Association of obesity with postoperative outcomes after proctectomy

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.

The safety and prognosis of radical surgery in colorectal cancer patients over 80 years old

OBJECTIVE

The purpose of this study was to assess the safety and feasibility of radical surgery and to investigate prognostic factors influencing in colorectal cancer (CRC) patients over the age of 80.

METHODS

Between January 2010 and December 2020, 372 elderly CRC patients who underwent curative resection at the National Cancer Center were enrolled in the study. Preoperative clinical characteristics, perioperative outcomes, and postoperative pathological features were all collected.

RESULTS

A total of 372 elderly patients with colorectal cancer were included in the study, including 226 (60.8%) men and 146 (39.2%) women. A total of 219 (58.9%) patients had a BMI < 24 kg/m², and 153 (41.1%) patients had a BMI ≥ 24 kg/m². The mean operation time and intraoperative blood loss were 152.3 ± 58.1 min and 67.6 ± 35.4 ml, respectively. The incidence of overall postoperative complications was 28.2% (105/372), and the incidence of grade 3-4 complications was 14.7% (55/372). In the multivariable Cox regression analysis, BMI ≥ 24 kg/m² (HR, 2.30, 95% CI, 1.27-4.17; P = 0.006) and N1-N2 stage (HR: 2.97; 95% CI, 1.48-5.97; P = 0.002) correlated with worse CSS.

CONCLUSION

The findings of this study showed that radical resection for CRC is safe and feasible for patients over the age of 80. After radical resection, BMI and N stage were independent prognostic factors for elderly CRC patients.

The impact of sarcopenic obesity on treatment outcomes in gastrointestinal cancer: A systematic review

BACKGROUND

GI tract cancer includes a broad spectrum of tumors with generally high prevalence and poor prognosis. Over the past decade sarcopenia (skeletal muscle depletion), myosteatosis, sarcopenic obesity were all shown to have a negative prognostic impact in patients with various malignancies. However, the role of sarcopenic obesity (SO) in patients with GI tumors remains controversial. We systematically reviewed data on the prevalence and prognostic impact of SO for patients with GI malignancies, undergoing surgical and/or chemotherapeutical treatment.

METHODS

This study was conducted in adherence to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. PubMed and Cochrane Library were searched for relevant original studies published between January 2008 to December 2020 reporting postoperative morbidity and mortality, long-term survival and toxicity after chemotherapeutical treatment in SO patients with GI cancer.

RESULTS

Twenty-two studies comprising 8571 patients were included. The percentage of SO patients ranged from 2.6% to 51%. The association between SO and outcomes of interest was inconsistent because of various cut-offs used to define sarcopenia and obesity. However, SO was significantly associated with the occurrence of major postoperative complications in five studies. In contrast, three studies did not show the impact of SO on postoperative complications. Three studies demonstrated that mortality rate was significantly higher among patients with SO. Five studies of systematic review revealed a statistically significant influence of SO on overall survival in multivariate analysis. However, only in one of them a significant difference was found between SO and DFS. Three studies evaluated toxicity after chemotherapy and all reported statistically significant negative impact of SO.

CONCLUSIONS

There is considerable heterogeneity in methods used to define SO in the literature and current data is limited. Standardized terminology and deeper understanding of sarcopenic obesity pathophysiology is needed to further understand the influence of obesity and sarcopenia on the clinical trajectory of patients with GI cancer.

The impact of obesity on minimally invasive colorectal surgery: A report from the Surgical Care Outcomes Assessment Program collaborative

BACKGROUND

Operating on obese patients can increase case complexity and result in worse outcomes. We described the incremental impact of BMI on morbidity and outcomes of colorectal operations and whether laparoscopic and robotic(MIS) approaches mitigate this morbidity differently.

METHODS

A retrospective cohort of patients undergoing elective colorectal operations in SCOAP was created to examine the association of increasing BMI on surgical outcomes. Additionally, multivariable logistic regression models were constructed.

RESULTS

From 2011 to 2019, 22,863 elective colorectal operations (mean age 62, 55% female) were performed at 42 hospitals. Patients had BMI≥30 in 7576(33%) and BMI≥40 in 1180(5%) of operations. After risk adjustment, BMI≥40 was associated with increased conversions(OR1.57,95%CI1.26-1.96), increased combined adverse events(CAE)(OR1.32,95%CI1.15-1.52), and death(OR2.24, 95%CI1.41-3.55)(all p < 0.01). MIS approaches were each associated with lower CAE(lap OR0.49,95%CI0.46-0.53; robot OR0.42,95%CI0.37-0.47), and death(lap OR0.24,95%CI0.18-0.33; robot OR0.18,95%CI0.10-0.35)(all p < 0.01).

CONCLUSIONS

Severe obesity is associated with increased conversion rates and worse short-term outcomes after colorectal surgery, though this trend is partially mitigated with a minimally invasive approach. These findings support the broad application of MIS for colorectal operations in obese patients.

Pathologic complete response is associated with decreased morbidity following rectal cancer resection

BACKGROUND

There are conflicting data regarding the relationship between pathologic complete response (pCR) and post-operative complications following rectal cancer resection. The objective of this study was to compare the rates of morbidity among pCR patients and non-pCR patients and to identify factors that predict pCR morbidity in a large national database.

METHODS

This is a retrospective study using American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) targeted proctectomy data (2016-18). Patients with neoadjuvant chemoradiation therapy followed by proctectomy were included, and divided into pCR and non-pCR groups according to final stage. The groups were compared with Student's t-test, Chi-squared or Fisher's exact test. Multivariate logistic regression models were constructed to estimate the association between pCR status and post-operative morbidity while adjusting for key covariates.

RESULTS

244 pCR and 1656 non-pCR patients were included. pCR patients had higher body mass index (28.1 ± 6.2 vs. 29.1 ± 5.9 kg/m²; p = 0.01) and lower pre-operative stage (T stage, p = 0.03; N stage, p < 0.001). The groups were equivalent with respect to surgical approach, type of surgery, and operative time (p > 0.05). Post-operative complications in pCR patients were less frequent than in non-pCR patients (23.0% vs. 29.3%; p = 0.04). This association was robust to adjustment for confounders in logistic regression, as patients with pCR had decreased odds of post-operative morbidity (OR 0.66, CI [0.43, 0.96], p = 0.04).

CONCLUSION

pCR is associated with fewer post-operative complications compared to non-pCR, suggesting that pCR is not a marker of severe pelvic fibrosis. This difference may be due to underlying tumor biology, and associated increased technical challenges resecting larger, non-responsive tumors.

BMI May Be a Prognostic Factor for Local Advanced Rectal Cancer Patients Treated with Long-Term Neoadjuvant Chemoradiotherapy

OBJECTIVE

This study aims to develop feasible nomograms to predict the overall survival (OS) and cancer-specific survival (CSS) of the local advanced rectal cancer (LARC) patients who were treated with neoadjuvant chemoradiotherapy (nCRT) and operation.

METHODS

A total of 243 LARC patients undergoing nCRT followed by total mesorectal excision (TME) were enrolled. Preoperative clinical features and postoperative pathological characteristics were collected. A Cox regression analysis was performed, and Cox-based nomograms were developed to predict the OS and CSS. We assessed the predictive performance of the nomogram with concordance index and calibration plots.

RESULTS

A total of 243 patients were included with a median follow-up period of 46 months (range from 9 to 86 months). Cox regression analysis showed that low BMI (BMI < 18.5, HR= 21.739, P < 0.05), high level of preoperative CA19-9 (HR = 3.369, P = 0.036), high ypStage (HR = 19.768, P < 0.001), positive neural invasion (HR = 4.218, P = 0.026) and no adjuvant chemotherapy (HR = 5.495, P < 0.001) were independent predictors of poor OS. Age ≥70 (HR = 2.284, P <0.001), low BMI (BMI < 18.5, HR = 3.906, P < 0.05), positive preoperative CA19-9 (HR = 1.920, P = 0.012), high ypStage (HR = 5.147, P <0.001) and positive neural invasion (HR = 2.873, P = 0.022) were independent predictors of poor CSS. The predictive nomograms were developed to predict the OS and CSS with a C-index of 0.837 and 0.760. Good statistical performance on internal validation was shown by calibration plots.

CONCLUSION

In conclusion, this study demonstrated that BMI was an independent prognostic factor for OS and CSS in LARC patients treated with nCRT followed TME. A nomogram incorporating BMI, neural invasion, pre-CA19-9, ypStage, age, and adjuvant chemotherapy could be helpful to predict the OS and CSS.