LETTER TO THE EDITOR Retrospective Studies and Pancreatic Adenocarcinoma: How Far Can We Backdate? To the Editor: read with interest 2 articles recently published in Annals of Surgery: “Should portal vein be routinely resected during pancreaticoduodenectomy for adenocarcinoma?” by Turrini et al1 and “Pancreatic ductal adenocarcinoma: Is There a Survival Difference for R1 Resections Versus Locally Advanced Unresectable Tumors? What Is a ‘True’ R0 Resection?” by Konstantinidis et al.2 The first article describes a questionable series of patients with a survival benefit after portal vein (PV)/superior mesenteric vein (SMV) resection and absence of vascular tumor infiltration; the second article compares the survival of patients with different grades of residual disease and unresectable disease. Although focused on very different topics, these studies have something in common: they both use retrospective data (20002010 and 1993-2008, respectively). In the last years, our understanding of pancreatic cancer has definitely changed. Many authors, for instance, have shown us that when we use a standardized protocol to analyze our resection margin, the vast majority of our operations for pancreatic cancer is palliative (R1).3,4 In fact, in the first study, the pathological preparation of the specimen is not well described and in the second study the protocol used is the same that was described in 19965 and the majority of resected patients received an R0 resection. How should the surgical community interpret these results? Second, the introduction of endoscopic ultrasound (EUS) in most of the hepatopancreatobiliary (HPB)-specialized centers and the use of multislice computed tomographic scan integrated with magnetic resonance imaging and positron emission tomography has certainly improved our preoperative assessment of PV/SMV involvement and locally unresectable tumors.6,7 With regard to the first article, because apparently computed tomography was used, would a more accurate preoperative imaging

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Disclosure: No conflict of interest and there are no funding sources. C 2014 Wolters Kluwer Health, Inc. All Copyright  rights reserved. ISSN: 0003-4932/14/26103-e0084 DOI: 10.1097/SLA.0000000000000416

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demonstrating no signs of vascular involvement impact the decision to perform a vascular resection? And in the second article, how was the unresectability assessed? Apparently half of the patients explored for resection were unresectable: it seems a very high number of laparotomies and I wonder why the definition of unresectable tumors was based on intraoperative findings and how it was made. My final question to both authors is “how far can we backdate our data in retrospective studies on pancreatic cancer?” Fabio Ausania, MD HPB Surgery Hospital Xeral, Vigo Pontevedra, Spain [email protected]

REFERENCES 1. Turrini O, Ewald J, Barbier L, et al. Should portal vein be routinely resected during pancreaticoduodenectomy for adenocarcinoma. Ann Surg. 2013;257:726–730. 2. Konstantinidis IT, Warshaw AL, Allen JN, et al. Pancreatic ductal adenocarcinoma: is there a survival difference for R1 resections versus locally advanced unresectable tumors? What is a “True” R0 resection? Ann Surg. 2013;257: 731–736. 3. Esposito I, Kleeff J, Bergmann F, et al. Most pancreatic cancer resections are R1. Ann Surg Oncol. 2008;15:1651–1660. 4. Verbeke CS, Leitch D, Menon KV, et al. Redefining the R1 resection in pancreatic cancer. Br J Surg. 2006;93:1232–1237. 5. Staley CA, Cleary KR, Abbruzzese JL, et al. The need for standardized pathologic staging of pancreaticoduodenectomy specimens. Pancreas. 1996;12:373–380. 6. Kauhanen SP, Komar G, Sepp¨anen MP, et al. A prospective diagnostic accuracy study of 18Ffluorodeoxyglucose positron emission tomography/ computed tomography, multidetector row computed tomography, and magnetic resonance imaging in primary diagnosis and staging of pancreatic cancer. Ann Surg. 2009;250:957–963. 7. Wong JC, Lu DS. Staging of pancreatic adenocarcinoma by imaging studies. Clin Gastroenterol Hepatol. 2008;6:1301–1308.

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e want to thank Dr Ausania for his interest in our article. With regard to his inquiries, our response is as follows: His first point is that with the use of a standardized protocol most pancreatic resec-

tions harbor microscopically positive margins (R1). At Massachusetts General Hospital, we have a detailed pathologic protocol. As stated in our discussion, we want to emphasize that the difference in the percentage of microscopically positive margins among studies can be at least partially attributed to whether a 1-mm margin is considered positive or negative. In our experience, similar to others,1 the survival of patients with a surgical margin within 1 mm was similar to those with R1 resection.2 Dr Ausania’s second point questions why unresectability was based on intraoperative findings in half the patients rather than by preoperative imaging. At Massachusetts General Hospital, patients with locally advanced tumors are explored not only to attempt a curative resection but also to offer a palliative bypass procedure or to deliver intraoperative radiation therapy. Thus, those patients who were operated on with potentially curative intent (plan A) but were found to be locally unresectable, half of all those explored received appropriate treatment (plan B). With regard to his final comment as to how far we can backdate our data in retrospective studies, perhaps a more important challenge, which we emphasized in our article, is to establish a uniform, accepted protocol for the preoperative evaluation of these patients and for assessment of pancreaticoduodenectomy specimens. This will facilitate not only comparison among studies but also the multi-institutional efforts needed to make progress in the treatment of this devastating disease. Ioannis T. Konstantinidis, MD Cristina R. Ferrone, MD Department of Surgery Massachusetts General Hospital Boston, MA [email protected]

REFERENCES 1. Campbell F, Smith RA, Whelan P, et al. Classification of R1 resections for pancreatic cancer: the prognostic relevance of tumour involvement within 1 mm of a resection margin. Histopathology. 2009;55:277–283. 2. Konstantinidis IT, Warshaw AL, Allen JN. Pancreatic ductal adenocarcinoma: is there a survival difference for r1 resections versus locally advanced unresectable tumors? What is a “true” R0 resection? Ann Surg. 2013;257:731–736.

Disclosure: None of the authors has any conflict of interest or source of funding relevant to this article to declare. DOI: 10.1097/SLA.0000000000000417

Annals of Surgery r Volume 261, Number 3, March 2015

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