Application of 18F-FDG PET/CT imaging in diagnosing bladder tumor metastasis lesions

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

18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in muscle-invasive bladder cancer

PURPOSE OF REVIEW

In this narrative review, we assessed the role of F-fluoro-2-deoxy-D-glucose-positron emission tomography/CT (FDG-PET/CT) in preoperative staging and response evaluation of neoadjuvant chemotherapy in muscle-invasive bladder carcinoma (MIBC), and to assess its incremental value to contrast-enhanced (CE)CT and MRI in terms of patient management at initial diagnosis and detection of recurrence.

RECENT FINDINGS

A literature search in PubMed yielded 46 original reports, of which 15 compared FDG-PET/CT with CECT and one with MRI. For primary tumor assessment, FDG-PET/CT proved not accurate enough (13 reports; n = 7-70). For lymph node assessment, sensitivity of FDG-PET/CT is superior to CT with comparable specificity in 19 studies (n = 15-233). For detection of distant metastases, data from eight studies (n = 43-79) suggests that FDG-PET/CT is accurate, although comparative studies are lacking. Limited evidence (four studies, n = 19-50) suggests that FDG-PET/CT is not accurate for response evaluation of neoadjuvant chemotherapy. FDG-PET/CT incited change(s) in patient management in 18-68% of patients (five reports; n = 57-103). For detection of recurrence, seven studies (n = 29-287) indicated that FDG-PET/CT is accurate.

SUMMARY

Most studies evaluated FDG-PET/CT for lymph node assessment and reported higher sensitivity than CT, with comparable specificity. FDG-PET/CT showed incremental value to CECT for recurrence and often incited change(s) in patient management.

Parotid metastasis from carcinoma urinary bladder treated with CyberKnife-based stereotactic body radiotherapy: case report and review of literature

Metastases to the parotid region are relatively infrequent and originate primarily from head and neck cancer. Metastases of an infraclavicular origin are uncommon. Moreover, metastasis from the carcinoma of urinary bladder (CUB) to any part of the head and neck, including parotid gland, is rare. Surgery and chemotherapy are usually offered. We report a case of solitary parotid metastasis from CUB, who was successfully treated with stereotactic body radiotherapy (SBRT) using CyberKnife. SBRT is a safe alternative in cases unwilling/unfit for surgery.