Original Study Interim Fluorine-18 Fluorodeoxyglucose Po Emission Tomography for Early Metabolic A of Therapeutic Response to Chemotherap Metastatic Transitional Cell Carcinoma Patrizia Giannatempo, 1 Alessandra Alessi, 2 Rosalba Miceli, 3 Daniele Raggi, 1 Elena Farè, 1 Nicola Nicolai, 4 Gianluca Serafini, 2 Barbara Padovano, 2 LuigiPiva, 4 Davide Biasoni, 4 Tullio Torelli, 4 Mario Catanzaro, 4 Silvia Stagni, 4 Massimo Maffezzini, 4 LuigiMariani, 3 Alessandro M. Gianni, 1,5 Guru Sonpavde, 6 Roberto Salvioni, 4 Andrea Necchi, 1 Flavio Crippa 2 Abstract Fluorine-18 fluorodeoxyglucose positron emission tomography is increasingly used by many centers for staging and response assessment of metastatic transitional cell carcinoma.We prospectively evaluated 31 patients undergoing metabolic restaging after only 2 cycles of first-line chemotherapy (PET2). Early metabolic response was associated with patient outcome. The aim was to provide a proof of principle for a risk-adapted approach based on PET2 that may guide new trial design for early-recognized unresponsive patients. Background: The prognostic impact of early metabolic response by fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) after 2 cycles offirst-line chemotherapy is still unrecognized in metastatic transitional cell carcinoma (TCC).Patients and Methods: Patients with metastatic TCC receiving the modified combination of methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC), according to institutional protocol, underwent compute tomography (CT) and FDG-PET imaging at baseline, a restaging with PET imaging after 2 cycles only (PET2), and a CT ( FDG-PET) scan at the end of treatment and during follow-up. Progression-free survival (PFS)and overall survival (OS) were estimated with the KaplaneMeier method; univariate (UVA) and multivariate (MVA) Cox models were fitted Prespecified variables were the presence of visceral metastases, nodal or soft tissue disease, and early PET response Results: In the period from May 2010 to October 2012, 31 patients with Eastern Cooperative Oncology Group per- formance status 0 received the modified MVAC regimen every 3 weeks. In all,6 patients (19.3%) had a complete response (CR) and 17 (54.8%) a partial metabolic response (PR), 4 had stable disease (SD), and 4 progressed. PET2 responders had a median PFS of 8 months (95 % CI, 7-11 mo) compared with 3 months (95 % CI, 2-5 mo) of patients without response (P ¼ .024). They also had a significant benefit in 8-month PFS (P < .001 via Klein test) and 15-mont OS (P ¼ .016). PET2 response was significant for PFS in both UVA and MVA Cox models (P ¼ .027 and P ¼ .023, respectively). Conclusion: PET response after 2 cycles of first-line chemotherapy, compared with detection by early CT, was associated with longer PFS and OS in advanced TCC and warrants further investigation in the field. ClinicalGenitourinary Cancer, Vol. - , No. - , - -- ª 2014 Elsevier Inc. All rights reserved. Keywords:Imaging biomarkers, Metabolic response, Positron emission tomography, Transitional cellcarcinoma, Urothelial cancer Poster presented at the 17th European Cancer Organisation (ECCO) e38th European Society for Medical Oncology (ESMO)e32nd European Society for Radiotherapy and Oncology (ESTRO) European Cancer Congress; September 27-October 1, 2013; Amsterdam, The Netherlands Poster presented at the 14th Annual Meeting of the Society of Urologic Oncology (SUO);December 4-6, 2013;Bethesda, MD Poster presented at the 2014 Genitourinary Cancers Symposium; January 30-February 4,2014;San Francisco, CA 1 Department of Medical Oncology 2 Nuclear Medicine and PET Unit 3 Clinical Epidemiology and Trials Organization Unit 4 Department of Surgery, Urology Unit Fondazione IRCCS Istituto Nazionale dei Tumori,Milan,Italy 5 University of Milan School of Medicine, Milan,Italy 6 University of Alabama (UAB) Comprehensive Cancer Center, Birmingham, AL Submitted: Jan 14,2014;Revised: Mar 3,2014;Accepted: Mar 11,2014 Address for correspondence: Andrea Necchi, MD, Department of Medical Oncology, Medical Oncology 2 Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, 20133 Milano, Italy E-mailcontact: andrea.necchi@istitutotumori.mi.it 1558-7673/$ - see frontmatter ª 2014 Elsevier Inc. Allrights reserved. http://dx.doi.org/10.1016/j.clgc.2014.03.007 Clinical Genitourinary Cancer Month 2014 - 1