[18F]Fluoro-Deoxy-Glucose positron emission tomography to evaluate lymph node involvement in patients with muscle-invasive bladder cancer receiving neoadjuvant pembrolizumab.

Data regarding the role of positron emission tomography/computed tomography (PET/CT) to stage lymph nodes in patients receiving neoadjuvant immunotherapy before radical cystectomy are lacking. The aim of this study is to evaluate the role of PET/CT to predict the pathologic lymph node involvement (LNI) in patients with MIBC receiving neoadjuvant pembrolizumab within the PURE-01 trial (NCT02736266).

Three courses of pembrolizumab were administered before radical cystectomy and extended pelvic lymph node dissection in clinical T2-4aN0M0 MIBC based on contrast-enhanced CT scan. LNI was also assessed with PET/CT before and after treatment. PET/CT results were compared with histopathological findings. The ability of baseline and post-therapy PET/CT to evaluate LNI was assessed, and univariate logistic regression analyses were performed.

From February 2017 to August 2019, a total of 108 patients and 105 patients had evaluable baseline and post-pembrolizumab scans, respectively. The sensitivity to detect LNI was 27% and 37.5% for pre- and post-pembrolizumab PET/CT, and specificity was 97% and 98%, respectively. In total, 4 of 7 patients (57%) showing baseline FDG-uptake had LNI vs. 11 of 101 (11%) with no baseline uptake. All but 1 of the 7 patients did not respond to pembrolizumab. Both pre- and post-pembrolizumab PET/CT significantly predicted LNI (P = 0.004 and P < 0.001) at univariate analyses. Our results warrant further validation in larger datasets.

PET/CT performance does not justify its use in routine practice for cN0 MIBC. However, our preliminary data revealed opportunities for the use of baseline PET/CT, within clinical trials, to optimally select patients with MIBC who are best suited for neoadjuvant immunotherapy strategies. Validation in larger datasets, as well as a cost analysis, are needed.

Urologic oncology. 2020 Oct 15 [Epub ahead of print]

Laura Marandino, Antonella Capozza, Marco Bandini, Daniele Raggi, Elena Farè, Filippo Pederzoli, Andrea Gallina, Umberto Capitanio, Marco Bianchi, Giorgio Gandaglia, Nicola Fossati, Maurizio Colecchia, Patrizia Giannatempo, Gianluca Serafini, Barbara Padovano, Andrea Salonia, Alberto Briganti, Francesco Montorsi, Alessandra Alessi, Andrea Necchi

Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. Electronic address: ., Department of Nuclear Medicine - PET Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy., Unit of Urology, Urological Research Institute (URI), IRCCS Ospedale San Raffaele, Milan, Italy., Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy., Unit of Urology, Urological Research Institute (URI), IRCCS Ospedale San Raffaele, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy., Department of Pathology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

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