Time to Prioritise Quality Over Quantity in Prehabilitation Trials: A Literature Review
The increasing number of prehabilitation randomised controlled trials (RCTs) for cancer surgery patients emphasises the need for high-quality evidence. Therefore, this study aims to assess reporting quality and risk of bias in prehabilitation RCTs. A comprehensive search was conducted across multiple databases, including MEDLINE, Embase, The Cochrane Library, CINAHL, AMED, and PsycINFO to identify RCTs evaluating the effectiveness of exercise, nutrition, and/or psychological interventions on postoperative complications and/or length of hospital stay in adult patients undergoing cancer surgery. Trials were assessed for risk of bias, reporting quality and other relevant metrics.
Of the 74 included RCTs, 55 had a high risk of bias. Deviations from intended interventions (55%) and missing outcome data (32%) were the most frequently identified items with a high risk of bias. Only nine of 13 TIDieR items were adequately reported, and just nine RCTs provided information on intervention modifications. 55% of trials provided a protocol, with 68% altering primary and/or secondary aims.
Prehabilitation RCTs exhibit poor reporting quality and high risk of bias. More transparent trials are needed to assess the effectiveness of prehabilitation programs. Identifying barriers to improving the quality would assist in enhancing the reliability of future trials.
1. Wynter-Blyth V, Moorthy K. Prehabilitation: preparing patients for surgery. BMJ. 2017;358.
2. Durrand J, Singh SJ, Danjoux G. Prehabilitation. Clin Med (Lond). 2019;19(6):458-64.
3. Waterland JL, McCourt O, Edbrooke L, Granger CL, Ismail H, Riedel B, et al. Efficacy of Prehabilitation Including Exercise on Postoperative Outcomes Following Abdominal Cancer Surgery: A Systematic Review and Meta-Analysis. Frontiers in Surgery. 2021;8.
4. Banugo P, Amoako D. Prehabilitation. BJA Education. 2017;17(12):401-5.
5. Government US. PMC Full-Text Search Results United States2011 [updated 2011; cited 2022 December 20 2022]. Available from: https://www.ncbi.nlm.nih.gov/pmc.
6. Kluwer W. Ovid Netherlands: Wolters Kluwer 2022 [updated December 19 2022; cited 2022 21 December 2022]. Available from: https://ovidsp-dc1-ovid-com.ezproxy.uws.edu.au/ovida/ovidweb.cgi.
7. Cuijpers ACM, Linskens FG, Bongers BC, Stassen LPS, Lubbers T, van Meeteren NLU. Quality and clinical generalizability of feasibility outcomes in exercise prehabilitation before colorectal cancer surgery – A systematic review. European Journal of Surgical Oncology. 2022;48(7):1483-97.
8. Thabane L, Ma J, Chu R, Cheng J, Ismaila A, Rios LP, et al. A tutorial on pilot studies: the what, why and how. BMC Medical Research Methodology. 2010;10(1):1.
9. Eldridge SM, Chan CL, Campbell MJ, Bond CM, Hopewell S, Thabane L, et al. CONSORT 2010 statement: extension to randomised pilot and feasibility trials. BMJ. 2016;355:i5239.
10. Elliott L, Coulman K, Blencowe NS, Qureshi MI, Lee KS, Hinchliffe RJ, et al. A systematic review of reporting quality for anaesthetic interventions in randomised controlled trials. Anaesthesia. 2021;76(6):832-6.
11. Janackovic K, Puljak L. Reporting quality of randomized controlled trial abstracts in the seven highest-ranking anesthesiology journals. Trials. 2018;19(1):591. 12. Yu J, Yang Z, Zhang Y, Cui Y, Tang J, Hirst A, et al. The methodological quality of surgical randomized controlled trials: A cross-sectional systemic review. Asian Journal of Surgery. 2022;45(10):1817-22.
13. Gurusamy KS, Gluud C, Nikolova D, Davidson BR. Assessment of risk of bias in randomized clinical trials in surgery. Br J Surg. 2009;96(4):342-9.
14. Jarry C, Valera L, Navarro F, Cerda J, Grasset E, Gabrielli M. Research in surgery: The adversities that every surgeon should know and face. Health Sciences Review. 2022;2:100016.
15. Rangel SJ, Kelsey J, Colby CE, Anderson J, Moss RL. Development of a quality assessment scale for retrospective clinical studies in pediatric surgery. J Pediatr Surg. 2003;38(3):390-6; discussion -6.
16. Chalmers I, Glasziou P. Avoidable waste in the production and reporting of research evidence. Lancet. 2009;374(9683):86-9.
17. Sterne JAC, Savović J, Page MJ, Elbers RG, Blencowe NS, Boutron I, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366:l4898.
18. Higgins J.P.T. TJ, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.32022 February 2022.
19. Aromataris E MZE. JBI Manual for Evidence Synthesis: JBI; 2020 [Available from: https://synthesismanual.jbi.global. https:// doi.org/10.46658/JBIMES-20-01.
20. Covidence. Melbourne, Australia: Veritas Health Innovation.
21. Hoffmann TC, Glasziou PP, Boutron I, Milne R, Perera R, Moher D, et al. Better reporting of interventions: template for intervention description and replication (TIDieR) checklist and guide. Bmj. 2014;348:g1687.
22. Aiko S, Kumano I, Yamanaka N, Tsujimoto H, Takahata R, Maehara T. Effects of an immuno-enhanced diet containing antioxidants in esophageal cancer surgery following neoadjuvant therapy. Dis Esophagus. 2012;25(2):137-45.
23. Amraoui J, Pouliquen C, Fraisse J, Dubourdieu J, Rey Dit Guzer S, Leclerc G, et al. Effects of a Hypnosis Session Before General Anesthesia on Postoperative Outcomes in Patients Who Underwent Minor Breast Cancer Surgery: The HYPNOSEIN Randomized Clinical Trial. JAMA Netw Open. 2018;1(4):e181164.
24. Ashida R, Okamura Y, Wakabayashi-Nakao K, Mizuno T, Aoki S, Uesaka K. The Impact of Preoperative Enteral Nutrition Enriched with Eicosapentaenoic Acid on Postoperative Hypercytokinemia after Pancreatoduodenectomy: The Results of a Double-Blinded Randomized Controlled Trial. Dig Surg. 2019;36(4):348-56.
25. Ausania F, Senra P, Meléndez R, Caballeiro R, Ouviña R, CasalNúñez E. Prehabilitation in patients undergoing pancreaticoduodenectomy: a randomized controlled trial. Rev Esp Enferm Dig. 2019;111(8):603-8.
26. Banerjee S, Manley K, Shaw B, Lewis L, Cucato G, Mills R, et al. Vigorous intensity aerobic interval exercise in bladder cancer patients prior to radical cystectomy: a feasibility randomised controlled trial. Support Care Cancer. 2018;26(5):1515-23.
27. Bartels M, Biesalski HK, Engelhart K, Sendlhofer G, Rehak P, Nagel E. Pilot study on the effect of parenteral vitamin E on ischemia and reperfusion induced liver injury: a double blind, randomized, placebo-controlled trial. Clin Nutr. 2004;23(6):1360-70.
28. Barth RJ, Jr., Mills JB, Suriawinata AA, Putra J, Tosteson TD, Axelrod D, et al. Short-term Preoperative Diet Decreases Bleeding After Partial Hepatectomy: Results From a Multi-institutional Randomized Controlled Trial. Ann Surg. 2019;269(1):48-52.
29. Benzo R, Wigle D, Novotny P, Wetzstein M, Nichols F, Shen RK, et al. Preoperative pulmonary rehabilitation before lung cancer resection: results from two randomized studies. Lung Cancer. 2011;74(3):441-5.
30. Blackwell JEM, Doleman B, Boereboom CL, Morton A, Williams S, Atherton P, et al. High-intensity interval training produces a significant improvement in fitness in less than 31 days before surgery for urological cancer: a randomised control trial. Prostate Cancer Prostatic Dis. 2020;23(4):696-704.
31. Braga M, Bissolati M, Rocchetti S, Beneduce A, Pecorelli N, Di Carlo V. Oral preoperative antioxidants in pancreatic surgery: a double-blind, randomized, clinical trial. Nutrition. 2012;28(2):160-4.
32. Braga M, Gianotti L, Vignali A, Carlo VD. Preoperative oral arginine and n-3 fatty acid supplementation improves the immunometabolic host response and outcome after colorectal resection for cancer. Surgery. 2002;132(5):805-14.
33. Burden ST, Gibson DJ, Lal S, Hill J, Pilling M, Soop M, et al. Pre-operative oral nutritional supplementation with dietary advice versus dietary advice alone in weight-losing patients with colorectal cancer: single-blind randomized controlled trial. J Cachexia Sarcopenia Muscle. 2017;8(3):437-46.
34. Burden ST, Hill J, Shaffer JL, Campbell M, Todd C. An unblinded randomised controlled trial of preoperative oral supplements in colorectal cancer patients. J Hum Nutr Diet. 2011;24(5):441-8.
35. Chen H, Pan D, Li L-q. The effects of multi-oil fat emulsion on older patients with gastric cancer. Biomedical Research-tokyo. 2017;28:4270-6.
36. Christensen JF, Simonsen C, Banck-Petersen A, Thorsen-Streit S, Herrstedt A, Djurhuus SS, et al. Safety and feasibility of preoperative exercise training during neoadjuvant treatment before surgery for adenocarcinoma of the gastro-oesophageal junction. BJS Open. 2019;3(1):74-84.
37. de Miranda Torrinhas RS, Santana R, Garcia T, Cury-Boaventura MF, Sales MM, Curi R, et al. Parenteral fish oil as a pharmacological agent to modulate post-operative immune response: a randomized, double-blind, and controlled clinical trial in patients with gastrointestinal cancer. Clin Nutr. 2013;32(4):503-10.
38. Dettling DS, van der Schaaf M, Blom RL, Nollet F, Busch OR, van Berge Henegouwen MI. Feasibility and effectiveness of pre-operative inspiratory muscle training in patients undergoing oesophagectomy: a pilot study. Physiother Res Int. 2013;18(1):16-26.
39. Dronkers JJ, Lamberts H, Reutelingsperger IM, Naber RH, Dronkers-Landman CM, Veldman A, et al. Preoperative therapeutic programme for elderly patients scheduled for elective abdominal oncological surgery: a randomized controlled pilot study. Clin Rehabil. 2010;24(7):614-22.
40. Dunne DF, Jack S, Jones RP, Jones L, Lythgoe DT, Malik HZ, et al. Randomized clinical trial of prehabilitation before planned liver resection. Br J Surg. 2016;103(5):504-12.
41. Fan ST, Lau WY, Wong KK, Chan YP. Pre-operative parenteral nutrition in patients with oesophageal cancer: a prospective, randomised clinical trial. Clin Nutr. 1989;8(1):23-7.
42. Fang Y-n, Zhao Q, Huang D, Guan S, Lv J, editors. Effects of Exercise Training on Surgery Tolerability in Lung Cancer Patients with Impaired Pulmonary Function2013.
43. Fujitani K, Tsujinaka T, Fujita J, Miyashiro I, Imamura H, Kimura Y, et al. Prospective randomized trial of preoperative enteral immunonutrition followed by elective total gastrectomy for gastric cancer. Br J Surg. 2012;99(5):621-9.
44. Giger-Pabst U, Lange J, Maurer C, Bucher C, Schreiber V, Schlumpf R, et al. Short-term preoperative supplementation of an immunoenriched diet does not improve clinical outcome in well-nourished patients undergoing abdominal cancer surgery. Nutrition. 2013;29(5):724-9.
45. Gil MJ, Franch G, Guirao X, Oliva A, Herms R, Salas E, et al. Response of severely malnourished patients to preoperative parenteral nutrition: a randomized clinical trial of water and sodium restriction. Nutrition. 1997;13(1):26-31.
46. Gunerhan Y, Koksal N, Sahin UY, Uzun MA, Ekşioglu-Demiralp E. Effect of preoperative immunonutrition and other nutrition models on cellular immune parameters. World J Gastroenterol. 2009;15(4):467-72.
47. Hamamoto H, Yamamoto M, Masubuchi S, Ishii M, Osumi W, Tanaka K, et al. The impact of preoperative carbohydrate loading on intraoperative body temperature: a randomized controlled clinical trial. Surg Endosc. 2018;32(11):4393-401.
48. Hogan S, Solomon M, Rangan A, Ferrie S, Carey S. The Impact of Preoperative Immunonutrition and Standard Polymeric Supplements on Patient Outcomes After Pelvic Exenteration Surgery, Taking Compliance Into Consideration: A Randomized Controlled Trial. JPEN J Parenter Enteral Nutr. 2020;44(5):806-14.
49. Horvat M, Krebs B, Potrc S, Ivanecz A, Kompan L. Preoperative synbiotic bowel conditioning for elective colorectal surgery. Wien Klin Wochenschr. 2010;122 Suppl 2:26-30.
50. Huang J, Lai Y, Gao K, Wang Y, Du H, Su J, et al. Surfactant Protein-D: A sensitive predictor for efficiency of preoperative pulmonary rehabilitation. Int J Surg. 2017;41:136-42.
51. Huang J, Lai Y, Zhou X, Li S, Su J, Yang M, et al. Short-term high-intensity rehabilitation in radically treated lung cancer: a three-armed randomized controlled trial. J Thorac Dis. 2017;9(7):1919-29.
52. Jin D, Phillips M, Byles JE. Effects of parenteral nutrition support and chemotherapy on the phasic composition of tumor cells in gastrointestinal cancer. JPEN J Parenter Enteral Nutr. 1999;23(4):237-41.
53. Kabata P, Jastrzębski T, Kąkol M, Król K, Bobowicz M, Kosowska A, et al. Preoperative nutritional support in cancer patients with no clinical signs of malnutrition--prospective randomized controlled trial. Support Care Cancer. 2015;23(2):365-70.
54. Karlsson E, Farahnak P, Franzén E, Nygren-Bonnier M, Dronkers J, van Meeteren N, et al. Feasibility of preoperative supervised home-based exercise in older adults undergoing colorectal cancer surgery - A randomized controlled design. PLoS ONE. 2019;14(7):e0219158.
55. Kaya SO, Akcam TI, Ceylan KC, Samancılar O, Ozturk O, Usluer O. Is preoperative protein-rich nutrition effective on postoperative outcome in non-small cell lung cancer surgery? A prospective randomized study. J Cardiothorac Surg. 2016;11:14.
56. Kikuchi Y, Hiroshima Y, Matsuo K, Kawaguchi D, Murakami T,Yabushita Y, et al. A Randomized Clinical Trial of Preoperative Administration of Branched-Chain Amino Acids to Prevent Postoperative Ascites in Patients with Liver Resection for Hepatocellular Carcinoma. Ann Surg Oncol. 2016;23(11):3727-35.
57. Kitagawa H, Namikawa T, Yatabe T, Munekage M, Yamasaki F, Kobayashi M, et al. Effects of a preoperative immune-modulating diet in patients with esophageal cancer: a prospective parallel group randomized study. Langenbecks Arch Surg. 2017;402(3):531-8.
58. Koet LL, Kraima A, Derksen I, Lamme B, Belt EJT, van Rosmalen J, et al. Effectiveness of preoperative group education for patients with colorectal cancer: managing expectations. Support Care Cancer. 2021;29(9):5263-71.
59. Lai Y, Huang J, Yang M, Su J, Liu J, Che G. Seven-day intensive preoperative rehabilitation for elderly patients with lung cancer: a randomized controlled trial. J Surg Res. 2017;209:30-6.
60. Lai Y, Su J, Qiu P, Wang M, Zhou K, Tang Y, et al. Systematic short-term pulmonary rehabilitation before lung cancer lobectomy: a randomized trial. Interact Cardiovasc Thorac Surg. 2017;25(3):476-83.
61. Lai Y, Wang X, Zhou K, Su J, Che G. Impact of one-week preoperative physical training on clinical outcomes of surgical lung cancer patients with limited lung function: a randomized trial. Ann Transl Med. 2019;7(20):544.
62. Licker M, Karenovics W, Diaper J, Frésard I, Triponez F, Ellenberger C, et al. Short-Term Preoperative High-Intensity Interval Training in Patients Awaiting Lung Cancer Surgery: A Randomized Controlled Trial. J Thorac Oncol. 2017;12(2):323-33.
63. Liu Z, Qiu T, Pei L, Zhang Y, Xu L, Cui Y, et al. Two-Week Multimodal Prehabilitation Program Improves Perioperative Functional Capability in Patients Undergoing Thoracoscopic Lobectomy for Lung Cancer: A Randomized Controlled Trial. Anesth Analg. 2020;131(3):840-9.
64. López-Rodríguez-Arias F, Sánchez-Guillén L, Aranaz-Ostáriz V, Triguero-Cánovas D, Lario-Pérez S, Barber-Valles X, et al. Effect of home-based prehabilitation in an enhanced recovery after surgery program for patients undergoing colorectal cancer surgery during the COVID-19 pandemic. Support Care Cancer. 2021;29(12):7785-91.
65. Manzanares Campillo MDC, Martín Fernández J, Amo Salas M, Casanova Rituerto D. [A randomized controlled trial of preoperative oral immunonutrition in patients undergoing surgery for colorectal cancer: hospital stay and health care costs]. Cir Cir. 2017;85(5):393-400.
66. McCarter MD, Gentilini OD, Gomez ME, Daly JM. Preoperative oral supplement with immunonutrients in cancer patients. JPEN J Parenter Enteral Nutr. 1998;22(4):206-11.
67. Mikagi K, Kawahara R, Kinoshita H, Aoyagi S. Effect of preoperative immunonutrition in patients undergoing hepatectomy; a randomized controlled trial. Kurume Med J. 2011;58(1):1-8.
68. Minnella EM, Awasthi R, Bousquet-Dion G, Ferreira V, Austin B, Audi C, et al. Multimodal Prehabilitation to Enhance Functional Capacity Following Radical Cystectomy: A Randomized Controlled Trial. Eur Urol Focus. 2021;7(1):132-8.
69. Minnella EM, Awasthi R, Loiselle SE, Agnihotram RV, Ferri LE, Carli F. Effect of Exercise and Nutrition Prehabilitation on Functional Capacity in Esophagogastric Cancer Surgery: A Randomized Clinical Trial. JAMA Surg. 2018;153(12):1081-9.
70. Minnella EM, Ferreira V, Awasthi R, Charlebois P, Stein B, Liberman AS, et al. Effect of two different pre-operative exercise training regimens before colorectal surgery on functional capacity: A randomised controlled trial. Eur J Anaesthesiol. 2020;37(11):969-78.
71. Morano MT, Araújo AS, Nascimento FB, da Silva GF, Mesquita R, Pinto JS, et al. Preoperative pulmonary rehabilitation versus chest physical therapy in patients undergoing lung cancer resection: a pilot randomized controlled trial. Arch Phys Med Rehabil. 2013;94(1):53-8.
72. Moriya T. Effects of Preoperative Use of an Immune-Enhancing Diet on Postoperative Complications and Long-Term Outcome: A Randomized Clinical Trial in Colorectal Cancer Surgery in Japanese Patients. Gastroenterology and Hepatology. 2015;2:1-8.
73. Moug SJ, Mutrie N, Barry SJE, Mackay G, Steele RJC, Boachie C, et al. Prehabilitation is feasible in patients with rectal cancer undergoing neoadjuvant chemoradiotherapy and may minimize physical deterioration: results from the REx trial. Colorectal Dis. 2019;21(5):548-62.
74. Müller JM, Brenner U, Dienst C, Pichlmaier H. Preoperative parenteral feeding in patients with gastrointestinal carcinoma. Lancet. 1982;1(8263):68-71.
75. Nakamura K, Kariyazono H, Komokata T, Hamada N, Sakata R, Yamada K. Influence of preoperative administration of omega-3 fatty acid-enriched supplement on inflammatory and immune responses in patients undergoing major surgery for cancer. Nutrition. 2005;21(6):639-49.
76. Okamoto Y, Okano K, Izuishi K, Usuki H, Wakabayashi H, Suzuki Y. Attenuation of the systemic inflammatory response and infectious complications after gastrectomy with preoperative oral arginine and omega-3 fatty acids supplemented immunonutrition. World J Surg. 2009;33(9):1815-21.
77. Özdemir İ A, Comba C, Demirayak G, Gülseren V, Erdogan SV, Aslanova F, et al. Impact of pre-operative walking on postoperative bowel function in patients with gynecologic cancer. Int J Gynecol Cancer. 2019;29(8):1311-6.
78. Pehlivan E, Turna A, Gurses A, Gurses HN. The effects of preoperative short-term intense physical therapy in lung cancer patients: a randomized controlled trial. Ann Thorac Cardiovasc Surg. 2011;17(5):461-8.
79. Pexe-Machado PA, de Oliveira BD, Dock-Nascimento DB, de Aguilar-Nascimento JE. Shrinking preoperative fast time with maltodextrin and protein hydrolysate in gastrointestinal resections due to cancer. Nutrition. 2013;29(7-8):1054-9.
80. Polakowski CB, Kato M, Preti VB, Schieferdecker MEM, Ligocki Campos AC. Impact of the preoperative use of synbiotics in colorectal cancer patients: A prospective, randomized, double-blind, placebo-controlled study. Nutrition. 2019;58:40-6.
81. Reis PGA, Polakowski C, Lopes M, Bussyguin DS, Ferreira RP, Preti VB, et al. Abbreviated preoperative fasting favours postoperative oral intake at lower hospital admission costs for cancer patients. Rev Col Bras Cir. 2019;46(3):e20192175.
82. Rizvanović N, Nesek Adam V, Čaušević S, Dervišević S, Delibegović S. A randomised controlled study of preoperative oral carbohydrate loading versus fasting in patients undergoing colorectal surgery. Int J Colorectal Dis. 2019;34(9):1551-61.
83. Rovera L GB, C. ALLTAuDy, M.R. ALOP, G. BUFF,COCIMANO M. T. CAPALDP, O. PACE. Utilità di un supporto nutrizionale preoperatorio in pazienti affetti da carcinoma vescicale Rivista Italiana dì Nutrizione Parenterale ed Enterale 1989;7:79-85.
84. Russell K, Zhang HG, Gillanders LK, Bartlett AS, Fisk HL, Calder PC, et al. Preoperative immunonutrition in patients undergoing liver resection: A prospective randomized trial. World J Hepatol. 2019;11(3):305-17.
85. Santa Mina D, Hilton WJ, Matthew AG, Awasthi R, BousquetDion G, Alibhai SMH, et al. Prehabilitation for radical prostatectomy: A multicentre randomized controlled trial. Surg Oncol. 2018;27(2):289-98.
86. Sebio García R, Yáñez-Brage MI, Giménez Moolhuyzen E, Salorio Riobo M, Lista Paz A, Borro Mate JM. Preoperative exercise training prevents functional decline after lung resection surgery: a randomized, single-blind controlled trial. Clin Rehabil. 2017;31(8):1057-67.
87. Shukla A, Granger CL, Wright GM, Edbrooke L, Denehy L. Attitudes and Perceptions to Prehabilitation in Lung Cancer. Integr Cancer Ther. 2020;19:1534735420924466.
88. Steffens D, Young J, Beckenkamp PR, Ratcliffe J, Rubie F, Ansari N, et al. Feasibility and acceptability of a preoperative exercise program for patients undergoing major cancer surgery: results from a pilot randomized controlled trial. Pilot Feasibility Stud. 2021;7(1):27.
89. Uno H, Furukawa K, Suzuki D, Shimizu H, Ohtsuka M, Kato A, et al. Immunonutrition suppresses acute inflammatory responses through modulation of resolvin E1 in patients undergoing major hepatobiliary resection. Surgery. 2016;160(1):228-36.
90. Valkenet K, Trappenburg JCA, Ruurda JP, Guinan EM, Reynolds JV, Nafteux P, et al. Multicentre randomized clinical trial of inspiratory muscle training versus usual care before surgery for oesophageal cancer. Br J Surg. 2018;105(5):502-11.
91. van Adrichem EJ, Meulenbroek RL, Plukker JT, Groen H, van Weert E. Comparison of two preoperative inspiratory muscle training programs to prevent pulmonary complications in patients undergoing esophagectomy: a randomized controlled pilot study. Ann Surg Oncol. 2014;21(7):2353-60.
92. Wierdak M, Surmiak M, Milian-Ciesielska K, Rubinkiewicz M, Rzepa A, Wysocki M, et al. Immunonutrition Changes Inflammatory Response in Colorectal Cancer: Results from a Pilot Randomized Clinical Trial. Cancers (Basel). 2021;13(6).
93. Xu J, Zhong Y, Jing D, Wu Z. Preoperative enteral immunonutrition improves postoperative outcome in patients with gastrointestinal cancer. World J Surg. 2006;30(7):1284-9.
94. Yamana I, Takeno S, Hashimoto T, Maki K, Shibata R, Shiwaku H, et al. Randomized Controlled Study to Evaluate the Efficacy of a Preoperative Respiratory Rehabilitation Program to Prevent Postoperative Pulmonary Complications after Esophagectomy. Dig Surg. 2015;32(5):331-7.
95. Zelić M, Stimac D, Mendrila D, Tokmadžić VS, Fišić E, Uravić M, et al. Influence of preoperative oral feeding on stress response after resection for colon cancer. Hepatogastroenterology. 2012;59(117):1385-9.
96. L Rovera GR, C Alliaudi, MR Aloi, G Buffa, V Cocimano, MT Capaldi, O Pace. Usefulness of preoperative nutritional support in patients with bladder cancer. Rivista Italiana di Nutrizione Parenterale ed Enterale. 1989;7:79-85.
97. Roberts I, Ker K. How systematic reviews cause research waste. The Lancet. 2015;386(10003):1536.
98. Craig P, Dieppe P, Macintyre S, Michie S, Nazareth I, Petticrew M. Developing and evaluating complex interventions: the new Medical Research Council guidance. Bmj. 2008;337:a1655.
99. O'Cathain A, Croot L, Duncan E, Rousseau N, Sworn K, Turner KM, et al. Guidance on how to develop complex interventions to improve health and healthcare. BMJ Open. 2019;9(8):e029954.
100. Blencowe NS, Mills N, Cook JA, Donovan JL, Rogers CA, Whiting P, et al. Standardizing and monitoring the delivery of surgical interventions in randomized clinical trials. Br J Surg. 2016;103(10):1377-84.
101. Abbott JH. The Distinction Between Randomized Clinical Trials (RCTs) and Preliminary Feasibility and Pilot Studies: What They Are and Are Not. Journal of Orthopaedic & Sports Physical Therapy. 2014;44(8):555-8.
102. Sterne JA, Hernán MA, Reeves BC, Savović J, Berkman ND, Viswanathan M, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ. 2016;355:i4919.