ORIGINAL ARTICLE Tumour origin and R1 rates in pancreatic resections: towards consilience in pathology reporting Munita Bal 1 & Swapnil Rane 1 & Sanjay Talole 2 & Mukta Ramadwar 1 & Kedar Deodhar 1 & Prachi Patil 3 & Mahesh Goel 4 & Shailesh Shrikhande 4 Received: 7 January 2018 /Revised: 26 July 2018 /Accepted: 29 July 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract To evaluate differences in the R1 rates of ampullary (AC), pancreatic (PC), and distal bile duct (DBD) cancers in pancreatoduodenectomies (PD) using standardised pathology assessment. Data of PD (2010–2011) analysed in accordance with the Royal College of Pathologists (UK) protocol, were retrieved. Clinicopathologic features, including frequency, topography, and mode of margin involvement in AC (n = 87), PC (n = 18), and DBD (n = 5) cancers were evaluated. The R1 rate was 7%, 67%, and 20% in the AC, PC, and DBD cancers (p < 0.001). Within the PC cohort, R1 rate was heterogeneous (chemo-naïve, 77%; post-neoadjuvant, 40%). Commonest involved margins were as follows: posterior in overall PD (35%), AC (43%), overall PC (33%), and post-neoadjuvant PC (100%); superior mesenteric artery margin in chemo-naïve PC (38%) and common bile duct margin in DBD (100%) cancers. In AC, majority (66%) of R1 were signet ring cell type. Indirect margin involvement due to tumour within lymph node, perineural sheath or lymphovascular space was observed in 26% cases, and altered R1 rate in AC, PC, and DBD cohorts by 1%, 12%, and 0%, respectively. Although not statistically significant, patients with R1 had lower disease-free survival than those with R0 (mean, 25.4 months versus 44.4 months). Tumour origin impacts R1 data in PD necessitating its accurate classification by pathologists. Indirect involvement, histology, and neoadjuvant therapy influence the R1 rate, albeit in a minority of cases. Generating cogent R1 data based on standardised pathology reporting is the foremost need of the hour. Keywords Resection margin . R1 rate . Pancreatoduodenectomy . Tumour origin . Standardised pathology evaluation protocol Introduction Resection margin status is a key prognostic marker influenc- ing outcome following a pancreatoduodenectomy (PD) resec- tion. Traditionally, evaluation of pancreatic neck (PN), common bile duct (CBD), proximal stomach/duodenal, and distal enteric margin has been customary for PD specimens. However, the past decade has brought to attention the impor- tance of evaluating additional circumferential resection margins (CRM) by demonstrating a high rate of their involve- ment [1–4]. Employing a standardised pathology evaluation protocol that incorporates CRM assessment has shown a significant increase in the microscopic margin positivity or R1 rates, from 17–51% [5–8] to 76–85% [1–4]. Moreover, studies have also shown that RM status correlates better with survival after using standardised pathology evaluation protocol [1–4, 9, 10]. While pathologists are beginning to take cognisance of the importance of CRM in PD resections, many aspects of R1 continue to remain controversial. International consensus for the optimal specimen dissection methodology, clinically rele- vant margins, adequate microscopic clearance (whether 0 mm or < 1 mm), and significance of tumour within lymphovascular/ perineural space or a lymph node (LN) at margin is lacking [11–14]. Recently, literature on R1 rates Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00428-018-2429-7) contains supplementary material, which is available to authorized users. * Munita Bal munitamenon@gmail.com 1 Department of Pathology, Tata Memorial Centre, Mumbai 400012, India 2 Department of Epidemiology and Statistics, Tata Memorial Centre, Mumbai, India 3 Department of Digestive Diseases and Nutrition, Tata Memorial Centre, Mumbai, India 4 Department of Surgical Oncology, Tata Memorial Centre, Mumbai, India Virchows Archiv https://doi.org/10.1007/s00428-018-2429-7