Radiological prediction of positive circumferential resection margin in oesophageal cancer

Abstract

A positive circumferential resection margin (CRM) is regarded as a poor prognostic indicator in oesophageal cancer (OC) but its prediction can be challenging. MRI is used to predict a threatened CRM in rectal cancer but is not commonly performed in OC unlike PET/CT, which is now routinely used. Therefore, this study assessed the additional predictive value of PET-defined tumour variables compared with EUS and CT T-stage. The prognostic significance of CRM status was also assessed. Materials and Methods This retrospective study included 117 consecutive patients [median age 64.0 (range 24-78), 102 males, 110 adenocarcinomas, 6 squamous cell carcinoma (SCC), 1 neuro-endocrine] treated between 1 st March 2012 and 31 st July 2015. A binary logistic regression model tested 5 staging variables; EUS T-stage (T2 vs T3), CT T-stage (T2 vs T3), PET metabolic tumour length (MTL), PET metabolic tumour width (MTW) and the maximum standardised uptake value (SUVmax). Results The CRM was positive in 43.6%. Sixty-seven (57.3%) patients received neoadjuvant chemotherapy (NACT), 31 patients (26.5%) underwent surgery alone and 19 patients (16.2%) had neo-adjuvant chemo-radiotherapy (NACRT). Median overall survival (OS) was 36.0 months (95% confidence interval (CI) 24.1-47.9) and the 2-year OS was 55.4%. A binary logistic regression model showed EUS ≥T3 tumours were independently and significantly more likely to have a positive CRM than EUS ≤T2 tumours (HR 5.188, 95% CI 1.265-21.273, p=0.022). CT T-stage, PET MTL, PET MTW and SUVmax were not significantly associated with CRM status (p=0.783, 0.852, 0.605 and 0.413, respectively). There was a significant difference in OS between CRM positive and negative groups (X 2 4.920, df 1, p=0.027). Conclusion Advanced EUS T-stage is associated with a positive CRM, but PET-defined tumour variables are unlikely to provide additional predictive information. This study demonstrates the continued benefit of EUS as part of a multi-modality OC staging pathway.