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Meta‐analysis of delayed gastric emptying after pylorus‐preserving versus pylorus‐resecting pancreatoduodenectomy. BJS 2018; 105: 339-349.

Published: 7th February 2018

Authors: U. Klaiber, P. Probst, O. Strobel, C. W. Michalski, C. Dörr‐Harim, M. K. Diener et al.

Background

Delayed gastric emptying (DGE) is a frequent complication after pylorus‐preserving pancreatoduodenectomy. Recent studies have suggested that resection of the pylorus is associated with decreased rates of DGE. However, superiority of pylorus‐resecting pancreatoduodenectomy was not shown in a recent RCT. This meta‐analysis summarized evidence of the effectiveness and safety of pylorus‐preserving compared with pylorus‐resecting pancreatoduodenectomy.

Method

RCTs and non‐randomized studies comparing outcomes of pylorus‐preserving and pylorus‐resecting pancreatoduodenectomy were searched systematically in MEDLINE, Web of Science and CENTRAL. Random‐effects meta‐analyses were performed and the results presented as weighted odds ratios (ORs) or mean differences with their corresponding 95 per cent confidence intervals. Subgroup analyses were performed to account for interstudy heterogeneity between RCTs and non‐randomized studies.

Results

Three RCTs and eight non‐randomized studies with a total of 992 patients were included. Quantitative synthesis across all studies showed superiority for pylorus‐resecting pancreatoduodenectomy regarding DGE (OR 2·71, 95 per cent c.i. 1·48 to 4·96; P = 0·001) and length of hospital stay (mean difference 3·26 (95 per cent c.i. −1·04 to 5·48) days; P = 0·004). Subgroup analyses including only RCTs showed no significant statistical differences between the two procedures regarding DGE, and for all other effectiveness and safety measures.

Conclusion

Pylorus‐resecting pancreatoduodenectomy is not superior to pylorus‐preserving pancreatoduodenectomy for reducing DGE or other relevant complications.

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2 Comments

Essa Aleassa

6 months ago

We read with interest the meta-analysis by Klaiber et al. (1) on delayed gastric emptying (DGE) after pancreatoduodenectomy. The authors compared pylorus preserving (PPPD) and pylorus resecting (PPRD) options and concluded that PRPD was not superior.

Klaiber and colleagues included 3 randomised controlled trials (RCTs) (2-4), as well as 6 retrospective and 2 prospective non-randomised studies in their meta-analysis for a sizeable population of 992 patients. Of interest to the reader was the fact that they then performed subgroup analysis. All 3 RCTs contained at least 100 patients (100,130,188) and all were powered to demonstrate a 20% difference in DGE rates (2-4). That said the rates of DGE used for PPPD and PRPD in the power calculations did vary at 30% vs. 10%, 32% vs. 12%, and 25% vs. 5% respectively (2-4).

Based on the traditional statistical methodology that indicated the importance of hierarchical quality of data with RCTs at the top of the pyramid, and that when well-designed adequately powered RCTs exist that they should take precedence in terms of quality of evidence (5), the readers are wondering why the authors included the non-randomised data when 3 adequately powered RCTs exist. The addition of 8 such studies changed the overall result from being no difference to favouring the PRPD technique. Although the conclusion stated that PRPD was not superior, the inclusion of the non-randomsied data, most of which was retrospective, is confusing.

Essa M. Aleassa
Gareth Morris-Stiff

Section of Hepato-Pancreato-Biliary Surgery
Digestive Disease and Surgery Institute
Cleveland Clinic Foundation
Cleveland, OH
USA
e.aleassa@gmail.com 

References:
1. Klaiber U, Probst P, Strobel O, Michalski CW, Dorr-Harim C, Diener MK, Buchler MW, Hackert T. Meta-analysis of delayed gastric emptying after pylorus-preserving versus pylorus-resecting pancreatoduodenectomy. Br J Surg 2018;105(4): 339-349.
2. Hackert T, Probst P, Knebel P, Doerr-Harim C, Bruckner T, Klaiber U, Werner J, Schneider L, Michalski CW, Strobel O, Ulrich A, Diener MK, Buchler MW. Pylorus Resection Does Not Reduce Delayed Gastric Emptying After Partial Pancreatoduodenectomy: A Blinded Randomized Controlled Trial (PROPP Study, DRKS00004191). Ann Surg 2018;267(6): 1021-1027.
3. Kawai M, Tani M, Hirono S, Miyazawa M, Shimizu A, Uchiyama K, Yamaue H. Pylorus ring resection reduces delayed gastric emptying in patients undergoing pancreatoduodenectomy: a prospective, randomized, controlled trial of pylorus-resecting versus pylorus-preserving pancreatoduodenectomy. Ann Surg 2011;253(3): 495-501.
4. Matsumoto I, Shinzeki M, Asari S, Goto T, Shirakawa S, Ajiki T, Fukumoto T, Suzuki Y, Ku Y. A prospective randomized comparison between pylorus- and subtotal stomach-preserving pancreatoduodenectomy on postoperative delayed gastric emptying occurrence and long-term nutritional status. J Surg Oncol 2014;109(7): 690-696.
5. Sackett DL RW, Rosenberg WM, Haynes RB. Evidence Based Medicine: How to practice and teach EBM. Churchill Livingstone: New York, 1997.

    Thilo Hackert

    5 months ago

    We thank Dr Aleassa and Dr Morris-Stiff for their interest in our work and their comment. Indeed, the meta-analysis of three well designed RCTs including a total of 418 patients yields a powerful and robust result, which outweighs the result from any non-randomized study, especially those including only retrospective data. However, the aim of our study was to thoroughly summarize the existing evidence of the effectiveness and safety of pylorus-preserving compared with pylorus-resecting pancreatoduodenectomy and therefore, not only existing RCTs but also non-randomized trials comparing both procedures were included in the qualitative and quantitative analysis. Importantly, as a result of the inclusion of both randomized and non-randomized comparative trials, we clearly demonstrated how methodological limitations resulting from the study design can bias trial results leading to an overestimation of treatment effects. From a chronological point of view, it was not the addition of the non-randomized studies published between 2007 and 2015 that changed the result towards the superiority of pylorus resection, but the high-quality RCTs published between 2011 and 2017. The meta-analysis of this RCT subgroup proves that there was no superiority of pylorus resection with regard to DGE and other outcomes. In addition, the confirmation of the results from the only blinded and so far largest RCT (1) by our meta-analysis shows how worthwhile it is to overcome the methodological challenges of comparative trials in the evaluation of surgical interventions (2), which should encourage surgeons to design and conduct such trials.

    Ulla Klaiber
    Thilo Hackert

    Dept of General, Visceral and Transplantation Surgery
    University of Heidelberg
    Germany
    thilo_hackert@med.uni-heidelberg.de

    References:
    1. Hackert T, Probst P, Knebel P, Doerr-Harim C, Bruckner T, Klaiber U, et al. Pylorus Resection Does Not Reduce Delayed Gastric Emptying After Partial Pancreatoduodenectomy: A Blinded Randomized Controlled Trial (PROPP Study, DRKS00004191). Annals of surgery. 2017.
    2. Farrokhyar F, Karanicolas PJ, Thoma A, Simunovic M, Bhandari M, Devereaux PJ, et al. Randomized controlled trials of surgical interventions. Annals of surgery. 2010;251(3):409-16.