Letters to the Editors Survival calculations
4. Gudjonsson B. Survival statistics gone awry: Pancreatic cancer a case in point. J Clin Gastroenterol 2002;35:180-4. http://dx.doi.org/10.1016/j.surg.2014.06.004
To the Editors: I am afraid I made a serious oversight in my first Letter to the Editors (Surgery 2013;154:645) regarding the paper by Ferrone et al,1 but it is mainly serious for the authors. In my bewilderment when I saw their figures, I stated in the letter that their study ended in 2010. I was wrong, it is clearly stated that their study ended 2006. The study therefore covers only 3 more years than the period from 1978 to 2003 reported by Drs Willett2 and Domingez3 and they seem to report on all resections and survivors in from those years. The survivors are no more than 42 over those 28 years or 1.5 per year! How 53 additional survivors can be ‘‘produced’’ in those 3 additional years from 2003 to 2006 or 17.6 per year---needs to be explained further. Dr Ferrone is wrong regarding the paper by Dr Willett et al in stating that it ‘‘is not relevant because the article discusses the survival of unresected patients treated with intraoperative radiation.’’ The paper clearly reports on the ‘‘clinical course of 72 patients undergoing resection of the carcinoma of the head of pancreas.’’ Intraoperative radiation is mentioned as a possibility ‘‘at the time of resection.’’ There is no mention of unresectable patients. This should be easily ascertained; 1 author contributes to all 3 papers and 3 authors to 2 papers. These eminent authors confuse actual and actuarial survival as indicated with the Kaplan-Meier survival curve.4 As a consolation, I fully agree with the title of their paper1! I emphasize my previous comments and think the authors have to revise their paper, clarify, and then perhaps republish.
In response to Birgir Gudjonsson, MD
To the Editors: We appreciate and share the concern of Dr Gudjonsson that published data, from our institution or any other, be accurate. First, our GI pathologists have meticulously reviewed all of our published cases of longterm survivors to ensure that they were indeed pancreatic adenocarcinomas. Second, in response to his query, we have reviewed our primary survival data: The numbers of actual and projected 5-year survivors after resection are correct as reported. Kaplan-Meier curves are an accepted method of evaluating survival statistics as long as the numbers of observations suffice. Our statisticians confirm the validity of the Kaplan-Meier method and its application to our data. With regard to his prior concern about what he perceives as unlikely discrepancies in the numbers of patients reported in our several publications, those papers reported on different data sets (intraoperative radiation therapy vs resection for possible cure) at different time periods. In recent years, the numbers of patients undergoing pancreaticoduodenectomy for possible cure of pancreatic adenocarcinoma at the Massachusetts General Hospital has greatly increased, more than tripling in the last 20 years, the time period under discussion. The result is that the incidence of long-term survivors has significantly increased at an accelerating rate. Andrew L. Warshaw, MD Cristina R. Ferrone, MD Carlos Fernandez-Del Castillo, MD From the Department of Surgery Massachusetts General Hospital, 55 Fruit Street Boston, MA 02114 E-mail: [email protected]
Birgir Gudjonsson, MD, MACP, FRCP, AGAF From The Medical Clinic Reykjavik, Iceland E-mail: [email protected]
http://dx.doi.org/10.1016/j.surg.2014.06.005
References 1. Ferrone CR, Pieretti-Vanmarcke R, Bloom JP, Zheng H, Szymonifka J, Wargo JA, et al. Pancreatic ductal adenocarcinoma: long-term survival does not equal cure. Surgery 2012;152:S43-9. 2. Willett CG, Lewandrowski K, Warshaw AL, Efird J, Compton CC. Resection margins in carcinoma of the head of the pancreas. Implications for radiation therapy. Ann Surg 1993;217:144-8. 3. Dominguez I, Crippa S, Thayer SP, Hung YP, Ferrone CR, Warshaw AL, et al. Preoperative platelet count and survival prognosis in resected pancreatic ductal adenocarcinoma. World J Surg 2008;32:1051-6.
1286 SURGERY
Stetho-hammer: A not-so-novel aid in the neurologic examination
To the Editors: To elicit deep tendon reflexes, the tendon hammer is, and has been, the instrument of choice for medical student and clinicians alike, but its use---albeit reliable---poses a few challenges in everyday practice. The size and lack of portability of a tendon hammer means it is often not carried by doctors and, consequently, when required, it is often difficult to find. We propose the ‘‘Stetho-hammer.’’
4. Gudjonsson B. Survival statistics gone awry: Pancreatic cancer a case in point. J Clin Gastroenterol 2002;35:180-4. http://dx.doi.org/10.1016/j.surg.2014.06.004
To the Editors: I am afraid I made a serious oversight in my first Letter to the Editors (Surgery 2013;154:645) regarding the paper by Ferrone et al,1 but it is mainly serious for the authors. In my bewilderment when I saw their figures, I stated in the letter that their study ended in 2010. I was wrong, it is clearly stated that their study ended 2006. The study therefore covers only 3 more years than the period from 1978 to 2003 reported by Drs Willett2 and Domingez3 and they seem to report on all resections and survivors in from those years. The survivors are no more than 42 over those 28 years or 1.5 per year! How 53 additional survivors can be ‘‘produced’’ in those 3 additional years from 2003 to 2006 or 17.6 per year---needs to be explained further. Dr Ferrone is wrong regarding the paper by Dr Willett et al in stating that it ‘‘is not relevant because the article discusses the survival of unresected patients treated with intraoperative radiation.’’ The paper clearly reports on the ‘‘clinical course of 72 patients undergoing resection of the carcinoma of the head of pancreas.’’ Intraoperative radiation is mentioned as a possibility ‘‘at the time of resection.’’ There is no mention of unresectable patients. This should be easily ascertained; 1 author contributes to all 3 papers and 3 authors to 2 papers. These eminent authors confuse actual and actuarial survival as indicated with the Kaplan-Meier survival curve.4 As a consolation, I fully agree with the title of their paper1! I emphasize my previous comments and think the authors have to revise their paper, clarify, and then perhaps republish.
In response to Birgir Gudjonsson, MD
To the Editors: We appreciate and share the concern of Dr Gudjonsson that published data, from our institution or any other, be accurate. First, our GI pathologists have meticulously reviewed all of our published cases of longterm survivors to ensure that they were indeed pancreatic adenocarcinomas. Second, in response to his query, we have reviewed our primary survival data: The numbers of actual and projected 5-year survivors after resection are correct as reported. Kaplan-Meier curves are an accepted method of evaluating survival statistics as long as the numbers of observations suffice. Our statisticians confirm the validity of the Kaplan-Meier method and its application to our data. With regard to his prior concern about what he perceives as unlikely discrepancies in the numbers of patients reported in our several publications, those papers reported on different data sets (intraoperative radiation therapy vs resection for possible cure) at different time periods. In recent years, the numbers of patients undergoing pancreaticoduodenectomy for possible cure of pancreatic adenocarcinoma at the Massachusetts General Hospital has greatly increased, more than tripling in the last 20 years, the time period under discussion. The result is that the incidence of long-term survivors has significantly increased at an accelerating rate. Andrew L. Warshaw, MD Cristina R. Ferrone, MD Carlos Fernandez-Del Castillo, MD From the Department of Surgery Massachusetts General Hospital, 55 Fruit Street Boston, MA 02114 E-mail: [email protected]
Birgir Gudjonsson, MD, MACP, FRCP, AGAF From The Medical Clinic Reykjavik, Iceland E-mail: [email protected]
http://dx.doi.org/10.1016/j.surg.2014.06.005
References 1. Ferrone CR, Pieretti-Vanmarcke R, Bloom JP, Zheng H, Szymonifka J, Wargo JA, et al. Pancreatic ductal adenocarcinoma: long-term survival does not equal cure. Surgery 2012;152:S43-9. 2. Willett CG, Lewandrowski K, Warshaw AL, Efird J, Compton CC. Resection margins in carcinoma of the head of the pancreas. Implications for radiation therapy. Ann Surg 1993;217:144-8. 3. Dominguez I, Crippa S, Thayer SP, Hung YP, Ferrone CR, Warshaw AL, et al. Preoperative platelet count and survival prognosis in resected pancreatic ductal adenocarcinoma. World J Surg 2008;32:1051-6.
1286 SURGERY
Stetho-hammer: A not-so-novel aid in the neurologic examination
To the Editors: To elicit deep tendon reflexes, the tendon hammer is, and has been, the instrument of choice for medical student and clinicians alike, but its use---albeit reliable---poses a few challenges in everyday practice. The size and lack of portability of a tendon hammer means it is often not carried by doctors and, consequently, when required, it is often difficult to find. We propose the ‘‘Stetho-hammer.’’
