Cancer treatment imposes significant physiological and psychological demands on patients whose reserves are already under strain. Prehabilitation, the systematic optimisation of physical, nutritional, and psychological condition prior to cancer treatment, has emerged as a promising strategy to build reserve and accelerate recovery. Yet critical questions remain around patient selection, optimal dose and delivery, and equitable implementation. In this editorial, we outline the current state of evidence, key challenges, and emerging priorities, and invite contributions to BMC Cancer’s “Prehabilitation in Cancer Care” Special Collection.

BACKGROUND:Gastrointestinal (GI) cancers are a major global health challenge due to their high incidence, mortality, and surgical complication rates. Preoperative physical, nutritional, and psychological vulnerabilities increase the risk of adverse surgical outcomes. Despite this, there is currently no validated, self-report screening tool integrating assessment across all three domains. This scoping review aims to identify and describe existing preoperative screening tools used to assess modifiable physical, nutritional, and psychological domains in adult patients undergoing elective GI cancer surgery. METHODS:We conducted this scoping review in accordance with Arksey and O'Malley's framework and PRISMA-ScR guidelines. Searches were performed across MEDLINE, EMBASE, CINAHL, EBM, and PsycINFO date limited from January 2000 to March 2025. Studies were included if they evaluated preoperative screening tools for physical, nutritional, and/or psychological assessment in adult patients undergoing GI cancer surgery. Data on tool characteristics, domains assessed, administration time, and psychometric properties were extracted and synthesized descriptively. RESULTS:From 2825 initial records, 121 studies were included, encompassing 77 unique screening tools. These were categorized as physical (n = 21), nutritional (n = 16), and psychological (n = 40) tools. Most tools were brief (1-15 items). CONCLUSIONS:Although most screening tools are brief, feasible for self-administration, and freely accessible, none integrated all three domains. Substantial heterogeneity in tools highlights the need for a comprehensive, validated multidomain preoperative screening tool for this population.

INTRODUCTION:Gastrointestinal cancer surgery commonly leads to postoperative complications and other adverse outcomes. While prehabilitation shows promise in reducing adverse postoperative outcomes, most hospitals have resource limitations that preclude its use as standard of care. Additionally, the need to expedite surgery from diagnosis often creates a narrow window for prehabilitation initiatives. Online, self-reported screening tools may address these challenges by facilitating early identification of high-risk patients and enabling targeted preoperative interventions, thereby allowing equitable allocation of limited resources. Therefore, the primary aim of this study is to evaluate the predictive utility of a tri-modal (physical, nutritional, psychological) screening tool for patients undergoing gastrointestinal cancer surgery. METHODS:This prospective international cohort study will recruit 1214 adults undergoing elective gastrointestinal cancer surgery across 35 sites from 19 countries. Participants will complete an online screening tool developed through a comprehensive, multistep, predefined process. The screening tool comprises the Duke Activity Status Index, Patient-Generated Subjective Global Assessment Short Form and the Patient Health Questionnaire-4, in English, Spanish, French or Portuguese. These tools were selected based on a scoping review, followed by an international Delphi consensus process. The primary outcomes include rate of postoperative complications, major complications (Clavien-Dindo Classification grade III-V) and overall complication severity assessed by the Comprehensive Complications Index; all assessed 30 days postoperatively. Secondary outcomes include hospital length of stay, readmission rate within 30 days, discharge destination (home vs other), days at home and alive in 30 days postsurgery, 30-day all-cause mortality and 12-month survival. Primary analyses will establish optimal screening tool cut-points to stratify patients into clinically actionable risk categories for postoperative complications and examine the independent predictive value of these screening scores after adjusting for established clinical risk factors. ETHICS AND DISSEMINATION:This study has received ethical approval from the Sydney Local Health District Human Research and Ethics Committee (X25-0333 and 2025/ETH02465) and has been registered on the Open Science Framework (10.17605/OSF.IO/HVCGD). The results of Preoperative Risk Evaluation for Cancer Treatment will be submitted to reputable journals and presented at national and international conferences.

Objectives This study aims to estimate the rate of recruitment of participants.Design This is a pilot, multicentre, double-blind, placebo-controlled, randomised controlled trial of oral oxycodone and sublingual placebo vs sublingual buprenorphine and oral placebo for postoperative pain management for 7 days after pelvic exenteration.Setting Patients will be recruited from three metropolitan quaternary referral centres that offer advanced gastrointestinal surgery in Australia.Participants The inclusion criteria will be patients over the age of 18 years undergoing pelvic exenteration surgery and exclusion criteria are previous adverse events related to the study drugs, currently requiring monoamine oxidase inhibitor medications and if epidural analgesia is planned in the perioperative period.Interventions Enrolled patients will undergo pelvic exenteration surgery and be initiated postoperatively on patient-controlled analgesia. In the postoperative period, when clinically appropriate to take oral medications, patients will be commenced on trial analgesia for 7 days. Participants will be randomised to receive either oral active oxycodone 5–10 mg up to 3 hourly as required (with sublingual placebo) or sublingual active buprenorphine 200–400 mcg 3 hourly as required (with oral placebo).Main outcome measures The primary outcome measure is the rate of recruitment over a 6-month period. Secondary outcomes include an assessment of missing data, protocol adherence and acceptability of the trial to participants.Ethics and dissemination The trial received ethics approval from Sydney Local Health District, Royal Prince Alfred Hospital Human Research Ethics Committee (No: X25-0128 & 2025/ETH01058). The results of the study will be disseminated by publication and presentation at local annual scientific meetings in Australia.Trial registration number The study protocol is prospectively registered at the Australian New Zealand Clinical Trials Registry (ANZCTR) (www.anzctr.org.au; ACTRN12625000901404).

INTRODUCTION:Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) is a complex and costly treatment for peritoneal surface malignancies. While preoperative frailty is known to worsen postoperative outcomes, its economic impact in CRS + HIPEC remains underexplored. This study evaluated the association between preoperative frailty and in-hospital costs in this population. MATERIALS AND METHODS:A retrospective cohort study was conducted at a tertiary center in Sydney, Australia, including adults who underwent CRS + HIPEC from May 2017 to June 2024. Frailty was assessed using the Clinical Frailty Scale (CFS), with scores of 4 or higher classified as frail. Patient characteristics, surgical outcomes, and in-hospital cost data, including staff, intensive care, diagnostics, theatre, ward, and other services, were collected. Mann-Whitney U tests and chi-square tests were used for comparisons. Multivariable linear regression identified cost drivers in frail patients. RESULTS:Among 466 patients, 60 (12.9%) were classified as frail. Frail patients were significantly older than non-frail patients. Cost differences were particularly evident in staffing, diagnostics, and ward-related care, with frail patients incurring higher expenses across all categories. Total in-hospital costs were significantly higher in frail compared to non-frail patients (median AU$115,282 vs AU$106,938; p = 0.005). Multivariate analysis identified intensive care unit stay as the primary driver of total in-hospital cost within the frail cohort. DISCUSSION:Preoperative frailty is independently associated with increased in-hospital costs among patients undergoing CRS + HIPEC. These findings highlight the value of incorporating frailty assessment into preoperative evaluation and suggest a need for targeted perioperative strategies to optimise outcomes and resource use in frail surgical populations.

INTRODUCTION:To explicitly assess the impact of theory in implementation strategies, it is essential to isolate theoretical components while controlling other variables. AIM:This exploratory two-arm cluster-randomized implementation trial compared theory-driven versus intuition-based approaches to the development of strategies to improve risk-appropriate tumor testing and referral to genetics services for Lynch syndrome (LS), a hereditary cancer predisposition condition. METHODS:Seven major Australian hospitals received an identical, seven-step implementation approach, with the only difference being either the use of theory-driven or intuition-based implementation strategy development, which was randomly assigned (theory n = 4; intuition n = 3). The theory-driven approach was guided by the Theoretical Domains Framework (step 4) and matched Behavior Change Techniques (step 5), with all other steps identical between both trial arms. The primary outcome was the rate of risk-appropriate LS tumor testing and referral within 2 months of colorectal cancer (CRC) resection, using data from January 1, 2017 to September 30, 2021 (n = 3,321 patients). Secondary outcomes included the proportion of risk-appropriate patients with a genetic referral. RESULTS:The theory-driven arm showed a modest but non-significant improvement in the primary outcome of risk-appropriate LS pathway completion (adjusted risk ratio [aRR]=1.22, 95% CI: 0.92- 1.61, p  = 0.1713); however, this was driven by one large hospital, with null effect when excluding that hospital (aRR = 1.00, 95% CI: 0.86-1.18, p  = 0.9639) and heterogeneous results across different hospitals. For patients with high LS risk tumor test results, the theory-driven arm showed a significantly lower proportion without a genetics referral (secondary outcome: aRR = 0.50, 95% CI: 0.41-0.61, p  < 0.0001). CONCLUSION:Theory-driven implementation led to stronger improvements in a secondary outcome. Primary outcome evidence was inconclusive. While theory-driven approaches led to some improvements in a secondary outcome, there was no conclusive difference in the primary outcome. A published process evaluation reports on the contextual factors influencing results at each site, as well as theoretical alignment of intuitive strategies and their proposed mechanisms of action. This trial design offers a template for isolating and evaluating the contribution of theory to implementation strategies. TRIAL REGISTRATION:Australian New Zealand Clinical Trials Registry, ACTRN12618001072202. Registered June 27, 2018 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375348&isReview=true. SPANISH ABSTRACT:http://links.lww.com/IJEBH/A491.

BACKGROUND:Pelvic exenteration (PE) is a radical surgery for advanced pelvic malignancies that carries substantial psychosocial impacts. Assessing distress is critical for timely support. AIMS:To evaluate the responsiveness-to-change and convergent validity of the distress thermometer (DT), and to determine an optimal cutoff score for detecting clinically significant distress in a PE cohort. METHODS:Secondary analyses of cohort study data involving adult patients who underwent PE at a quaternary referral hospital. Responsiveness was evaluated by determining whether the DT differentiated cases of decreased emotional well-being and health-related quality of life from pre- to post-surgery, using the Functional Assessment of Cancer Therapy-General (FACT-G), FACT-Colorectal, and Emotional Well-Being (EWB) subscale as external criteria. Convergent validity was evaluated using the correlation between the DT and the EWB subscale scores. Cutoff scores were examined by reviewing the following indices, using an existing EWB cutoff as an external anchor: sensitivity, specificity, positive/negative predictive values, and clinical utility index (CUI). RESULTS:The analysis included 377 patients (mean age: 61 years, 56% male; 41% recurrent rectal cancer). The DT demonstrated responsiveness, with AUCs > 0.7 for detecting emotional and quality-of-life decline post-surgery. Convergent validity was demonstrated through a moderate correlation between the DT and the EWB subscale scores (rs = -0.56, p < 0.001). The optimal DT cutoff score was 4: Sensitivity; 87.0%, Specificity; 52.7%, CUI- value; 0.49 (ruling out cases: satisfactory utility), CUI+ value; 0.33 (case finding: poor utility). CONCLUSION:The DT is a valid and responsive tool for detecting psychological distress in PE patients. Its high sensitivity supports its use in routine screening.

Objective: To establish globally applicable benchmark outcomes for pelvic exenteration (PE) in patients with locally advanced primary rectal cancer (LARC) and locally recurrent rectal cancer (LRRC), using outcomes achieved at highly specialised centres. Background: PE is established as the standard of care for selected patients with LARC and LRRC. There are currently no available benchmarks against which surgical performance in PE can be compared for audit and quality improvement. Methods: This international multicentre retrospective cohort study included patients undergoing PE for LARC or LRRC at 16 highly experienced centres between 2018 and 2023. Ten outcome benchmarks were established in a lower-risk subgroup. Benchmarks were defined by the 75th percentile of the results achieved at the individual centres. Results: Seven hundred sixty-three patients underwent PE, of which 464 patients (61%) had LARCs and 299 (39%) had LRRCs. Five hundred forty-four patients (71%) who met predefined lower-risk criteria formed the benchmark cohort. For patients with LARC, the calculated benchmark threshold for major complication rate was <= 44%; Comprehensive Complication Index: <= 30.2; 30-day mortality rate: 0%; 90-day mortality rate: <= 4.3%; R0 resection rate: >= 79%. For patients with LRRC, the calculated benchmark threshold for major complication rate was <= 53%; Comprehensive Complication Index: <= 34.1; 30-day mortality rate: 0%; 90-day mortality rate: <= 6%; R0 resection rate: >= 77%. Conclusions: The reported benchmarks for PE in patients with LARC and LRRC represent the best available care for this patient group globally and can be used for rigorous assessment of surgical quality and to facilitate quality improvement initiatives at international exenteration centres.

OBJECTIVE:To assess sample size calculation reporting in randomized controlled trials (RCTs) investigating prehabilitation interventions in oncological surgery patients. DATA SOURCES:A systematic literature search was performed in multiple medical databases from inception to April 2023, including MEDLINE, Embase, The Cochrane Library, CINHAL, AMED, and PsychINFO. STUDY SELECTION:The inclusion criteria used were RCTs evaluating effectiveness of exercise, nutrition, and/or psychological interventions on postoperative outcomes of adult patients undergoing oncological surgery. DATA EXTRACTION:Two authors (DS and SV) extracted information on the sample size calculation parameters, including type I error (α), power (1-β), mean (or mean difference between randomization arms), and variance (eg, standard deviation) for continuous outcomes, and event rates or event rate difference between randomization arms for dichotomous outcomes. When possible, we recalculated the sample size required using the collected data, given a 10% margin of error. DATA SYNTHESIS:Of the 59 included publications (58 RCTs), 26 (44%) reported sufficient information to complete sample size recalculation. Of those that provided sufficient information allowing us to recalculate the required sample size, 11 (42%) were within a 10% margin of the reported sample size, whereas 9 (35%) were >10% higher than reported sample size and 6 (23%) were >10% lower than reported sample size. CONCLUSIONS:Over half of the published RCTs in this field exhibit poor sample size calculation reporting. Most RCTs that report sufficient sample size information were underpowered. More stringent reporting requirements are necessary.

The number of randomized controlled trials (RCTs) exploring the effectiveness of prehabilitation on improving postoperative outcomes for cancer surgery is increasing. Fragility index (FI) and reverse fragility index (RFI) represent the minimum number of participants whose status needs to change from an “event” to a “non-event,” thereby the results change from statistically significant to nonsignificant (or vice versa for RFI). Fragility quotient (FQ) allows for the FI or RFI to be standardized to the sample size of the study. This review aims to examine the robustness of prehabilitation RCTs by assessing their FI, RFI, and FQ. The Allied and Complementary Medicine Database (AMED), Cumulative Index of Nursing and Allied Health Literature (CINAHL), Cochrane Central Register of Controlled Trials (CENTRAL), Embase, Medline, and PsycINFO were searched from inception to December 2023. Eligible articles included RCTs, with parallel arm design, evaluating the effectiveness of prehabilitation intervention on the reduction of postoperative complications in selected major oncologic surgeries. FI and RFI were determined using the R fragility package. After screening 2486 publications, 76 RCTs met inclusion criteria. Most of the included RCTs explored the effectiveness of nutritional prehabilitation (N = 38; 50

BACKGROUND:Despite recent improvements in survival after pelvic exenteration for locally recurrent rectal cancer, long-term re-recurrence remains a significant cause of mortality. The aim of this study was to report the patterns and outcomes of recurrence after exenteration and to determine how surgical resection margins and the site of disease recurrence influence survival. METHODS:Consecutive patients who underwent pelvic exenteration for locally recurrent rectal cancer at a high-volume exenteration centre between 1994 and 2023 were included. Clinicopathological and survival data were extracted from a prospective database. Recurrence data were retrospectively collected from patient medical records. RESULTS:In total, 282 patients were included in the analysis, with a median follow-up of 3.5 years. The R0 resection rate was 81.6% (230 patients). Of the 255 patients with available data, 130 (51.0%) developed recurrence (30 (11.8%), 79 (31.0%), and 21 (8.2%) with only local recurrence, only distant recurrence, and both local and distant recurrence respectively). R0 resection was associated with a lower local recurrence rate versus R1/2 resection (13.9% versus 36.5%; P = 0.001), but a similar distant recurrence rate (36.5% versus 30.8%). The lungs were the most common site of recurrence after R0 resection. The 5-year survival rate was 42.3% for the overall study cohort and 48.0% after R0 resection (versus 17.2% after R1/2 resection; P < 0.001). Local recurrence after exenteration was independently associated with poorer survival (HR 3.84 (95% c.i. 2.24 to 6.57); P < 0.001). CONCLUSION:R0 resection margins may be associated with improved survival due to better local control, rather than distant control. The lungs are the most common site of recurrence after curative resection.

BACKGROUND:The evidence of prehabilitation in frail patients with cancer is lacking. This systematic review and meta-analysis aimed to determine the effectiveness of prehabilitation on postoperative complications, and hospital length of stay (LOS) in this population. METHODS:A comprehensive search was performed in MEDLINE, Embase, Cochrane, CINAHL, AMED, and PsycINFO, encompassing all records from inception to December 2023. The outcomes of interest included postoperative complications and LOS. Risk of bias was assessed using the revised Cochrane risk of bias tool (RoB2) and GRADE was used to determine the quality of evidence. Relative risk (RR) or mean difference (MD) along with its 95% confidence interval (CI) were calculated by using random-effects meta-analysis. RESULTS:Five randomised controlled trials (four trials in colorectal or colon cancer), including 466 patients (230 patients undergoing prehabilitation and 236 standard of care controls), were included. Prehabilitation reduced any postoperative complications (RR = 0.82; 95% CI = 0.71-0.95; four trials, N = 465), but no effect was observed for major postoperative complications (RR = 0.89: 95% CI = 0.71-1.11; two trials, N = 226) and LOS (MD = 0.3, 95% CI = -0.68 to 1.28; three trials, N = 349). A single trial (including 57 patients) investigated the effect of exercise-only on a range of postoperative complications, with no significant difference between groups observed. CONCLUSIONS:In our systematic review and meta-analysis, we found that prehabilitation significantly decreased the rate of any postoperative complications in frail patients with cancer undergoing surgery. The role of prehabilitation in improving major postoperative outcomes is unclear owing to the limited amount of evidence.

Background Frailty is increasingly recognised as a predictor of poor surgical outcomes. However, its impact in determining outcomes following cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) remains underreported. Thus, this study aims to determine the association between preoperative frailty and surgical outcomes including survival in patients undergoing CRS + HIPEC. Methods This retrospective cohort study included patients who underwent CRS + HIPEC at the Royal Prince Alfred Hospital between May 2017 and June 2024. Frailty was assessed preoperatively using the Clinical Frailty Scale (CFS), with patients classified as frail (CFS ≥4) or not frail (CFS <4). Other outcomes included surgery duration, intensive care unit (ICU) and hospital stays, postoperative complications, recurrence rates, and survival. Subgroup analyses were performed based on age group (<65 years versus ≥65 years). Results Of the 466 patients included, 60 (12.9 %) were classified as frail. Frailty was associated with longer surgery durations (median: 10.0 vs. 9.8 h; p = 0.015), longer ICU stay (median: 5.5 vs. 5.0 days; p = 0.037), hospital stay (median: 21.0 vs. 17.0 days; p < 0.001), and worst survival outcomes (p = 0.002). Age-stratified analysis revealed that frailty was associated with prolonged hospital stay across both subgroups. Among patients aged ≥65 years, frailty was also significantly associated with longer surgery durations (p < 0.001) and length of ICU stay (p = 0.013). Conclusions Preoperative frailty was associated with worse postoperative outcomes in patients undergoing CRS + HIPEC. These findings highlight the importance of routine frailty assessments to guide surgical planning and improve patient care. Future research should explore interventions such as prehabilitation to mitigate the adverse effects of frailty and optimise outcomes in this vulnerable population.

BACKGROUND:For patients with locally recurrent rectal cancer (LRRC), the potential benefit of exenteration (long-term disease control or cure) must be weighed against the morbidity and functional consequences of surgery. Consensus-derived priority outcomes of exenteration were recently established through a comprehensive series of studies, and represent shared priorities of patients, carers, and clinicians. This study aimed to identify preoperative predictors of priority outcomes following pelvic exenteration for LRRC, specifically R0 resection, overall survival, and quality of life (QOL). METHODS:Prospectively collected data for 300 patients who underwent pelvic exenteration for LRRC between 1994 and 2023 were extracted from an institutional database. Preoperative prediction models for R0 resection, overall survival, and global QOL at 12 months (priority outcomes) were developed using logistic regression (R0 resection), Cox regression (survival), and linear regression (QOL). RESULTS:R0 resection was achieved in 81 % of patients (244/300). Neoadjuvant radiotherapy (OR = 2.773, 95 % CI = 1.384-5.555, p = 0.004) and the need for pelvic bone excision (OR = 2.311, 95 % CI = 1.20-4.45, p = 0.012) were associated with improved R0 resection rates. The need for sciatic nerve resection was associated with lower R0 resection rates (OR = 0.365, 95 % CI = 0.177-0.753, p = 0.006). Age was independently associated with overall survival (HR = 1.022, 95 % CI = 1.006-1.039, p = 0.007). Baseline QOL score was independently associated with a decline in QOL between baseline and 12 months (β = -1.011, 95 % CI = -1.196 to -0.825, p < 0.001). CONCLUSIONS:These findings enable evidence-based prediction of R0 resection, survival and QOL following exenteration for LRRC. This will support development of clinical prediction tools to improve patient selection, enhance preoperative counseling, and inform shared decision-making.

BACKGROUND: Cytoreductive surgery and Hyperthermic Intraperitoneal Chemotherapy is a widely accepted treatment option for patients presenting with colorectal peritoneal metastases however, evidence on quality-of-life outcomes is lacking. OBJECTIVE: To assess quality of life trajectories and surgical outcomes following Cytoreductive surgery and Hyperthermic Intraperitoneal Chemotherapy in two peritoneal malignancy units in Australia and the United Kingdom. DESIGN: Prospective cohort study. SETTINGS: The Royal Prince Alfred Hospital (Australia) and Basingstoke & North Hampshire Hospital (United Kingdom). PATIENTS: Undergoing Cytoreductive surgery and Hyperthermic Intraperitoneal Chemotherapy for colorectal peritoneal metastases from June-2019 to March-2023. MAIN OUTCOME MEASURES: Primary outcome was quality of life, assessed using the Short-Form 36 Survey and the Functional Assessment of Cancer Therapy - Colorectal at baseline, pre-discharge, and 3-, 6-, and 12-months post-surgery. Secondary outcomes included surgical parameters and the impact of peritoneal cancer index on primary outcomes. RESULTS: A total of 193 patients (99 from Australia, 94 from United Kingdom) were included. Australian patients were younger (median 54.0 vs 61.0 years; p = 0.005) and had higher peritoneal cancer index scores (median 10.0 vs 5.0; p < 0.001), consequently having longer operation , intensive care unit stays, and hospital stays, with more postoperative complications (all p < 0.001). Quality of life returned to baseline levels within 3-6 months post-surgery and was practically identical in both countries. Overall survival was better in the United Kingdom cohort ( p = 0.035), but recurrence rates were similar. Higher peritoneal cancer index scores were associated with worse surgical and survival outcomes, but patients with peritoneal cancer index >15 still demonstrated a 36-month survival rate of 45.7%. LIMITATIONS: Potential recall bias and missing data at longer follow-up. CONCLUSION: Cytoreductive surgery and Hyperthermic Intraperitoneal Chemotherapy leads to temporary quality of life decline with recovery to baseline within 3-6 months for most patients with colorectal peritoneal metastases. While quality of life trajectories were similar between countries, patients with peritoneal cancer index >15 demonstrated poorer quality of life at 6-12 months, particularly with disease recurrence. Future research should focus on strategies to maintain long-term quality of life improvements, especially in high-risk patients. See Video Abstract .

AIM:Cytoreductive surgery provides a chance for long-term survival and cure in selected patients with colorectal peritoneal metastases. As clinical and academic interest in this field increases, heterogeneity in outcome reporting hinders the valid and meaningful synthesis of data into high-quality meta-analyses. The aim of this systemic review was to investigate variability in outcome reporting following cytoreductive surgery with or without intraperitoneal chemotherapy for colorectal peritoneal metastases. METHOD:Five electronic databases [MEDLINE, Embase, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL) and Cumulative Index to Nursing and Allied Health Literature (CINAHL)] were interrogated from 2000 to October 2023 to identify all reported outcomes in the current literature. Extracted outcomes were catalogued and reviewed by a multidisciplinary working group into standardized terms and domains. RESULTS:A total of 294 studies, from 5112 screened, were included for analysis. We extracted 2903 outcomes verbatim from included studies and catalogued them into 85 standardized outcomes across seven outcome domains. The most frequently reported domains were survival, in 274 (93%) studies, and pathological outcomes, in 232 (79%) studies. Outcomes pertaining to function and life impact were only reported in seven (2%) studies. Reported outcomes were only defined in 35% of cases, and significant variability existed between definitions. CONCLUSION:This systematic review highlights the heterogeneity of outcome measurement and reporting following cytoreductive surgery for colorectal peritoneal metastases. Patient-reported outcomes are relatively underrepresented in the current literature. The results of this review will inform an international collaborative effort to create a core outcome set to address these issues.