Resection margin status in pancreatic cancer surgery: is it really less important than the N status?

We read with great interest the article by Tummers et al. 1 regarding the influence of resection margin status on overall survival (OS) and disease-free survival (DFS) after pancreatoduodenectomy for ductal adenocarcinoma. Despite the excellent study design, we have some considerations to stimulate discussion on this interesting topic. In line with the literature 2, the authors confirmed the negative prognostic role of the R1 status. Surprisingly however, R status became a negligible factor when lymph nodes metastases (N1) were present. More specifically, no difference in OS and DFS was noted between the R0 and R1 groups when N1 was evidenced. This conclusion was drawn on the basis of the seventh edition of the TNM classification, according to which N1 is defined as the presence (independent of number) of positive lymph nodes. For the purpose of the study, the more recent eighth edition of the TNM classification would have been more suitable, since a subdivision between of N1 and N2 has been introduced according to the number of positive lymph nodes encountered (three or more, respectively). In our opinion, this would have contributed significantly in avoiding an overestimation of the lymph node parameter, since the number of positive lymph nodes has already been demonstrated to be an influencing factor on OS for pancreatic cancer 3. As a consequence, a more precise classification would, at the same time, guarantee better patient selection for potential neoadjuvant treatment in resectable pancreatic adenocarcinomas, as proposed by the authors. As a second point, the authors did not report any difference in terms of early recurrence rate between the R1 (28 patients, 51 per cent) and R0 (27 patients, 49 per cent) cohorts, although the P value approached significance (P = 0.07). In this regard, the result could have been affected by the small sample size for comparison. In addition, it would be interesting to know how many of these patients had undergone adjuvant radiotherapy which is generally employed in cases of margins positivity and could have suppressed the impact of the R status