is a weak recommendation for adjuvant nivolumab, as OS data are not yet available. Health-related quality of life should be assessed using validated questionnaires at baseline and after treatment. Surveillance is needed to monitor for recurrent cancer and functional outcomes. Recurrences detected on follow-up seem to have better prognosis than symptomatic recurrences.

CONCLUSIONS

This summary of the 2023 EAU guidelines provides updated information on the diagnosis and treatment of MMIBC for incorporation into clinical practice.

PATIENT SUMMARY

The European Association of Urology guidelines panel on muscle-invasive and metastatic bladder cancer has released an updated version of the guideline containing information on diagnosis and treatment of this disease. Recommendations are based on studies published up to May 4, 2022. Surgical removal of the bladder and bladder preservation are discussed, as well as updates on the use of chemotherapy and immunotherapy in localised and metastatic disease.

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.

Evaluation of response to gemcitabine plus cisplatin-based chemotherapy using positron emission computed tomography for metastatic bladder cancer

BACKGROUND

The purpose of the present study was to examine retrospectively the contribution of 18Fluorodeoxyglucose positron emission tomography computed tomography (18FDG-PET/CT) to the evaluation of response to first-line gemcitabine plus cisplatin-based chemotherapy in patients with metastatic bladder cancer.

AIM

To evaluate the response to Gemcitabine plus Cisplatin -based chemotherapy using 18FDG-PET/CT imaging in patients with metastatic bladder cancer.

METHODS

Between July 2007 and April 2019, 79 patients underwent 18FDG-PET/CT imaging with the diagnosis of Metastatic Bladder Carcinoma (M-BCa). A total of 42 patients (38 male, 4 female) were included in the study, and all had been administered Gemcitabine plus Cisplatin-based chemotherapy. After completion of the therapy, the patients underwent a repeat 18FDG-PET/CT scan and the results were compared with the PET/CT findings before chemotherapy according to European Organisation for the Research and treatment of cancer criteria. Mean age was 66.1 years and standard deviation was 10.7 years (range: 41-84 years).

RESULTS

Of the patients, seven (16.6%) were in complete remission, 17 (40.5%) were in partial remission, six (14.3%) had a stable disease, and 12 (28.6%) had a progressive disease. The overall response rate was 57.1 percent.

CONCLUSION

18FDG-PET/CT can be considered as a successful imaging tool in evaluating response to first-line chemotherapy for metastatic bladder cancer. Anatomical and functional data obtained from PET/CT scans may be useful in the planning of secondline and thirdline chemotherapy.

Staging fluorodeoxyglucose positron emission tomography/computed tomography for muscle-invasive bladder cancer: a nationwide population-based study

OBJECTIVE

To provide insight into the use and staging information on lymph-node involvement added by fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in patients with muscle-invasive bladder cancer (MIBC), based on a nationwide population-based cohort study.

PATIENTS AND METHODS

We analysed a nationwide cohort of patients with MIBC without signs of distant metastases, newly diagnosed in the Netherlands between November 2017 and October 2019. From this cohort, we selected patients who underwent pre-treatment staging with CT only or CT and FDG-PET/CT. The distribution of patients, disease characteristics, imaging findings, nodal status (clinical nodal stage cN0 vs cN+) and treatment were described for each imaging modality group (CT only vs CT and FDG-PET/CT).

RESULTS

We identified 2731 patients with MIBC: 1888 (69.1%) underwent CT only; 606 (22.2%) underwent CT and FDG-PET/CT, 237 (8.6%) underwent no CT. Of the patients who underwent CT only, 200/1888 (10.6%) were staged as cN+, vs 217/606 (35.8%) who underwent CT and FDG-PET/CT. Stratified analysis showed that this difference was found in patients with clinical tumour stage (cT)2 as well as cT3/4 MIBC. Of patients who underwent both imaging modalities and were staged with CT as cN0, 109/498 (21.9%) were upstaged to cN+ based on FDG-PET/CT. Radical cystectomy (RC) was the most common treatment within both imaging groups. Preoperative chemotherapy was more frequently applied in cN+ disease and in FDG-PET/CT-staged patients. Concordance of pathological N stage after upfront RC was higher among patients staged as cN+ with CT and FDG-PET/CT (50.0% pN+) than those staged as cN+ with only CT (39.3%).

CONCLUSION

Patients with MIBC who underwent pre-treatment staging with FDG-PET/CT were more often staged as lymph node positive, regardless of cT stage. In patients with MIBC who underwent CT and FDG-PET/CT, FDG-PET/CT led to clinical nodal upstaging in approximately one-fifth. Additional imaging findings may influence subsequent treatment strategies.

FDG-PET/CT for lymph node staging prior to radical cystectomy

BACKGROUND

¹⁸F-Fluorodeoxyglucose positron emission combined with computed tomography (FDG-PET/CT) has been proposed to improve preoperative staging in patients with bladder cancer subjected to radical cystectomy (RC).

OBJECTIVE

Our aim was to assess the accuracy of FDG-PET/CT for lymph node staging ascertained at the multidisciplinary tumour board compared to lymph node status in the surgical lymphadenectomy specimen obtained at RC, and to explore potential factors associated with false-positive FDG-PET/CT results.

DESIGN, SETTING AND PARTICIPANTS

Consecutive patients with bladder cancer undergoing RC with extended lymph node dissection between 2011 and 2019 without preoperative chemotherapy in a tertial referral cystectomy unit were included in the study.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSES

Sensitivity, specificity, positive and negative predictive values and likelihood ratios were calculated. Potential factors investigated for association with false-positive FDG-PET/CT were; bacteriuria within four weeks prior to FDG-PET/CT, Bacillus Calmette-Guerin (BCG) treatment within 12 months prior to FDG-PET/CT and transurethral resection of bladder tumour (TURB) within four weeks prior to FDG-PET/CT.

RESULTS

Among 157 patients included for analysis, 44 (28%) were clinically node positive according to FDG-PET/CT. The sensitivity and specificity for detection of lymph node metastasis were 50% and 84%, respectively, and the corresponding positive predictive and negative predictive values were 61% and 76%. Positive and negative likelihood ratios were 3.0 and 0.6, respectively. No association was found between bacteriuria, previous BCG treatment or TURB within 28 days and false-positive FDG-PET/CT results.

CONCLUSIONS

Preoperative FDG-PET/CT prior to RC had a clinically meaningful high specificity (84%) but lower sensitivity (50%) for detection of lymph node metastases compared to lymph node status in an extended pelvic lymphadenectomy template. We could not identify any factors associated with false-positive FDG-PET/CT outcomes.

Assessing the Performance of 18F-FDG PET/CT in Bladder Cancer: A Narrative Review of Current Evidence

INTRODUCTION

Lymph node (LN) involvement is a crucial determinant of prognosis for patients with bladder cancer, and an accurate staging is of utmost importance to better identify timely and appropriate therapeutic strategies. To improve the accuracy of LN detection, as an alternative to traditional methods such as CT or MRI, 18F-FDG PET/CT has been increasingly used. 18F-FDG PET/CT is also used in post-treatment restaging after neoadjuvant chemotherapy. The aim of this narrative literature review is to provide an overview of the current evidence on the use of 18F-FDG PET/CT in the diagnosis, staging, and restaging of bladder cancer, with a particular focus on its sensitivity and specificity for the detection of LN metastasis. We aim to provide clinicians with a better understanding of 18F-FDG PET/CT's potential benefits and limitations in clinical practice.

MATERIALS AND METHODS

We designed a narrative review starting from a wide search in the PubMed/MEDLINE and Embase databases, selecting full-text English articles that have examined the sensibility and specificity of PET/CT for nodal staging or restaging after neoadjuvant therapy in patients with bladder cancer. The extracted data were analyzed and synthesized using a narrative synthesis approach. The results are presented in a tabular format, with a summary of the main findings of each study.

RESULTS

Twenty-three studies met the inclusion criteria: fourteen studies evaluated 18F-FDG PET/CT for nodal staging, six studies examined its accuracy for restaging after neoadjuvant therapy, and three studies evaluated both applications. To date, the use of F-18 FDG PET/TC for detection of LN metastasis in bladder cancer is controversial and uncertain: some studies showed low accuracy rates, but over the years other studies have reported evidence of high sensitivity and specificity.

CONCLUSIONS

18F-FDG PET/CT provides important incremental staging and restaging information that can potentially influence clinical management in MIBC patients. Standardization and development of a scoring system are necessary for its wider adoption. Well-designed randomized controlled trials in larger populations are necessary to provide consistent recommendations and consolidate the role of 18F-FDG PET/CT in the management of bladder cancer patients.

The Implementation of FDG PET/CT for Staging Bladder Cancer: Changes in the Detection and Characteristics of Occult Nodal Metastases at Upfront Radical Cystectomy?

Occult lymph node (LN)-metastases are frequently found after upfront radical cystectomy (uRC) for bladder cancer (BC). We evaluated whether the implementation of 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG PET/CT) influenced nodal staging at uRC. All consecutive BC patients who underwent uRC with bilateral pelvic lymph node dissection (PLND) were identified and divided into two cohorts: cohort A consisted of patients staged with FDG PET/CT and contrast-enhanced CT (CE-CT) (2016-2021); cohort B consisted of patients staged with CE-CT only (2006-2011). The diagnostic performance of FDG PET/CT was assessed and compared with that of CE-CT. Thereafter, we calculated the occult LN metastases proportions for both cohorts. In total, 523 patients were identified (cohort A n = 237, and cohort B n = 286). Sensitivity, specificity, PPV and NPV of FDG PET/CT for detecting LN metastases were 23%, 92%, 42%, and 83%, respectively, versus 15%, 93%, 33%, 81%, respectively, for CE-CT. Occult LN metastases were found in 17% of cohort A (95% confidence interval (CI) 12.2-22.8) and 22% of cohort B (95% CI 16.9-27.1). The median size of LN metastases was 4 mm in cohort A versus 13 mm in cohort B. After introduction of FDG PET/CT, fewer and smaller occult LN metastases were present after uRC. Nevertheless, up to one-fifth of occult (micro-)metastases were still missed.

Carboplatin Induction Chemotherapy in Clinically Lymph Node–positive Bladder Cancer

Background

There are currently no guideline recommendations regarding the treatment of cisplatin-ineligible, clinically lymph node-positive (cN+) bladder cancer (BCa).

Objective

To investigate the oncological efficacy of gemcitabine/carboplatin induction chemotherapy (IC) in comparison to cisplatin-based regimens in cN+ BCa.

Design setting and participants

This was an observational study of 369 patients with cT2-4 N1-3 M0 BCa.

Intervention

IC followed by consolidative radical cystectomy (RC).

Outcome measurements and statistical analysis

The primary endpoints were the pathological objective response (pOR; ypT0/Ta/Tis/T1 N0) rate and the pathological complete response (pCR; ypT0N0) rate. We applied 3:1 propensity score matching (PSM) to reduce selection bias. Overall survival (OS) and cancer-specific survival (CSS) were compared across groups using the Kaplan-Meier method. Associations between the treatment regimen and survival endpoints were tested in multivariable Cox regression analyses.

Results and limitations

After PSM, a cohort of 216 patients was available for analysis, of whom 162 received cisplatin-based IC and 54 gemcitabine/carboplatin IC. At RC, 54 patients (25%) had a pOR and 36 (17%) had a pCR. The 2-yr CSS was 59.8% (95% confidence interval [CI] 51.9-69%) for patients who received cisplatin-based IC versus 38.8% (95% CI 26-57.9%) for those who received gemcitabine/carboplatin. For the pOR (p = 0.8), ypN0 status at RC (p = 0.5), and cN1 BCa subgroups (p = 0.7), there was no difference in CSS between cisplatin-based IC and gemcitabine/carboplatin. In the cN1 subgroup, treatment with gemcitabine/carboplatin was not associated with shorter OS (p = 0.2) or CSS (p = 0.1) on multivariable Cox regression analysis.

Conclusions

Cisplatin-based IC seems to be superior to gemcitabine/carboplatin and should be the standard for cisplatin-eligible patients with cN+ BCa. Gemcitabine/carboplatin may be an alternative treatment for selected cisplatin-ineligible patients with cN+ BCa. In particular, selected cisplatin-ineligible patients with cN1 disease may benefit from gemcitabine/carboplatin IC.

Patient summary

In this multicenter study, we found that selected patients with bladder cancer and clinical evidence of lymph node metastasis who cannot receive standard cisplatin-based chemotherapy before surgery to remove their bladder may benefit from chemotherapy with gemcitabine/carboplatin. Patients with a single lymph node metastasis may benefit the most.

PET Imaging in Bladder Cancer: An Update and Future Direction

Molecular imaging with positron emission tomography is a powerful tool in bladder cancer management. In this review, we aim to address the current place of the PET imaging in bladder cancer care and offer perspectives on potential future radiopharmaceutical and technological advancements. A special focus is given to the following: the role of [¹⁸F] 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography in the clinical management of bladder cancer patients, especially for staging and follow-up; treatment guided by [¹⁸F]FDG PET/CT; the role of [¹⁸F]FDG PET/MRI, the other PET radiopharmaceuticals beyond [¹⁸F]FDG, such as [⁶⁸Ga]- or [¹⁸F]-labeled fibroblast activation protein inhibitor; and the application of artificial intelligence.

A machine-learning-based combination of criteria to detect bladder cancer lymph node metastasis on [18F]FDG PET/CT: a pathology-controlled study

OBJECTIVES

Initial pelvic lymph node (LN) staging is pivotal for treatment planification in patients with muscle-invasive bladder cancer (MIBC), but [¹⁸F]FDG PET/CT provides insufficient and variable diagnostic performance. We aimed to develop and validate a machine-learning-based combination of criteria on [¹⁸F]FDG PET/CT to accurately identify pelvic LN involvement in bladder cancer patients.

METHODS

Consecutive patients with localized MIBC who performed preoperative [¹⁸F]FDG PET/CT between 2010 and 2017 were retrospectively assigned to training (n = 129) and validation (n = 44) sets. The reference standard was the pathological status after extended pelvic LN dissection. In the training set, a random forest algorithm identified the combination of criteria that best predicted LN status. The diagnostic performances (AUC) and interrater agreement of this combination of criteria were compared to a consensus of experts.

RESULTS

The overall prevalence of pelvic LN involvement was 24% (n = 41/173). In the training set, the top 3 features were derived from pelvic LNs (SUVmax of the most intense LN, and product of diameters of the largest LN) and primary bladder tumor (product of diameters). In the validation set, diagnostic performance did not differ significantly between the combination of criteria (AUC = 0.59 95%CI [0.43-0.73]) and the consensus of experts (AUC = 0.64 95%CI [0.48-0.78], p = 0.54). The interrater agreement was equally good with Κ = 0.66 for both.

CONCLUSION

The developed machine-learning-based combination of criteria performs as well as a consensus of experts to detect pelvic LN involvement on [¹⁸F]FDG PET/CT in patients with MIBC.

KEY POINTS

• The developed machine-learning-based combination of criteria performs as well as experts to detect pelvic LN involvement on [¹⁸F]FDG PET/CT in patients with muscle-invasive bladder cancer. • The top 3 features to predict LN involvement were the SUVmax of the most intense LN, the product of diameters of the largest LN, and the product of diameters of the primary bladder tumor.

Added Clinical Value of 18F-FDG-PET/CT to Stage Patients With High-Risk Non-Muscle Invasive Bladder Cancer Before Radical Cystectomy

INTRODUCTION AND OBJECTIVES

18F-fluorodeoxyglucose positron-emission tomography-computed tomography (FDG-PET/CT) is increasingly used in the preoperative staging of patients with muscle-invasive bladder cancer. The clinical added value of FDG-PET/CT in high-risk non-muscle invasive bladder cancer (NMIBC) is unknown. In this study, the value of FDG-PET/CT in addition to contrast enhanced (CE)-CT was evaluated in high-risk NMIBC before radical cystectomy (RC).

MATERIALS AND METHODS

This is a retrospective analysis of consecutive patients with high risk and very-high risk urothelial NMIBC scheduled for RC in a tertiary referral center between 2011 and 2020. Patients underwent staging with CE-CT (chest and abdomen/pelvis) and FDG-PET/CT. We assessed the clinical disease stage before and after FDG-PET/CT and the treatment recommendation based on the stage before and after FDG-PET/CT. The accuracy of CT and FDG-PET/CT for identifying metastatic disease was defined by the receiver-operating curve using a reference-standard including histopathology/cytology (if available), imaging and follow-up.

RESULTS

A total of 92 patients were identified (median age: 71 years). In 14/92 (15%) patients, FDG-PET/CT detected metastasis (12 suspicious lymph nodes and 4 distant metastases). The disease stage changed in 11/92 (12%) patients based on additional FDG-PET/CT findings. FDG-PET/CT led to a different treatment in 9/92 (10%) patients. According to the reference standard, 25/92 (27%) patients had metastases. The sensitivity, specificity and accuracy of FDG-PET/CT was 36%, 93% and 77% respectively, versus 12%, 97% and 74% of CE-CT only. The area under the ROC curve was 0.643 for FDG-PET/CT and 0.545 for CT, P = .036.

CONCLUSION

The addition of FDG-PET/CT to CE-CT imaging changed the treatment in 10% of patients and proved to be a valuable diagnostic tool in a selected subgroup of NMIBC patients scheduled for RC.

IDH2 stabilizes HIF-1α-induced metabolic reprogramming and promotes chemoresistance in urothelial cancer

Drug resistance contributes to poor therapeutic response in urothelial carcinoma (UC). Metabolomic analysis suggested metabolic reprogramming in gemcitabine-resistant urothelial carcinoma cells, whereby increased aerobic glycolysis and metabolic stimulation of the pentose phosphate pathway (PPP) promoted pyrimidine biosynthesis to increase the production of the gemcitabine competitor deoxycytidine triphosphate (dCTP) that diminishes its therapeutic effect. Furthermore, we observed that gain-of-function of isocitrate dehydrogenase 2 (IDH2) induced reductive glutamine metabolism to stabilize Hif-1α expression and consequently stimulate aerobic glycolysis and PPP bypass in gemcitabine-resistant UC cells. Interestingly, IDH2-mediated metabolic reprogramming also caused cross resistance to CDDP, by elevating the antioxidant defense via increased NADPH and glutathione production. Downregulation or pharmacological suppression of IDH2 restored chemosensitivity. Since the expression of key metabolic enzymes, such as TIGAR, TKT, and CTPS1, were affected by IDH2-mediated metabolic reprogramming and related to poor prognosis in patients, IDH2 might become a new therapeutic target for restoring chemosensitivity in chemo-resistant urothelial carcinoma.

Positron Emission Tomography/Computed Tomography for Staging of Bladder Cancer: A Continuing Clinical Controversy

Fluorodeoxyglucose-based positron emission tomography/computed tomography is increasingly being used for staging of muscle-invasive bladder cancer before treatment. However, international clinical guidelines are hesitant to recommend this approach, as conclusive scientific evidence on its usefulness is lacking. The question is whether and how this evidence can be obtained.

Head-to-head Intra-individual Comparison of [68Ga]-FAPI and [18F]-FDG PET/CT in Patients with Bladder Cancer

AIM/PURPOSE

Fibroblast activation protein-(FAP)-ligands, a novel class of tracers for PET/CT imaging, demonstrated promising results in previous studies in various malignancies compared to standard [¹⁸F]FDG PET/CT. ⁶⁸Ga-labeled fibroblast activation protein inhibitor-([⁶⁸Ga]Ga-DOTA-FAPI)-PET/CT impresses with sharp contrasts in terms of high tumor uptake and low background noise leading to clear delineation. [¹⁸F]FDG PET/CT has limited accuracy in bladder cancer due to high background signal. Therefore, we sought to evaluate the diagnostic potential of [⁶⁸Ga]FAPI in patients with bladder cancer.

MATERIAL AND METHODS

This retrospective analysis consisted of 8 patients (median age 66), 7 of whom underwent both [⁶⁸Ga]FAPI and [¹⁸F]FDG PET/CT scans with a median time interval of 5 days (range 1-20 days). Quantification of tracer uptake was determined with SUV_max and SUV_mean. Furthermore, the tumor-to-background ratio (TBR) was derived by dividing the SUV_max of tumor lesions by the SUV_max of adipose tissue, skeletal muscle, and blood pool.

RESULTS

Overall, 31 metastases were detected in five patients including lymph node metastases (n = 23), bone metastases (n = 4), lung metastases (n = 3), and a peritoneal metastasis (n = 1). In one patient, [⁶⁸Ga]FAPI demonstrated significant uptake in the primary tumor located in the bladder wall. [⁶⁸Ga]FAPI-PET/CT demonstrated significantly higher uptake compared to [¹⁸F]FDG PET/CT with higher mean SUV_max (8.2 vs. 4.6; p = 0.01). Furthermore, [⁶⁸Ga]FAPI detected additional 30% (n = 9) lesions, missed by [¹⁸F]FDG. TBR demonstrated favorable uptake for [⁶⁸Ga]FAPI in comparison to [¹⁸F]FDG. Significant differences were determined with regard to metastasis/blood pool ([⁶⁸Ga]FAPI 5.3 vs [¹⁸F]FDG 1.9; p = 0.001).

CONCLUSION

[⁶⁸Ga]FAPI-PET/CT is a promising diagnostic radioligand for patients with bladder cancer. This first described analysis of FAP-ligand in bladder cancer revealed superiority over [¹⁸F]FDG in a small patient cohort. Thus, this so far assumed potential has to be confirmed and extended by larger and prospective studies.

Prediction of pathological response following neoadjuvant chemotherapy in patients with muscle-invasive bladder cancer: the PRE-PREVENCYS trial

Background

The recommended treatment for patients with non-metastatic muscle-invasive bladder cancer (MIBC) is neoadjuvant chemotherapy (NAC) and radical cystectomy (RC). Following NAC, 20–40% of patients experience a complete pathological response (pCR) in the RC specimen and these patients have excellent long-term overall survival. Subject to debate is, however, whether patients with a pCR to NAC benefit from RC, which is a major surgical procedure with substantial morbidity, and if these patients might be candidates for close surveillance instead. However, currently it is not possible to accurately identify patients with a pCR to NAC in whom RC might be withheld. The objective of this study is to assess whether pathological response in the RC specimen after NAC can be predicted based on clinical, radiological, and histological variables and on a wide set of molecular biomarkers assessed in tissue, blood and urine.

Methods

This is a multicentre, prospective cohort study, including patients with cT2a-T4a N0-N1 M0 urothelial cell MIBC who are scheduled to undergo cisplatin-based NAC followed by RC. Prior to start of therapy, a 2-Deoxy-2-[18F] fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) is performed. Response to NAC is evaluated by CT-scan. Blood and urine, including cytology, are prospectively collected for biomarker analyses before and after NAC. Immediately before RC, participants undergo cystoscopy with bimanual examination and a re-staging transurethral resection (TUR) of all visible cancerous lesions or with biopsies from scar tissue. Subsequently, RC is performed in all patients. Tissue from the diagnostic TUR, the re-staging TUR, and the RC specimen is examined for the presence of urothelial cancer carcinoma and DNA and RNA is isolated for molecular analysis. The primary endpoint is the pathological stage (ypTN) in the RC and ePLND specimen and its association with clinical response.

Discussion

If the PRE-PREVENCYS trial shows that the absence of residual disease after NAC in patients with MIBC is accurately predicted, a randomized controlled trial is scheduled comparing the overall survival of NAC plus RC versus NAC followed by close surveillance for patients with a clinically complete response (PREVENCYS trial).

Trial registration

Netherlands Trial Register: NL8678; Registered 20 May 2020 https://www.trialregister.nl/trial/8678

FAP imaging in rare cancer entities-first clinical experience in a broad spectrum of malignancies

PURPOSE

⁶⁸ Ga-FAPI (fibroblast activation protein inhibitor) is a rapidly evolving and highly promising radiotracer for PET/CT imaging, presenting excellent results in a variety of tumor entities, particularly in epithelial carcinomas. This retrospective analysis sought to evaluate the potential and impact of FAPI-PET/CT in rare cancer diseases with respect to improvement in staging and therapy, based on tracer uptake in normal organs and tumors.

MATERIAL AND METHODS

Fifty-five patients with rare tumor entities, defined by a prevalence of 1 person out of 2000 or less, received a ⁶⁸ Ga-FAPI-PET/CT scan. Fourteen women and 41 men (median age 60) were included within the following subgroups: cancer of unknown primary (n = 10), head and neck cancer (n = 13), gastrointestinal and biliary-pancreatic cancer (n = 17), urinary tract cancer (n = 4), neuroendocrine cancer (n = 4), and others (n = 7). Tracer uptake was quantified by standardized uptake values SUVmax and SUVmean and the tumor-to-background ratio (TBR) was determined (SUVmax tumor/SUVmean organ).

RESULTS

In 20 out of 55 patients, the primary tumor was identified and 31 patients presented metastases (n = 88), characterized by a high mean SUVmax in primary (10.1) and metastatic lesions (7.6). The highest uptake was observed in liver metastases (n = 6) with a mean SUVmax of 9.8 and a high TBR of 8.7, closely followed by peritoneal carcinomatosis (n = 16) presenting a mean SUVmax of 9.8 and an excellent TBR of 29.6. In terms of the included subgroups, the highest uptake regarding mean SUVmax was determined in gastrointestinal and biliary-pancreatic cancer with 9.8 followed closely by urinary tract cancer with 9.5 and head and neck cancer (9.1).

CONCLUSION

Due to excellent tumor visualization and, thereby, sharp contrasts in terms of high TBRs in primary and metastatic lesions in different rare malignancies, ⁶⁸ Ga-FAPI-PET/CT crystallizes as a powerful and valuable imaging tool, particularly with respect to epithelial carcinomas, and therefore an enhancement to standard diagnostics imaging methodologies. The realization of further and prospective studies is of large importance to confirm the potential of FAP imaging in oncology.

The role of 18F-FDG PET/CT scan compared to CT-scan alone for lymph node staging before radical cystectomy in patients with bladder cancer

BACKGROUND

Accurate Lymph node (LN) staging before radical cystectomy (RC) in patients with bladder cancer (BC) is crucial to improve patient's management. 18F-fluorodeoxyglucose positron-emission tomography-computed tomography (FDG-PET-CT) become widely used in the loco-regional staging of BC. The diagnostic performance of PET-CT in preoperative LN staging of BC is still unknown due to lacking large trials.

OBJECTIVES

We aim to evaluate the diagnostic value of PET-CT scan, compared with CT scan alone for preoperative LN staging of BC.

PATIENTS AND METHODS

From January 2010 to November 2020, we retrospectively reviewed the records of 300 patients undergoing RC for muscle-invasive BC and high-risk non-muscle-invasive BC. All patients had PET-CT and CT of abdomen and pelvis to assess for pelvic LN metastases before RC. Patients were excluded from analysis if they had neoadjuvant chemotherapy (NAC). Sensitivity, specificity, and accuracy for detecting pelvic LN metastases were determined by comparing the results of the FDG PET-CT and CT alone to the final histopathology reports obtained after RC.

RESULTS

LN metastasis was confirmed histology in 134 patients (44.7%). On a patient-based analysis, PET-CT, and CT showed a sensitivity of 40.3% and 13.4 %, respectively, a specificity of 79.5% and 86.7 %, respectively, positive predictive value (PPV) of 61.4% and 45%, respectively, and negative predictive value (NPV) of 62.3% and 55.4%, respectively. The diagnostic accuracy of PET-CT scan depends on multiple preoperative and postoperative factors.

CONCLUSION

PET-CT is more accurate than CT-scan alone for preoperative LN staging in patients with BC.