Human cytomegalovirus and Epstein-Barr virus infection impact on super(18)F-FDG PET/CT SUVmax, CT volumetric and KRAS-based parameters of patients with locally advanced rectal cancer treated with neoadjuvant therapy

Purpose: It has long been debated whether human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) are associated with rectal cancer. The gene products of HCMV and EBV contribute to cell-cycle progression, mutagenesis, angiogenesis and immune evasion. The aim of this prospective study was to analyse the association between infection of a tumour by HCMV and EBV and clinical, histological, metabolic ( super(18)F-FDG uptake), volumetric (from CT) and molecular (KRAS status) features and long-term outcomes in a homogeneously treated group of patients with locally advanced rectal cancer. Methods: HCMV and EBV were detected in pretreatment biopsies using polymerase chain reaction (PCR). The Cox proportional hazards regression model was used to explore associations between viral infection and disease-free survival (DFS) and overall survival (OS). Results: We analysed 37 patients with a median follow-up of 74 months (range 5-173 months). Locoregional control, OS and DFS at 5 years were 93 %, 74 % and 71 %, respectively. Patients with HCMV/EBV coinfection had a significantly higher maximum standardized uptake value than patients without viral coinfection (p=0.02). Significant differences were also observed in staging and percentage relative reduction in tumour volume between patients with and without HCMV infection (p