Impact of obesity on complications after resection for rectal cancer

The clinical predictive value of geriatric nutritional risk index in elderly rectal cancer patients received surgical treatment after neoadjuvant therapy

Objective

The assessment of nutritional status has been recognized as crucial in the treatment of geriatric cancer patients. The objective of this study is to determine the clinical predictive value of the geriatric nutritional risk index (GNRI) in predicting the short-term and long-term prognosis of elderly rectal cancer (RC) patients who undergo surgical treatment after neoadjuvant therapy.

Methods

Between January 2014 and December 2020, the clinical materials of 639 RC patients aged ≥70 years who underwent surgical treatment after neoadjuvant therapy were retrospectively analysed. Propensity score matching was performed to adjust for baseline potential confounders. Logistic regression analysis and competing risk analysis were conducted to evaluate the correlation between the GNRI and the risk of postoperative major complications and cumulative incidence of cancer-specific survival (CSS). Nomograms were then constructed for postoperative major complications and CSS. Additionally, 203 elderly RC patients were enrolled between January 2021 and December 2022 as an external validation cohort.

Results

Multivariate logistic regression analysis showed that GNRI [odds ratio = 1.903, 95% confidence intervals (CI): 1.120-3.233, p = 0.017] was an independent risk factor for postoperative major complications. In competing risk analysis, the GNRI was also identified as an independent prognostic factor for CSS (subdistribution hazard ratio = 3.90, 95% CI: 2.46-6.19, p < 0.001). The postoperative major complication nomogram showed excellent performance internally and externally in the area under the receiver operating characteristic curve (AUC), calibration plots and decision curve analysis (DCA). When compared with other models, the competing risk prognosis nomogram incorporating the GNRI achieved the highest outcomes in terms of the C-index, AUC, calibration plots, and DCA.

Conclusion

The GNRI is a simple and effective tool for predicting the risk of postoperative major complications and the long-term prognosis of elderly RC patients who undergo surgical treatment after neoadjuvant therapy.

Effect of obesity on perioperative outcomes following gastrointestinal surgery: meta-analysis

BACKGROUND

Obesity can pose perioperative challenges related to obesity-associated co-morbidities and technical factors. However, the true impact of obesity on postoperative outcomes is not well established and reports are conflicting. The aim was to perform a systematic review and meta-analysis to explore the effect of obesity on perioperative outcomes for general surgery procedures in distinct obesity subtypes.

METHODS

A systematic review was performed for studies reporting postoperative outcomes in relation to BMI in upper gastrointestinal, hepatobiliary and colorectal based on an electronic search using the Cochrane Library, Science Direct, PubMed and Embase up to January 2022. The primary outcome was the incidence of 30-day postoperative mortality among patients with obesity undergoing general surgical procedures in comparison to patients with normal range BMI.

RESULTS

Sixty-two studies, including 1 886 326 patients, were eligible for inclusion. Overall, patients with obesity (including class I/II/II) had lower 30-day mortality rates in comparison to patients with a normal BMI (odds ratio (OR) 0.75, 95 per cent c.i. 0.66 to 0.86, P < 0.0001, I2 = 71 per cent); this was also observed specifically in emergency general surgery (OR 0.83, 95 per cent c.i. 0.79 to 0.87, P < 0.0000001, I2 = 7 per cent). Compared with normal BMI, obesity was positively associated with an increased risk of 30-day postoperative morbidity (OR 1.11, 95 per cent c.i. 1.04 to 1.19, P = 0.002, I2 = 85 per cent). However, there was no significant difference in postoperative morbidity rates between the cohorts of patients with a normal BMI and class I/II obesity (OR 0.98, 95 per cent c.i. 0.92 to 1.04, P = 0.542, I2 = 92 per cent). Overall, the cohort with obesity had a higher rate of postoperative wound infections compared with the non-obese group (OR 1.40, 95 per cent c.i. 1.24 to 1.59, P < 0.0001, I2 = 82 per cent).

CONCLUSION

These data suggest a possible 'obesity paradox' and challenge the assumption that patients with obesity have higher postoperative mortality compared with patients with normal range BMI. Increased BMI alone is not associated with increased perioperative mortality in general surgery, highlighting the importance of more accurate body composition assessment, such as computed tomography anthropometrics, to support perioperative risk stratification and decision-making.

REGISTRATION NUMBER

CRD42022337442 (PROSPERO https://www.crd.york.ac.uk/prospero/).

Impact of obesity on patients undergoing surgery for rectal cancer in Australia and New Zealand

PURPOSE

Patients with obesity undergoing rectal cancer surgery may have an increased risk of developing complications, though evidence is inconclusive. The aim of this study was to determine the direct impact of obesity on postoperative outcomes using data from a large clinical registry.

METHOD

The Binational Colorectal Cancer Audit registry was used to identify patients who underwent rectal cancer surgery in Australia and New Zealand from 2007-2021. Primary outcomes were inpatient surgical and medical complications. Logistic regression models were developed to describe the association between body-mass index (BMI) and outcomes.

RESULTS

Among 3,708 patients (median age 66 years [IQR 56.75-75], 65.0% male), 2.0% had a BMI < 18.5 kg/m2, 35.4% had a BMI of 18.5-24.9 kg/m2, 37.6% had a BMI of 25.0-29.9 kg/m2, 16.7% had a BMI of 30.0-34.9 kg/m2, and 8.2% had a BMI ≥ 35.0 kg/m2. Surgical complications occurred in 27.7% of patients with a BMI of 18.5-24.9 kg/m2, 26.6% of patients with a BMI of 25.0-29.9 kg/m2 (OR 0.91, 95% CI 0.76-1.10), 28.5% with a BMI of 30.0-34.9 kg/m2 (OR 0.96, 95% CI 0.76-1.21), and 33.2% with a BMI ≥ 35.0 kg/m2 (OR 1.27, 95% CI 0.94-1.71). Modelling BMI as a continuous variable confirmed a J-shaped relationship. The association between BMI and medical complications was more linear.

CONCLUSION

Risk of postoperative complications is increased in patients with obesity undergoing rectal cancer surgery.

A meta-analysis of the effect of different body mass index on surgical wound infection after colorectal surgery

We conducted a meta-analysis to assess the effect of different body mass index on surgical wound infection after colorectal surgery. A systematic literature search up to November 2022 was performed and 2349 related studies were evaluated. The chosen studies comprised 15 595 colorectal surgery subjects participated in the selected studies' baseline trials; 4390 of them were obese according to the selected body mass index cut-off used to measure obesity in the selected studies, while 11 205 were nonobese. Odds ratio (OR) with 95% confidence intervals (CIs) were calculated to assess the effect of different body mass index on wound infection after colorectal surgery by the dichotomous methods with a random or fixed effect model. The body mass index ≥30 kg/m² resulted in significantly higher surgical wound infection after colorectal surgery (OR, 1.76; 95% CI, 1.46-2.11, P < .001) compared with the body mass index <30 kg/m² . The body mass index ≥25 kg/m² resulted in significantly higher surgical wound infection after colorectal surgery (OR, 1.64; 95% CI, 1.40-1.92, P < .001) compared with the body mass index <25 kg/m² . The subjects with higher body mass index had a significantly higher surgical wound infection after colorectal surgery compared with the subjects with normal body mass index.

Impact of obesity on morbidity and oncologic outcomes after total mesorectal excision for mid and low rectal cancer

BACKGROUND

A recent meta-analysis showed that obesity increased the conversion rate and postoperative morbidity of rectal cancer surgery, but did not influence pathological results. However, this meta-analysis included patients with cancer of the upper rectum and had many biases. The aim of the present retrospective study was to investigate the impact of obesity, defined as a body mass index (BMI) ≥ 30 kg/m², on postoperative morbidity and short- and long-term oncologic outcomes of total mesorectal excision for mid and low rectal cancer in consecutive patients.

METHODS

This study included all eligible patients who were operated on for mid and lower rectal cancer between 1999 and 2018 in our hospital. We compared 90-day postoperative morbidity and mortality, and short- and long-term oncologic outcomes between obese and non-obese patients.

RESULTS

Three hundred and ninety patients [280 males, mean age 65.7 ± 11.3 years, 59 obese individuals (15.1%)] were included. There was no difference in the 90-day mortality rate between obese and non-obese groups (p = 0.068). There was a difference in the overall 90-day morbidity rate between the obese and non-obese groups that disappeared after propensity score matching of the patients. There was no difference in short-term oncological parameters, with a median follow-up of 43 (20-84) months, and there were no significant differences in disease-free and overall survival between obese and non-obese patients (p = 0.42 and p = 0.11, respectively).

CONCLUSIONS

Obesity does not affect the 90-day morbidity rate, or short- and long-term oncologic results in patients operated on for mid and lower rectal cancer.

Effect of body mass index on surgical site wound infection, mortality, and postoperative hospital stay in subjects undergoing possibly curative surgery for colorectal cancer: A meta-analysis

We performed a meta-analysis to evaluate the effect of body mass index on surgical site wound infection, mortality, and postoperative hospital stay in subjects undergoing possibly curative surgery for colorectal cancer. A systematic literature search up to March 2022 was performed and 2247 subjects with possibly curative surgery for colorectal cancer at the baseline of the studies; 2889 of them were obese, and 9358 were non-obese. Odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated to assess the effect of body mass index on surgical site wound infection, mortality, and postoperative hospital stay in subjects undergoing possibly curative surgery for colorectal cancer using the dichotomous or contentious methods with a random or fixed-effect model. The obese subjects had a significantly higher surgical site wound infection after colorectal surgery (OR, 1.87; 95% CI, 1.62-2.15, P < .001), and higher mortality (OR, 1.58; 95% CI, 1.07-2.32, P = .02) in subjects with possibly curative surgery for colorectal cancer compared with non-obese. However, obese did not show any significant difference in postoperative hospital stay (MD, 0.81; 95% CI, -0.030 to 1.92, P = .15) compared with non-obese in subjects with possibly curative surgery for colorectal cancer. The obese subjects had a significantly higher surgical site wound infection after colorectal surgery, higher mortality, and no significant difference in postoperative hospital stay compared with non-obese in subjects with possibly curative surgery for colorectal cancer. The analysis of outcomes should be with caution because of the low number of studies in certain comparisons.

Oncologic Status of Obturator Lymph Node Metastases in Locally Advanced Low Rectal Cancer: A Japanese Multi-Institutional Study of 3487 Patients

BACKGROUND

The American Joint Committee on Cancer tumor-node-metastasis staging system for rectal cancer defines lateral pelvic lymph nodes (LPLNs) only in the internal iliac region as regional. However, the Japanese Society for Cancer of the Colon and Rectum (JSCCR) staging system, also considers obturator lymph nodes (LNs) as regional. This retrospective cohort study evaluated the oncologic status of obturator LNs in low rectal cancer.

METHODS

The study identified 3487 patients with pT3-T4 low rectal cancer who had undergone curative resections without preoperative radiotherapy or chemotherapy between 2003 and 2011 in the JSCCR database and divided them into six groups. Overall survival (OS) and recurrence-free survival (RFS) were analyzed by groups.

RESULTS

Histologic LPLN metastases were identified in 8% (279/3487) of all the patients and in 18.2% (279/1530) of the patients who underwent lateral pelvic node dissection. The 5-year OS and RFS rates of the obturator-LPLN group (P = 0.095) were worse than those of the internal-LPLN group (P = 0.075), but the difference was not significant. The OS of the obturator-LPLN group was similar to that of the resectable liver metastasis group (P = 0.731), and the RFS of the obturator-LPLN group was significantly better than that of the other-LPLN group (P = 0.016).

CONCLUSION

The prognosis for obturator LN metastases in low rectal cancer was not significantly worse than for internal iliac LN metastases, defined as regional by the current American Joint Committee on Cancer staging system, and the oncologic status of obturator LNs warrants more studies.

Risk Factors for Prolonged Postoperative Ileus in Colorectal Surgery: A Systematic Review and Meta-analysis

BACKGROUND

Prolonged postoperative ileus (PPOI) represents a frequent complication following colorectal surgery, affecting approximately 10-15% of these patients. The objective of this study was to evaluate the perioperative risk factors for PPOI development in colorectal surgery.

METHODS

The present systematic review and meta-analysis was conducted in accordance with the PRISMA Statement. PubMed, EMBASE, SciELO, and LILACS databases were searched, without language or time restrictions, from inception until December 2018. The keywords used were: Ileus, colon, colorectal, sigmoid, rectal, postoperative, postoperatory, surgery, risk, factors. The Newcastle-Ottawa scale and the Jadad scale were used for bias assessment, while the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used for quality assessment of evidence on outcome levels.

RESULTS

Of the 64 studies included, 42 were evaluated in the meta-analysis, comprising 29,736 patients (51.84% males; mean age 62 years), of whom 2844 (9.56%) developed PPOI. Significant risk factors for PPOI development were: male sex (OR 1.43; 95% CI 1.25-1.63), age (MD 3.17; 95% CI 1.63-4.71), cardiac comorbidities (OR 1.54; 95% CI 1.19-2.00), previous abdominal surgery (OR 1.44; 95% CI 1.19, 1.75), laparotomy (OR 2.47; 95% CI 1.77-3.44), and ostomy creation (OR 1.44; 95% CI 1.04-1.98). Included studies evidenced a moderate heterogeneity. The quality of evidence was regarded as very low-moderate according to the GRADE approach.

CONCLUSIONS

Multiple factors, including demographic characteristics, past medical history, and surgical approach, may increase the risk of developing PPOI in colorectal surgery patients. The awareness of these will allow a more accurate assessment of PPOI risk in order to take measures to decrease its impact on this population.

Comparison of Outcomes between Obese and Non-Obese Patients in a Colorectal Enhanced Recovery After Surgery (ERAS) Program: A Single-Center Cohort Study

INTRODUCTION

Obese patients are considered at increased risk of postoperative adverse events after colorectal surgery.

OBJECTIVE

The objective of the present study was to compare postoperative outcomes between obese and non-obese patients undergoing elective colorectal surgery in an Enhanced Recovery After Surgery (ERAS) program.

METHODS

A retrospective analysis of a prospective cohort including patients who underwent elective colorectal surgery and were included in an ERAS protocol between February 2014 and December 2017 at Geneva University Hospital, Geneva, Switzerland, was performed. Postoperative outcomes of obese and non-obese patients were compared.

RESULTS

Data of 460 patients were analyzed, including 374 (81%) non-obese and 86 (19%) obese patients. Overall, there was no difference in postoperative outcomes between the 2 groups. Among patients undergoing oncologic surgery, obese subjects had a significantly higher rate of conversion to laparotomy (11.9 vs. 2.1%, p = 0.01) and longer time until return of bowel function (2.38 vs. 1.98 days, p = 0.03), without increased morbidity or longer length of stay.

CONCLUSION

Obese and non-obese patients had similar postoperative outcomes after elective colorectal surgery with ERAS management. ERAS can potentially reduce the increased morbidity usually observed in obese patients following elective colorectal surgery.

Influence of Body Mass Index on Long-Term Outcome in Patients with Rectal Cancer-A Single Centre Experience

BACKGROUND

Excess bodyweight is known to influence the risk of colorectal cancer; however, little evidence exists for the influence of the body mass index (BMI) on the long-term outcome of patients with rectal cancer.

METHODS

We assessed the impact of the BMI on the risk of local recurrence, distant metastasis and overall-survival in 612 patients between 2003 and 2010 after rectal cancer diagnosis and treatment at the University Hospital Erlangen. A Cox-regression model was used to estimate the hazard ratio and multivariate risk of mortality and distant-metastasis. Median follow up-time was 58 months.

RESULTS

Patients with obesity class II or higher (BMI ≥ 35 kg/m², n = 25) and patients with underweight (BMI < 18.5 kg/m², n = 5) had reduced overall survival (hazard ratio (HR) = 1.6; 95% confidence interval (CI) 0.9-2.7) as well as higher rates of distant metastases (hazard ratio HR = 1.7; 95% CI 0.9-3.3) as compared to patients with normal bodyweight (18.5 ≤ BMI < 25 kg/m², n = 209), overweight (25 ≤ BMI <30 kg/m², n = 257) or obesity class I (30 ≤ BMI <35 kg/m², n = 102). There were no significant differences for local recurrence.

CONCLUSIONS

Underweight and excess bodyweight are associated with lower overall survival and higher rates of distant metastasis in patients with rectal cancer.

The effect of increasing body mass index on laparoscopic surgery for colon and rectal cancer

AIM

Obesity is common in Western countries and its prevalence is increasing. Colorectal cancer is common, and surgery for colorectal cancer is technically more challenging in obese patients. Laparoscopic surgery for colon cancer has been shown to be oncologically equivalent, with improved short- term outcomes. Laparoscopic surgery for rectal cancer has proven technically challenging, and recent results have raised concerns about oncological equivalence. Our aim was to evaluate the effect of body mass index (BMI) on the clinical and oncological outcomes of surgery for colorectal cancer, including the rate at which laparoscopic surgery is attempted and the rate at which laparoscopic surgery is converted to open surgery.

METHOD

A retrospective analysis of prospectively collected data from two tertiary institutions was performed. Data were obtained from the Cabrini Monash University colorectal neoplasia database for patients having surgical resection for colon and rectal cancers between 1 January 2010 and 30 June 2015. Surgical and medical complications, tumour recurrence and overall survival and laparoscopic surgery and conversion rates were investigated.

RESULTS

This large case series of 1464 patients undergoing elective surgery for colorectal cancer has demonstrated that an elevated BMI is associated with a lower likelihood of attempting laparoscopic surgery and a higher conversion rate to open surgery when laparoscopy is attempted. Conversion was 1.9 times more likely in obese patients with colon cancer and 4.1 times more likely in obese patients with rectal cancer. The critical BMI for colon cancer patients was > 35 kg/m² , and for rectal cancer patients > 30 kg/m² . Obesity is also associated with increased rates of surgical complications, including anastomotic leakage and wound complications. Pathological parameters, tumour recurrence and survival were not affected by elevated BMI.

CONCLUSION

In the surgical management of colorectal cancer, obesity is associated with a lower likelihood of laparoscopic surgery being attempted, a higher likelihood of conversion to open surgery when laparoscopic surgery is attempted, and a higher rate of surgical complications.

Visceral fat area, not body mass index, predicts postoperative 30-day morbidity in patients undergoing colon resection for cancer

PURPOSE

Colectomy for cancer in obese patients is technically challenging and may be associated with worse outcomes. Whether visceral obesity, as measured on computed tomography, is a better predictor of complication than body mass index (BMI) or determines long-term oncologic outcomes has not been well characterized. This study examines the association between derived anthropometrics and postoperative complication and long-term oncologic outcomes.

METHODS

Retrospective review of patients undergoing elective colectomy for cancer at a single tertiary-care center from 2010 to 2016. Adipose tissue distribution measurements, including visceral fat area (VFA), were determined from preoperative imaging. The primary outcome was 30-day postoperative complication; secondary outcomes included overall and disease-free survival. Multivariable logistic regression was performed to determine association between obesity metrics and outcome.

RESULTS

Two hundred and sixty-four patients underwent 266 primary resections of colon cancer. Twenty-eight patients (10.5%) developed major morbidity (Clavien-Dindo grade ≥ III). VFA but not BMI was significantly associated with morbidity in multivariate analysis (p = 0.004, odds ratio 1.99, 95% confidence interval 1.25-3.19). No other imaging-derived anthropometric was associated with increased morbidity. In receiver operating characteristic analysis, VFA was predictive of major morbidity (area under curve 0.660). A cutoff value of VFA ≥ 191 cm² was associated with 50% sensitivity and 76% specificity for predicting major morbidity. Patients with VFA ≥ 191cm² had 19.4% risk of morbidity, whereas those with < 191 cm² had 7.2% risk (relative risk ratio 2.69, unadjusted p = 0.004). Neither VFA nor BMI was associated with overall or disease-free survival.

CONCLUSION

VFA but not BMI predicts morbidity following elective surgery for colon cancer.

Does obesity impact postoperative outcomes following robotic-assisted surgery for rectal cancer?

INTRODUCTION

Obesity has been identified as a risk factor for both conversion and severe postoperative morbidity in patients undergoing laparoscopic rectal resection. Robotic-assisted surgery (RAS) is proposed to overcome some of the technical limitations associated with laparoscopic surgery for rectal cancer. The aim of our study was to determine if obesity remains a risk factor for severe morbidity in patients undergoing robotic-assisted rectal resection.

PATIENTS

This study was a retrospective review of a prospective database. A total of 183 patients undergoing restorative RAS for rectal cancer between 2007 and 2016 were divided into 2 groups: control (BMI < 30 kg/m²; n = 125) and obese (BMI ≥ 30 kg/m²; n = 58). Clinicopathologic data, 30-day postoperative morbidity, and perioperative outcomes were compared between groups. The main outcome was severe postoperative morbidity defined as any complication graded Clavien-Dindo ≥ 3.

RESULTS

Control and obese groups had similar clinicopathologic characteristics. Severe complications were observed in 9 (7%) and 4 (7%) patients, respectively (p > 0.99). Obesity did not impact conversion, anastomotic leak rate, length of stay, or readmission but was significantly associated with increased postoperative morbidity (29 vs. 45%; p = 0.04) and especially more postoperative ileus (11 vs. 26%; p = 0.01). Obesity and male gender were the two independent risk factors for postoperative overall morbidity (OR 1.97; 95% CI 1.02-3.94; p = 0.04 and OR 2.23; 95% CI 1.10-4.76; p = 0.03, respectively).

CONCLUSION

‎Obesity did not impact severe morbidity or conversion rate following RAS for rectal cancer but remained a risk factor for overall morbidity and especially postoperative ileus.

The relationship between body mass index and short term postoperative outcomes in patients undergoing potentially curative surgery for colorectal cancer: A systematic review and meta-analysis

BACKGROUND

The prevalence of obesity has increased worldwide over the last few decades, and is a well-recognized risk factor for colorectal cancer. Surgical site infection is the most frequent complication following surgery for colorectal cancer, and the main cause of postoperative morbidity. The aim of the present systematic review and meta-analysis was to examine the relationship between increasing BMI and postoperative surgical site infection following surgery for colorectal cancer.

METHODS

A systemic literature search was conducted using Medline, PubMed, Embase (Ovid) and Web of Science databases from inception to the end of August 2016. Studies examining the relationship between obesity and surgical site infection following surgery for colorectal cancer were included. Analysis of the data was performed using Review Manager version 5.3(The Nordic Cochrane Centre, The Cochrane Collaboration, Copen-hagen, Denmark,) RESULTS: In this meta-analysis, a total of 9535 patients from 16 studies were included. BMI <30 vs ≥30kg/m² was used to examine the association of obesity and surgical site infection in patients from Western countries. The estimated pooled OR demonstrated that obesity increased the risk of surgical site infection by approximately 100% (OR=2.13; 95% CI 1.66-2.72, p<0.001).BMI <25 vs ≥25kg/m² was used to examine the association of obesity and surgical site infection from Asian countries. The estimated pooled OR demonstrated that obesity increased the risk of surgical site infection by approximately 60% (OR=1.63; 95% CI 1.29-2.06, p<0.001). There was little evidence of publication bias in the meta-analysis.

CONCLUSION

From this systematic review and meta-analysis there was good evidence that obesity was associated with a significantly higher risk of developing surgical site infection following surgery for colorectal cancer in both ethnic groups. The magnitude of the effect warrants further investigation.

Impact of Body Mass Index on Early Postoperative and Long-Term Outcome after Rectal Cancer Surgery

Background

The aim of this study was to investigate the impact of obesity and underweight onto early postoperative and long-term oncological outcome after surgery for rectal cancer.

Methods

Data from 2008 until 2011 was gathered by a German prospective multicenter observational study. 62 items were reported by the physicians in charge, and a consecutive follow-up was performed if the patient had signed a consent form. Patients were subclassified into: underweight, normal weight, overweight, and obese - using the definitions of the World Health Organization.

Results

In total, 9,920 patients were included, of whom 2.1% were underweight and 19.4% obese. The mean age was 68 years (range 21-99 years). Postoperative morbidity (mean 38.0%) was significantly increased in underweight and obese patients (p < 0.001). In-hospital mortality was 3.1% on average with no significant differences among patient groups (p = 0.176). The 5-year overall survival ranged between 36.9 and 61.3% and was worse in underweight and prolonged in overweight and obese patients compared to those with normal weight (p < 0.001 each). While the 5-year disease-free survival was increased in overweight and obese patients (p < 0.05 each), the 5-year local recurrence rate showed no correlation (p > 0.05 each). Multivariate analysis revealed that advanced age, higher ASA scoring, postoperative morbidity, and advanced tumor growth worsened the long-term survival independently.

Conclusions

Underweight patients had a worse early and long-term outcome after rectal cancer surgery. Overweight and obesity were associated with a significantly better long-term survival.

Meta-analysis of the clinicopathological characteristics and peri-operative outcomes of colorectal cancer in obese patients

BACKGROUND

The effect of obesity on the clinicopathological characteristics of colorectal cancer (CRC) has not been clearly characterized. This meta-analysis assesses the pathological and perioperative outcomes of obese patients undergoing surgical resection for CRC.

METHODS

Meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Databases were searched for studies reporting outcomes for obese and non-obese patients undergoing primary CRC resection, based on body-mass index measurement. Results were reported as mean differences or pooled odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

A total of 2183 citations were reviewed; 29 studies comprising 56,293 patients were ultimately included in the analysis, with an obesity rate of 19.3%. Obese patients with colorectal cancer were more often female (OR 1.2, 95% CI 1.1-1.2, p<0.001) but there was no difference in the proportion of rectal cancers, T4 tumours, tumour differentiation or margin positivity. Obese patients were significantly more likely to have lymph node metastases (OR 1.2, 95% CI 1.1-1.2, p<0.001), have a lower nodal yield, were associated with a longer duration of surgery, more blood loss and conversions to open surgery (OR 2.6, 95% CI 1.6-4.0, p<0.001) but with no difference in length of stay or post-operative mortality.

CONCLUSION

This meta-analysis demonstrates that obese patients undergoing resection for CRC are more likely to have node positive disease, longer surgery and higher failure rates of minimally invasive approaches. The challenges of colorectal cancer resection in obese patients are emphasized.

How to Manage the Obese Patient With Cancer

Purpose

Obesity (body mass index [BMI] ≥ 30 kg/m2) is common among patients with cancer. We reviewed management issues in the obese patient with cancer, focusing on how obesity influences treatment selection (including chemotherapy dosing), affects chemotherapy toxicity and surgical complications, and might be a treatment effect modifier.

Methods

The majority of evidence is drawn from observational studies and secondary analyses of trial data, typically analyzed in N × 3 BMI categories (normal weight, overweight, and obese) matrix structures. We propose a methodological framework for interpretation focusing on sample size and composition, nonlinearity, and unmeasured confounding.

Results

There is a common perception that obesity is associated with increased treatment-related toxicity. Accordingly, cytotoxic chemotherapy dose reduction is common in patients with elevated BMI. Contrary to this, there is some evidence that full dosing in obese patients does not result in increased toxicity. However, these data are from a limited number of regimens, and fail to fully capture cytotoxic drug pharmacodynamics and pharmacokinetic variability in obese patients. Among patients undergoing surgery, there is evidence that elevated BMI is associated with increased perioperative mortality and increased rates of infectious complications. A novel finding is that these relationships hold after surgery for malignancy, but not for benign indications. There are biologic plausibilities that obesity might be an effect modifier of treatment, but supporting evidence from clinical studies is inconsistent.

Conclusion

In line with the ASCO 2012 guidelines, chemotherapy dosing is probably best performed using actual body weight in obese patients. However, specific regimens known to be associated with increased toxicity in this group should be used with caution. There is no guidance on dose for obese patients treated with biologic agents. Currently, there are no specific recommendations for the surgical management of the obese patient with cancer.

Outcome of rectal cancer surgery in obese and nonobese patients: a meta-analysis

Background

The escalating global epidemic of obesity is of worldwide concern because of its association with serious negative effects on health. The technical difficulty of rectal cancer surgery is exacerbated in obese patients, which may compromise outcomes. High-quality, relevant evidence is limited. This meta-analysis aims to assess the outcomes of rectal cancer surgery in obese and nonobese patients.

Methods

The electronic databases Pubmed, Medline, Embase, Web of Science, and the Cochrane Library were used to search for articles that evaluated the outcomes of rectal cancer surgery in obese and nonobese patients. Fixed-effects and random-effects models were used to calculate the combined overall effect sizes of pooled data. Data are presented as odds ratios (OR) or weighted mean differences (WMD) with 95 % confidence intervals (CIs).

Results

Ten appropriate observational studies were identified from 290 published articles. In the obese group, conversion rates (OR 2.78; 95 % CI 1.67–4.61), overall morbidity (OR 1.36; 95 % CI 1.25–1.47), anastomotic leak (OR 3.94; 95 % CI 1.88–8.24), wound infection (OR 2.22; 95 % CI 1.47, 3.36), and pulmonary events (OR 2.10; 95 % CI 1.18, 3.74) were all significantly increased. For pathological results, no statistical differences in the number of harvested lymph nodes and the positive margin were noted between the two groups.

Conclusions

Based on a meta-analysis, obesity increases the conversion rate and postoperative morbidity of rectal cancer surgery but does not influence pathological results.

Outcome of rectal cancer surgery in obese and nonobese patients: a meta-analysis

BACKGROUND

The escalating global epidemic of obesity is of worldwide concern because of its association with serious negative effects on health. The technical difficulty of rectal cancer surgery is exacerbated in obese patients, which may compromise outcomes. High-quality, relevant evidence is limited. This meta-analysis aims to assess the outcomes of rectal cancer surgery in obese and nonobese patients.

METHODS

The electronic databases Pubmed, Medline, Embase, Web of Science, and the Cochrane Library were used to search for articles that evaluated the outcomes of rectal cancer surgery in obese and nonobese patients. Fixed-effects and random-effects models were used to calculate the combined overall effect sizes of pooled data. Data are presented as odds ratios (OR) or weighted mean differences (WMD) with 95% confidence intervals (CIs).

RESULTS

Ten appropriate observational studies were identified from 290 published articles. In the obese group, conversion rates (OR 2.78; 95% CI 1.67-4.61), overall morbidity (OR 1.36; 95% CI 1.25-1.47), anastomotic leak (OR 3.94; 95% CI 1.88-8.24), wound infection (OR 2.22; 95% CI 1.47, 3.36), and pulmonary events (OR 2.10; 95% CI 1.18, 3.74) were all significantly increased. For pathological results, no statistical differences in the number of harvested lymph nodes and the positive margin were noted between the two groups.

CONCLUSIONS

Based on a meta-analysis, obesity increases the conversion rate and postoperative morbidity of rectal cancer surgery but does not influence pathological results.

Kidney Transplantation Significantly Improves Patient and Graft Survival Irrespective of BMI: A Cohort Study

Obesity and end-stage renal disease (ESRD) are on the increase worldwide. Kidney transplantation is the treatment of choice for ESRD. However, obesity is considered a contraindication for transplantation. We investigated the effect of BMI on mortality in transplanted and patients remaining on the waiting list in the United Kingdom. We analyzed the UK Renal Registry (RR) and the National Health Service Blood and Transplant (NHSBT) Organ Donation and Transplantation data for patients listed from January 1, 2004 to December 31, 2010, with follow-up until December 31, 2011. Seventeen thousand six hundred eighty-one patients were listed during the study period, with BMI recorded for 13 526 (77%). One- and five-year patient survival was significantly better in all BMI bands (<18.5, 18.5-<25, 25-<30, 30-<35, 35-<40, and 40+kg/m(2) ) in the transplant group when compared to those who remained on the waiting list (p < 0.0001). The analyses were repeated excluding live donor transplants and the results were essentially the same. On analyses of patient survival with BMI as a continuous variable or using 5 kg weight bands, there was no cut-off observed in the higher BMI patients where there would be no benefit to transplantation. For transplanted patients (N = 8088), there was no difference in patient or graft survival between the defined BMI bands. Thus, irrespective of BMI, patient survival is improved if transplanted.

Influence of Obesity on Anastomotic Leakage After Anterior Rectal Resectionperformed Due to Cancer

Anterior resection for rectal cancer carries the risk of serious complications, especially fistulas at the site of anastomosis. Numerous factors have been shown to impact anastomotic leakage. The results of studies on the influence of obesity on the frequency of anastomotic leakage after rectal resection performed due to cancer have been contradictory. The aim of the study was to evaluate the relationship between body mass index (BMI) and frequency of anastomotic leakage after anterior rectal resection performed due to cancer.

MATERIAL AND METHODS

This retrospective analysis included 222 subsequent patients who had undergone anterior resection due to cancer with an anastomosis formed with a mechanical suture. The patients were divided into 3 groups depending on their BMI quartile as follows: Group I, BMI < 23.8 kg/m2 (lower quartile); group II, BMI between 23.8 and 29.38 kg/m2 (middle quartile); and group III, BMI > 29.38 kg/m2 (upper quartile).

RESULTS

Anastomotic leakage occurred in 8 (3.6%) patients. Fistulas occurred in 4 out of 61 patients (6.56%) in group I, which was the highest incidence of fistulas for all 3 groups. In group II, fistulas occurred in 2 out of 55 patients (3.63%), and similarly, in group III, they occurred in 2 out of 106 patients (1.87%). The differences found in the frequency of fistulas between groups were not statistically significant (p=0.31). The logistic regression analysis did not show any relationship between leakage and age (p = 0.55; OR = 1.02; 95% CI: 0.95 - 1.1), sex (p = 0.97; OR = 0.97; 95% CI: 0.22 - 4.25) or BMI (p = 0.27; OR = 0.58; 95% CI: 0.22 - 1.53).

CONCLUSIONS

The results of our study show that BMI did not have any influence on the frequency of anastomotic leakage after anterior rectal resection performed due to cancer.

Influence of body mass index on outcomes after major resection for cancer

BACKGROUND

Evidence supporting worse outcomes among obese patients is inconsistent. This study examined associations between body mass index (BMI) and outcomes after major resection for cancer.

METHODS

Data from the 2005-2012 ACS-NSQIP were used to identify cancer patients (≥18 years) undergoing 1 of 6 major resections: lung surgery, esophagectomy, hepatectomy, gastrectomy, colectomy, or pancreatectomy. We used crude and multivariable regression to compare differences in 30-day mortality, serious and overall morbidity, duration of stay, and operative time among 3 BMI cohorts defined by the World Health Organization: normal versus underweight, overweight-obese I, and obese II-III. Propensity-scored secondary assessment and resection type-specific stratified analyses corroborated results.

RESULTS

A total of 529,955 patients met inclusion criteria; 32.06% had normal BMI, 3.45% were underweight, 32.52% overweight, and 17.76%, 7.51%, and 4.94% obese I-III, respectively. Risk-adjusted outcomes for underweight patients consistently were worse. Overweight-obese I fared similarly to patients with normal BMI but had greater odds of isolated complications. Obese II-III patients experienced only marginally increased odds of morbidity. Analyses among propensity-scored cohorts and stratified by cancer-resection type reported similar trends. Worse outcomes were observed among morbidly obese hepatectomy and pancreatectomy patients.

CONCLUSION

Evidence-based assessment of outcomes after major resection for cancer suggests that obese patients should be treated with the aim for optimal oncologic standards without being hindered by a misleading perception of prohibitively increased perioperative risk. Underweight and certain types of morbidly obese patients require targeted provision of appropriate care.