The obesity paradox in beyond total mesorectal excision surgery for locally advanced and recurrent rectal cancer

Impact of obesity on postoperative complications in colorectal cancer surgery: A systematic review and meta-analysis

BACKGROUND

Obesity has been increasingly recognized as a factor that influences postoperative outcomes in colorectal cancer surgery. However, its impact on surgical complications, mortality, and oncological outcomes remains controversial. This systematic review and meta-analysis aimed to evaluate the association between obesity and postoperative complications in colorectal cancer surgery.

METHODS

A comprehensive search was conducted in MEDLINE/PubMed, Scopus, and Embase, including studies evaluating body mass index (BMI) in relation to postoperative complications such as infections, anastomotic leakage, postoperative ileus, bleeding, reoperation, and mortality. Data synthesis involved a qualitative analysis of all eligible studies and a meta-analysis when applicable. The quality of the studies included was assessed using the Newcastle-Ottawa Scale, while the certainty of evidence was evaluated through the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach.

RESULTS

Twenty-nine studies were included in the qualitative analysis and 17 were eligible for the meta-analysis. Compared to BMI <30 kg/m², patients with BMI ≥30 kg/m² showed significantly higher risk of any type of surgical site infection (OR=1.49; 95% CI: 1.37-1.70; low certainty). No significant differences were found in mortality (OR=1.23; 95% CI: 0.72-2.11; very low certainty), hemorrhage (OR=1.05; 95% CI: 0.97-1.14; very low certainty), or gastrointestinal complications (OR=1.10; 95% CI: 0.96-1.26; very low certainty).

CONCLUSION

Obesity significantly increases the risk of surgical site infections in colorectal cancer surgery. Although its impact on mortality and gastrointestinal complications remains unclear, implementing preoperative optimization protocols specifically aimed at obesity management could mitigate these surgical risks. The certainty of evidence ranges from low to very low, highlighting the need for high-quality prospective studies with standardized BMI criteria and surgical protocols.

Patients with class III obesity are at elevated risk of postoperative morbidity after surgery for left-sided diverticular disease: a retrospective population-level study

BACKGROUND

Although obesity is a well-established risk factor for the development of diverticular disease, studies focusing on the effect of body mass index (BMI) on postoperative outcomes require updating. This population-level retrospective cohort study was designed to evaluate the effect of BMI on postoperative outcomes after operative intervention for left-sided diverticular disease.

METHODS

This was a population-based retrospective cohort study using the Healthcare Cost and Utilization Project National Inpatient Sample (NIS) (September 1, 2015 to December 31, 2019). The International Classification of Diseases, 10th Revision, Clinical Modification codes were used to identify a cohort of adult patients with a primary admission diagnosis of diverticulitis. Patients were stratified according to obesity status (ie, not obese: BMI of <30.0 kg/m2; class I obesity: BMI of 30.0-34.9 kg/m2; class II obesity: BMI of 35.0-39.9 kg/m2; class III obesity: BMI of >40.0 kg/m2). The primary outcome was overall in-hospital postoperative morbidity. The multivariate regression models were fit.

RESULTS

There were 33,029 patients identified in the NIS who underwent left-sided colonic resection for diverticular disease. There were 27,212 patients who were not obese, 2209 patients with class I obesity, 1710 patients with class II obesity, and 1898 patients with class III obesity. Patients with class III obesity (ie, a BMI of >40.0 kg/m2) had 72.7% higher odds (95% CI, 1.54-1.94) of experiencing in-hospital postoperative morbidity than patients with a BMI of <30.0 kg/m2. Patients with class III obesity had 26.9% higher odds (95% CI, 0.98-1.65) of experiencing in-hospital postoperative infection, 54.6% higher odds (95% CI, 1.35-1.77) of experiencing in-hospital postoperative gastrointestinal complications, and 70.9% higher odds (95% CI, 1.48-1.97) of experiencing in-hospital postoperative genitourinary complications than those with a BMI of <30.0 kg/m2.

CONCLUSION

Patients with class III obesity undergoing operative intervention for colonic diverticular disease are at increased risk of short-term postoperative morbidity compared with those with a BMI of <30.0 kg/m2.

Prediction model construction for the occurrence of LARS after neoadjuvant therapy combined with laparoscopic total mesorectal excision in male patients with mid-low rectal cancer

BACKGROUND

Neoadjuvant chemoradiotherapy for rectal cancer improves surgical outcomes and reduces recurrence but can cause low anterior resection syndrome (LARS), affecting quality of life. This study aims to predict the risk of LARS in male patients with mid-low rectal cancer after laparoscopic total mesorectal excision (TME).

METHODS

Clinical data from 203 male patients with mid-low rectal cancer who underwent neoadjuvant therapy and laparoscopic resection were collected. Patients were divided into training (n=143) and validation (n=60) cohorts. LARS risk factors were identified using logistic regression, and a predictive model was constructed and validated using ROC curve, Hosmer-Lemeshow test, calibration curve, and decision curve analysis (DCA).

RESULTS

LARS occurred in 53.6% of the patients in this study. Multivariate logistic regression analysis revealed that BMI ≥ 25 kg/m², tumor distance from the anal margin < 5 cm, radiotherapy, and anastomotic leakage were independent risk factors for postoperative LARS in patients (P < 0.05). The areas under the ROC curves for the training cohort and validation cohort were 0.866 (95% CI: 0.807-0.925) and 0.724 (95% CI: 0.595-0.853), respectively, with both groups showing good goodness-of-fit test results (P > 0.05). The DCA curve indicated that the model had a high clinical utility.

CONCLUSIONS

BMI ≥ 25 kg/m², tumor distance from the anal margin < 5 cm, radiotherapy, and anastomotic leakage are independent risk factors for the occurrence of LARS after neoadjuvant therapy combined with laparoscopic TME in male patients with mid-low rectal cancer. These factors should be emphasized in clinical practice, and corresponding preventive measures should be promptly implemented.

Post-diagnosis adiposity and colorectal cancer prognosis: A Global Cancer Update Programme (CUP Global) systematic literature review and meta-analysis

The adiposity influence on colorectal cancer prognosis remains poorly characterised. We performed a systematic review and meta-analysis on post-diagnosis adiposity measures (body mass index [BMI], waist circumference, waist-to-hip ratio, weight) or their changes and colorectal cancer outcomes. PubMed and Embase were searched through 28 February 2022. Random-effects meta-analyses were conducted when at least three studies had sufficient information. The quality of evidence was interpreted and graded by the Global Cancer Update Programme (CUP Global) independent Expert Committee on Cancer Survivorship and Expert Panel. We reviewed 124 observational studies (85 publications). Meta-analyses were possible for BMI and all-cause mortality, colorectal cancer-specific mortality, and cancer recurrence/disease-free survival. Non-linear meta-analysis indicated a reverse J-shaped association between BMI and colorectal cancer outcomes (nadir at BMI 28 kg/m2). The highest risk, relative to the nadir, was observed at both ends of the BMI distribution (18 and 38 kg/m2), namely 60% and 23% higher risk for all-cause mortality; 95% and 26% for colorectal cancer-specific mortality; and 37% and 24% for cancer recurrence/disease-free survival, respectively. The higher risk with low BMI was attenuated in secondary analyses of RCTs (compared to cohort studies), among studies with longer follow-up, and in women suggesting potential methodological limitations and/or altered physiological state. Descriptively synthesised studies on other adiposity-outcome associations of interest were limited in number and methodological quality. All the associations were graded as limited (likelihood of causality: no conclusion) due to potential methodological limitations (reverse causation, confounding, selection bias). Additional well-designed observational studies and interventional trials are needed to provide further clarification.

Body mass index-based predictions and personalized clinical strategies for colorectal cancer in the context of PPPM

Currently colorectal cancer (CRC) is the third most prevalent cancer worldwide. Body mass index (BMI) is frequently used in CRC screening and risk assessment to quantitatively evaluate weight. However, the impact of BMI on clinical strategies for CRC has received little attention. Within the framework of the predictive, preventive, and personalized medicine (3PM/PPPM), we hypothesized that BMI stratification would affect the primary, secondary, and tertiary care options for CRC and we conducted a critical evidence-based review. BMI dynamically influences CRC outcomes, which helps avoiding adverse treatment effects. The outcome of surgical and radiation treatment is adversely affected by overweight (BMI ≥ 30) or underweight (BMI < 20). A number of interventions, such as enhanced recovery after surgery and robotic surgery, can be applied to CRC at all levels of BMI. BMI-controlling modalities such as exercise, diet control, nutritional therapy, and medications may be potentially beneficial for patients with CRC. Patients with overweight are advised to lose weight through diet, medication, and physical activity while patients suffering of underweight require more focus on nutrition. BMI assists patients with CRC in better managing their weight, which decreases the incidence of adverse prognostic events during treatment. BMI is accessible, noninvasive, and highly predictive of clinical outcomes in CRC. The cost-benefit of the PPPM paradigm in developing countries can be advanced, and the clinical benefit for patients can be improved with the promotion of BMI-based clinical strategy models for CRC.

The obesity paradox in patients with colorectal cancer: a systematic review and meta-analysis

CONTEXT

Obesity is widely regarded as an established risk factor for colorectal cancer (CRC). However, recent studies have shown that lower mortality and better cancer-specific survival were observed in CRC patients with elevated body mass index (BMI), an example of the obesity paradox, which is the inverse correlation between obesity and mortality in some populations.

OBJECTIVE

The aim of this systematic review and meta-analysis was to investigate the association between BMI and CRC outcomes.

DATA SOURCES

PubMed, Web of Science, MEDLINE, the Cochrane Library, and Embase databases were searched for relevant articles published from inception to December 31, 2020.

STUDY SELECTION

Studies comparing the prognosis of CRC patients with obesity or overweight with that of normal-weight CRC patients were eligible.

DATA EXTRACTION

Data were extracted by 2 reviewers independently; differences were resolved by a third reviewer. BMI was classified according to WHO categories.

DATA ANALYSIS

To assess the prognostic effects of different BMI categories in CRC patients, hazard ratios and 95%CIs of overall survival, disease-free survival, and cancer-specific survival were extracted from included articles.

RESULTS

Sixteen studies (55 391 patients in total) were included. Higher BMI was significantly associated with more favorable CRC outcomes. Compared with normal-weight patients, underweight patients had worse overall survival (HR = 1.26; 95%CI, 1.15-1.37) and disease-free survival (HR = 1.19; 95%CI, 1.11-1.27, while patients with overweight had better overall survival (HR = 0.92; 95%CI, 0.86-0.99), disease-free survival (HR = 0.96; 95%CI, 0.93-1.00), and cancer-specific survival (HR = 0.86; 95%CI, 0.76-0.98). Patients with morbid obesity had worse overall survival (HR = 1.12; 95%CI, 1.02-1.22) and disease-free survival (HR = 1.15; 95%CI, 1.07-1.24) than normal-weight patients. There was no significant difference in cancer-specific survival between patients with obesity (HR = 0.94; 95%CI, 0.76-1.16) and patients with normal weight, nor between patients with underweight and patients with normal weight (HR = 1.14; 95%CI, 0.82-1.58).

CONCLUSIONS

CRC patients with a higher BMI appear to have reduced mortality compared with normal-weight CRC patients, even though higher BMI/obesity is an established determinant for the development of CRC.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020202320.

The impact of body mass index on prognosis in patients with colon carcinoma

BACKGROUND

The impact of body mass index (BMI) on prognosis in patients with curatively resected stage I-III colon carcinoma was analyzed.

METHODS

The prospectively collected data of 694 patients who underwent complete mesocolic excision between 2003 and 2014 were analyzed. BMI was classified into four categories: underweight (BMI < 18.5 kg/m²; n = 13), normal weight (BMI 18.5 to 24.9 kg/m²; n = 221), overweight (BMI 25.0 to 29.9 kg/m²; n = 309), and obese (BMI ≥ 30.0 kg/m²; n = 151). Univariate and multivariate analyses for comparison of prognosis were performed.

RESULTS

The 5-year rate of locoregional recurrence in all 694 patients was 2.1%, and no differences were found with respect to BMI (p = 0.759). For distant metastasis, the 5-year rate for all patients was 13.4%, and BMI did not have a significant impact (p = 0.593). The 5-year rate of disease-free survival for all 694 patients was 72.4%. The differences with respect to BMI were not found to be significant in univariate analysis (p = 0.222). In multivariate Cox regression analysis, disease-free survival was significantly better in obese patients (HR 0.7; p = 0.034). Regarding overall survival, the 5-year rate for all patients was 78.1%. In univariate analyses, no significant differences were found for BMI (p = 0.094). In the Cox regression analysis, overweight and obese patients had significantly better survival (overweight: HR 0.7; p = 0.027; obese: HR 0.6; p = 0.019).

CONCLUSION

The better survival of overweight and obese patients in multivariate analyses must be interpreted with caution. It is influenced by several factors and seems to correspond to the phenomenon of the obesity paradox.

Impact of body-mass index on treatment and outcome in locally advanced rectal cancer: A secondary, post-hoc analysis of the CAO/ARO/AIO-04 randomized phase III trial

BACKGROUND

A better understanding of the impact of body-mass index (BMI) on the course of multimodal therapy and oncologic outcome in locally advanced rectal cancer could provide new insights for optimization of treatment and supportive strategies.

PATIENTS AND METHODS

Correlations of BMI with pretreatment clinical, surgical, and pathological characteristics, toxicity and treatment adherence using the Pearson's Chi-squared test or logistic regression were analyzed in the CAO/ARO/AIO-04 III trial cohort (n = 1236). One-way ANOVA or Welch test were used to analyze correlations of baseline blood-parameters and BMI. The prognostic role of BMI was examined with log-rank test and multivariate cox regression.

RESULTS

Obese had a better ECOG performance status (P = 0.027) but were less likely to undergo sphincter preserving surgery (P = 0.01). Post-surgical complications did not differ significantly between BMI classes, whereas underweight was associated with increased neutrophil (P = 0.025) and platelet counts (P < 0.001), poorer TME quality (P = 0.007) and increased incidence of acute organ toxicity (P < 0.001). After a median follow-up of 50 months, underweight [HR 1.896, P = 0.014] and overweight [HR 1.392, P = 0.042] were associated with worse DFS. Obese patients had an increased risk of death [HR 1.653, P = 0.032]. Normalweight men showed superior OS compared to underweight [HR 4.070, P = 0.002], overweight [HR 2.077, P = 0.010], severe overweight [HR 1.886, P = 0.026] and obese [HR 2.046, P = 0.015] men. Adding oxaliplatin to standard CRT significantly improved DFS in obese patients (P = 0.034).

CONCLUSION

In our study, underweight and overweight correlated with inferior DFS, underweight experienced more organ toxicity and obesity was associated with an increased risk of abdominoperineal resection and poorer overall survival.

The impact of obesity and morbid obesity on urgent/emergency colorectal resections: a regional database analysis

BACKGROUND

The obesity rate is projected to reach 50% by 2030. Obesity may be modifiable prior to elective colorectal surgery, but there is no opportunity for weight loss when patients present for urgent/emergency operations. The impact of obesity focused on urgent/emergent colorectal operations has not been fully characterized. The study aim was to determine outcomes of obese patients who undergo urgent/emergency colorectal surgery and differences when compared with elective outcomes.

METHODS

This is a retrospective cohort study of 30-day outcomes for normal (BMI 18.5-25), obese (BMI 30-39.9), and morbidly obese (BMI > 40) patients in the Michigan Surgical Quality Collaborative between 1/1/2009 and 12/31/2018. Propensity score weighting was used to derive adjusted rates for overall morbidity, mortality, and specific complications. Primary outcome was postoperative complications (any morbidity).

RESULTS

The study included 5268 urgent/emergency and 10,414 elective colorectal surgery patients. Postoperative complications were significantly more common in morbidly obese and obese than the normal BMI group for both urgent/emergency (morbidly obese 42.76% vs 33.75%, p = 0.003; obese 36.46% vs 33.75%, p = 0.043) and elective (morbidly obese 18.17% vs 13.36%, p = 0.004; obese 15.45% vs 13.36%, p = 0.011) operations. Surgical site infections are were significantly more common in morbidly obese and obese BMI groups as compared to normal BMI for both urgent/emergency and elective cases. Mortality was significantly higher in the morbidly obese (14.93% vs 11.44%, p = 0.013) but not obese BMI groups as compared to the normal BMI group for urgent/emergency cases. Mortality for all groups undergoing elective operations was < 1% and with no significant differences.

CONCLUSIONS

Morbid obesity and obesity are associated with complications that are largely driven by surgical site infections after both urgent/emergency and elective colorectal surgery. Obesity is a risk factor difficult to modify prior to urgent/emergency surgery. Managing complications related to obesity after colorectal surgery will be a continued challenge with projected increasing obesity rates.

Obesity Paradox: Laboratory Findings in Uncomplicated Obesity. Is Bias a Plausible Explanation?

OBJECTIVES

Obesity predisposes to multiple diseases, such as heart disease, diabetes, stroke, arthritis, and malignancy. However, obese patients have better outcomes than normal-weight patients with some of these disorders, including those admitted to critical care units. We compared the results for common laboratory tests in patients with uncomplicated obesity against the findings in normal-weight patients.

METHODS

Patients who had a comprehensive metabolic profile test were identified. Patients with acute and/or chronic debilitating disorders were excluded, and the laboratory parameters were compared among 4 groups based on body mass index.

RESULTS

With the exception of elevated triglycerides and lower high-density lipoprotein in obese and morbidly obese patients, laboratory findings were not meaningfully different from those in normal-weight patients.

CONCLUSIONS

The obesity paradox of better outcomes in obese patients admitted to critical care units could not be explained on the basis of lower additional disease burden necessitating critical care admission due to abnormal laboratory values at the baseline. It is conceivable that unconscious bias against obese patients, with lower disease burden than normal-weight patients, triggers their admission to critical care, thus creating the appearance of better outcomes.

The Obesity Paradox: Body Mass Index Complication Rates Vary by Gender and Age Among Primary Total Hip Arthroplasty Patients

BACKGROUND

High body mass index (BMI) has long been recognized as a risk factor for postoperative complication among total hip arthroplasty (THA) patients. However, recent studies showed mixed results in the effect of high BMI on surgical outcomes. Our study is to examine the association of preoperative BMI with complication incidence, stratified by age and gender.

METHODS

We queried the American College of Surgeons National Surgical Quality Improvement Project database to identify patients who underwent elective primary THA between 2012 and 2016. We examined the associations between BMI as a continuous and a categorical variable and risk of 30-day postoperative complication, using 2 multiple polynomial logistic regression models. We also created predictive plots to graphically assess the relationship between BMI and complication by gender and age.

RESULTS

In total, 117,567 eligible patients were included in the analyses. The predictive probability of all-type postoperative complications showed a U-shaped relationship with continuous BMI values (range 10-65 kg/m²). The lowest complication risks occurred in patients with BMI between 35 and 40. Females had higher complication rate than males across all BMI values. This U-shaped relationship was only observed among patients younger than 60 years old, while the associations appear to be inversely linear among patients aged greater than 60 years.

CONCLUSION

Our results suggest that the current theory of a linear association between BMI and complication risk may not apply to elective primary THA. Strict BMI cutoffs may not minimize risk, especially among patients over 60 years old. Orthopedic surgeons should factor in patient-specific variables of age and gender when determining acceptable surgical risk given a particular BMI value.

Predictors of short-term readmission after beyond total mesorectal excision for primary locally advanced and recurrent rectal cancer

Unplanned readmissions heavily affect the cost of health care and are used as an indicator of performance. No clear data are available regarding beyond-total mesorectal excision (bTME) procedure. Aim of the study is to identify patient-related and surgery-related factors influencing the 30-day readmissions after bTME. Retrospective data were collected from 220 patients who underwent bTME procedures at single centre between 2006 and 2016. Patient-related and operative factors were assessed, including body mass index (BMI), age, gender, American Society of Anaesthesiologists' (ASA) score, preoperative stage, neo-adjuvant therapy, primary tumour vs recurrence, the extent of surgery. The readmission rate was 8.18%. No statistically significant association was found with BMI, ASA score, length of stay and stay in the intensive care unit, primary vs recurrent tumour or blood transfusions. Not quite statistically significant was the association with pelvic side wall dissection (OR 3.32, p = 0.054). Statistically significant factors included preoperative stage > IIIb (OR: 4.77, p = 0.002), neo-adjuvant therapy (OR: 0.13, p = 0.0006), age over 65 years (OR: 5.96, p = 0.0005), any re-intervention during the first admission (OR: 7.4, p = 0.0001), and any post-operative complication (OR: 9.01, p = 0.004). The readmission rate after beyond-TME procedure is influenced by patient-related factors as well as post-operative morbidity.