STRENGTHS AND LIMITATIONS OF THIS STUDY

This study will compare the surgical outcomes of robotic pancreaticoduodenectomy with open or laparoscopic pancreaticoduodenectomy in patients with overweight or obesity.

A systematic literature search of multiple biomedical databases will be performed to ensure the inclusion of all pertinent randomised controlled trials and observational studies.

Since this study is a meta-analysis of the published data, the potential heterogeneity across included studies will influence the certainty of evidence.

Introduction

Pancreaticoduodenectomy is widely acknowledged as the standard surgical intervention for patients afflicted with both benign and malignant tumours situated in the periampullary region and pancreatic head.1–4 Despite significant advancements in pancreatic surgery in recent decades, pancreaticoduodenectomy remains a highly intricate and technically demanding gastrointestinal procedure associated with considerable morbidity and mortality.3 5 6 Although conventional open pancreaticoduodenectomy is a feasible surgical alternative, it is associated with increased trauma, a protracted postoperative recovery period, a heightened susceptibility to wound infection and an extended hospitalisation.7 8 The initial instance of laparoscopic pancreaticoduodenectomy was documented in 1994, and subsequently, minimally invasive pancreaticoduodenectomy has become increasingly favoured as a therapeutic approach for pancreatic and periampullary tumours.9 The introduction of the first robotic pancreaticoduodenectomy at the turn of the 21st century heralded a new era in the realm of less invasive pancreatic surgery.10 11 Robotic surgery presents numerous advantages compared with conventional open surgery or laparoscopic procedures, including improved visual perception in three dimensions with high definition, a more favourable ergonomic setting and enhanced instrument dexterity.4 12

In recent decades, the prevalence of obesity has escalated to epidemic proportions, with projections indicating that over one-third of the global population will be diagnosed with overweight or obesity by 2030.13 14 This alarming trend poses significant healthcare and socioeconomic challenges, particularly in light of the increasing occurrence of solid and haematological tumours associated with obesity.15–17 Recent epidemiological investigations have underscored the independent role of obesity as a risk factor for pancreatic and periampullary tumours.18–20 Notably, a five-unit increase in body mass index (BMI) has been associated with a more than 10% elevation in the likelihood of developing pancreatic tumours.21–24

It has been reported that obesity may lead to increased procedure-related complications in colorectal surgery, gastric surgery, ovarian surgery and pancreatic surgery.3 25–27 The occurrence of postoperative complications is disruptive as it can hinder the delivery of adjuvant chemotherapy and impact patient survival rates.28 Meta-analysis is an essential research method in evidence-based medicine, which presents high-quality evidence for clinical decision-making based on published aggregated data of two or more separate studies.29–32 Although there have been several published meta-analyses comparing perioperative outcomes of different surgical approaches for pancreaticoduodenectomy in all patients, the potential differences in surgical outcomes of these approaches have not been explored specifically in patients with obesity.2 33 34 The current lack of comprehensive assessment regarding the potential variances in surgical outcomes between robotic pancreaticoduodenectomy and open or laparoscopic pancreaticoduodenectomy in patients with overweight or obesity necessitates urgent attention.2 33 34 This issue assumes greater significance due to the simultaneous escalation of obesity and pancreatic tumour incidences.

There is a growing evidence that meta-analyses of randomised controlled trials (RCTs) and observational studies are more valuable than meta-analyses of RCTs alone.35 36 Compared with RCTs with highly selected patients, observational studies are likely to provide useful insight into small treatment effects in a more heterogeneous patient population.35 37–40 Given the relatively small number of RCTs due to its difficulty of execution in the surgical field, adding observational studies to a meta-analysis brings complementary evidence for health decision-making in surgical procedures.35 37–40 Consequently, we aim to undertake a meta-analysis encompassing all available RCTs and non-randomised comparative studies to appraise the immediate surgical outcomes of robotic pancreaticoduodenectomy in comparison to open or laparoscopic pancreaticoduodenectomy specifically in patients with overweight or obesity.

Methods and analysisStudy registration

This study (PROSPERO registration number: CRD42023462321) will be reported based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) statement guidelines.41 We are expecting to conduct the study from June to December 2024.

Inclusion criteria

We will set inclusion criteria according to the Participants, Intervention, Comparators, Outcomes and Study design principles.42 43 (1) Participants will be adults (≥18 years old) with overweight (BMI 25–29.9 kg/m2) or obesity (BMI≥30 kg/m2) undergoing pancreaticoduodenectomy for pancreatic and periampullary tumours. (2) Intervention will be robotic pancreaticoduodenectomy. (3) Comparators will include open pancreaticoduodenectomy and laparoscopic pancreaticoduodenectomy. (4) The primary outcomes in this study will be intraoperative estimated blood loss and the incidence of postoperative infection. The secondary outcomes will include operation time, the occurrence of intraoperative blood transfusion, severe complications, postoperative pancreatic fistula (POPF), postoperative haemorrhage, delayed gastric emptying (DGE), duration of hospitalisation and mortality. The Clavien-Dindo (CD) classification will be used to classify postoperative complications occurring within 30 days after surgery.44 Severe complications will be defined as the CD grade ≥3.44 POPF, postoperative haemorrhage and DGE will be defined using the International Study Group of Pancreatic Surgery classification.45–47 (5) Study designs will include RCTs, non-RCTs and cohort studies.

Exclusion criteria

Irrelevant literature that does not meet the PICOS requirements will be filtered. Animal experiments, reviews and case reports will be excluded. Moreover, studies with incomplete data or those with duplicate data will not be included.

Search strategy

Clinical studies that compare robotic pancreaticoduodenectomy with open or laparoscopic pancreaticoduodenectomy in patients with overweight or obesity will be potentially eligible for our study. Databases such as PubMed, Embase and the Cochrane Library will be used to conduct a systematic literature search. We will retrieve the English-language literature published from inception up to December 2024 through the subject words and keywords retrieval method using specific terms, such as pancreaticoduodenectomy, pancreatectomy, robotic, robot-assisted, da Vinci, open, laparotomy, laparoscopic, overweight, obesity, BMI, observational study, cohort studies, comparative study and RCT. The specific search strategies are described in online supplemental file 1. Moreover, reference lists of included studies and relevant reviews will be handsearched. Grey literature will not be retrieved because it is difficult to determine whether they have been assessed through peer review.48 49

Study selection and screening

According to the eligibility requirements, two separate reviewers will screen the title and abstract of all retrieved articles. After excluding the irrelevant literature, the remaining articles will be further scrutinised by full-text review. A third reviewer will resolve any dispute regarding literature eligibility. The results will be reported according to the PRISMA flow diagram, as indicated in figure 1.42

Figure 1

PRISMA flow diagram for the identification and selection of studies. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Data extraction

Two independent reviewers will complete the information extraction process using a prearranged form. The extracted data will include the authors’ name, publication year, country, study design, inclusion and exclusion criteria, sample size, subject characteristics (such as age, gender and BMI), surgical approach and perioperative outcomes of interest. Any disagreement during the data extraction process will be settled by consulting with a third reviewer.

Risk of bias assessment

The methodological quality of the included studies will be assessed by two independent reviewers. The Cochrane risk of bias tool will be used to evaluate the methodological quality of RCTs from the following aspects: random sequence, allocation concealment, blinding, outcome data and other bias.50 The Newcastle-Ottawa Scale (NOS) will be used for evaluating the methodological quality of observational cohort studies. The NOS assessment will cover three aspects: study population selection, comparability of groups and outcome assessment.

Data synthesis and statistical analysis

The RevMan software (V.5.4.1) will be used for statistical analyses. Given the presence of methodological heterogeneity of different study designs, we will conduct separate meta-analyses using evidence from RCTs and cohort studies.35 36 51 The incidence of intraoperative blood transfusion, postoperative infection, severe complications, POPF, postoperative haemorrhage, DGE and mortality will be expressed as binary variables. For them, the ORs with a 95% CI will be computed using the Mantel-Haenszel method.52 The intraoperative estimated blood loss, operation time and duration of hospitalisation will be expressed as continuous variables.53 For them, the weighted mean difference with a 95% CI will be calculated by the inverse variance method.54 Hozo’s method will be applied to estimate mean and SD when continuous variables are presented using median and IQR.55 A p<0.05 will be deemed statistically significant. The potential interstudy heterogeneity will be assessed using the I2 statistic.56 When the I2 statistic exceeds 50%, a random-effects model will be employed for pooled effect estimates; otherwise, a fixed-effects model will be adopted.

Subgroup and sensitivity analyses

If the data included in this study permit, subgroup analyses of the outcomes will be performed based on age (18–64 and ≥65 years), BMI (25–29.9 kg/m2 and ≥30 kg/m2), the methodological quality of included studies (high quality and low quality). In addition, we will also perform a subgroup analysis stratified by pancreatic ductal adenocarcinoma and other pancreatic neoplasms. To ascertain the robustness of the results, we will perform sensitivity analyses by removing the studies at high risk of bias.

Assessment of publication bias

Publication bias will be assessed through funnel plots when more than 10 studies are included.

Grading the quality of evidence

We will evaluate the quality of evidence of each outcome using the Grading of Recommendations Assessment, Development and Evaluation criteria.57

Ethics and dissemination

This study will collect data from publicly available databases without containing any personally identifiable information, and therefore, ethical approval is not required. The study findings will be published in a peer-reviewed publication.

Patient and public involvement

None.

Discussion

Numerous studies have revealed a strong correlation between high BMI and unfavourable surgical outcomes in patients following pancreaticoduodenectomy.3 58–61 Obesity is commonly regarded as a significant risk factor for bleeding volume, POPF, wound infection, conversion rate and mortality.3 58–61 The higher risk of operative complications may be mainly attributed to excess subcutaneous and visceral adipose tissue, restricted surgical field and operating space and abnormally thickened omentum or mesentery.62–64 Given the challenges in pancreatic surgery facing patients with overweight or obesity, robotic surgery could be considered a promising alternative. Multiple systematic reviews have found that laparoscopic and robotic pancreaticoduodenectomy procedures exhibited no discernible disparities in POPF, DGE, wound infection, length of hospital stay and mortality.12 65 66 Nevertheless, the latter approach has been linked to significantly reduced blood loss and lower conversion rates.12 65 66 Furthermore, the utilisation of robotic pancreaticoduodenectomy has demonstrated notable benefits in the reduction of blood loss, wound infection and length of hospital stay, as well as improved histopathological outcomes when compared with open pancreaticoduodenectomy.5 7 11 34 However, previous research has failed to account for the significant impact of BMI when comparing these outcomes. Consequently, the effectiveness and safety of robotic pancreaticoduodenectomy versus laparoscopic or open pancreaticoduodenectomy in overweight or obese patients remain a subject of controversy. This meta-analytical study aims to investigate the primary short-term clinical outcomes in this regard.

The histological subtypes of pancreas tumours are varied, comprising benign, borderline and malignant lesions.67 68 Pancreatic ductal adenocarcinoma (PDAC) is the most frequent type of pancreatic cancer with high malignancy and extremely poor prognosis.69 Pancreatic head tumour accounts for greater than three-quarters of PDAC, and pancreaticoduodenectomy remains one of the most commonly used surgical procedures for it.70–73 In contrast, lesion enucleation is also assumed to be an effective treatment for small pancreatic tumours with low malignant potential.74–76 Considering the distinction in surgery strategies for different pathologies of pancreatic neoplasms, we will perform a subgroup analysis stratified by PDAC and other pancreatic neoplasms.

The contemporary surgical literature has identified some risk factors for the development of POPF, for example, the diameter of pancreatic duct, the condition of remnant pancreas and BMI.77–80 Clinical studies with high methodological quality can reduce the risk of selective bias by random assignment or propensity score matching, which helps control these potential confounding factors and balance comparability between groups.81–83 Therefore, a subgroup analysis according the methodological quality of included studies will also be conducted.

This meta-analysis represents the inaugural attempt to quantify the occurrence of surgical complications following robotic pancreaticoduodenectomy in a specific population of patients with overweight or obesity. This population is steadily expanding and presents unique challenges for standard laparoscopy and conventional open surgeries. Consequently, the comparison between robotic pancreaticoduodenectomy and its laparoscopic and open counterparts holds particular significance. The outcomes of our study will contribute to elucidating the mechanical benefits associated with robotic pancreaticoduodenectomy, which may ultimately lead to improved surgical outcomes specifically in patients with overweight or obesity.

Ethics statementsPatient consent for publication

Not applicable.