Contour prognostic model for predicting survival after resection of colorectal liver metastases: development and multicentre validation study using largest diameter and number of metastases with RAS mutation status

BACKGROUND

Most current models for predicting survival after resection of colorectal liver metastasis include largest diameter and number of colorectal liver metastases as dichotomous variables, resulting in underestimation of the extent of risk variation and substantial loss of statistical power. The aim of this study was to develop and validate a new prognostic model for patients undergoing liver resection including largest diameter and number of colorectal liver metastases as continuous variables.

METHODS

A prognostic model was developed using data from patients who underwent liver resection for colorectal liver metastases at MD Anderson Cancer Center and had RAS mutational data. A Cox proportional hazards model analysis was used to develop a model based on largest colorectal liver metastasis diameter and number of metastases as continuous variables. The model results were shown using contour plots, and validated externally in an international multi-institutional cohort.

RESULTS

A total of 810 patients met the inclusion criteria. Largest colorectal liver metastasis diameter (hazard ratio (HR) 1.11, 95 per cent confidence interval 1.06 to 1.16; P < 0.001), number of colorectal liver metastases (HR 1.06, 1.03 to 1.09; P < 0.001), and RAS mutation status (HR 1.76, 1.42 to 2.18; P < 0.001) were significantly associated with overall survival, together with age, primary lymph node metastasis, and prehepatectomy chemotherapy. The model performed well in the external validation cohort, with predicted overall survival values almost lying within 10 per cent of observed values. Wild-type RAS was associated with better overall survival than RAS mutation even when liver resection was performed for larger and/or multiple colorectal liver metastases.

CONCLUSION

The contour prognostic model, based on diameter and number of lesions considered as continuous variables along with RAS mutation, predicts overall survival after resection of colorectal liver metastasis.

Rate of Organ Space Infection Is Reduced with the Use of an Air Leak Test During Major Hepatectomies

BACKGROUND

Organ/space surgical site infections (OSIs) constitute an important postoperative metric. We sought to assess the impact of a previously described air leak test (ALT) on the incidence of OSI following major hepatectomies.

METHODS

A single-institution hepatobiliary database was queried for patients who underwent a major hepatectomy without biliary-enteric anastomosis between January 2009 and June 2015. Demographic, clinicopathologic, and intraoperative data-including application of ALT-were analyzed for associations with postoperative outcomes, including OSI, hospital length of stay (LOS), morbidity and mortality rates, and readmission rates.

RESULTS

Three hundred eighteen patients were identified who met inclusion criteria, of whom 210 had an ALT. ALT and non-ALT patients did not differ in most disease and treatment characteristics, except for higher rates of trisegmentectomy among ALT patients (53 vs. 34 %, p = 0.002). ALT patients experienced lower rates of OSI and 90-day morbidity than non-ALT patients (5.2 vs. 13.0 %, p = 0.015 and 24.8 vs. 40.7 %, p = 0.003, respectively). In turn, OSI was the strongest independent predictor of longer LOS (OR = 4.89; 95 % CI, 2.80-6.97) and higher rates of 30- (OR = 32.0; 95 % CI, 10.9-93.8) and 45-day readmissions (OR = 29.4; 95 % CI, 10.2-84.6).

CONCLUSIONS

The use of an intraoperative ALT significantly reduces the rate of OSI following major hepatectomy and may contribute to lower post-discharge readmission rates.

Performance measures of surgeon-performed colonoscopy in a Veterans Affairs medical center

BACKGROUND

Quality indicators are increasingly emphasized in the performance of colonoscopy. This study aimed to determine the standard of care rendered by surgeon-endoscopists in a Veterans Affairs (VA) medical center by evaluating the indications for colonoscopy and outcome performance measures according to established quality indicators for colonoscopy.

METHODS

A prospective standardized computer endoscopic reporting database (ProVation MD) was retrospectively reviewed. All colonoscopies performed by attending surgeons at the San Diego VA medical center between 1 January 2004 and 31 July 2007 were included in the study. Patients with charts that had incomplete reporting were excluded. The quality indicators used included the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) criteria for colorectal cancer screening, the American Cancer Society (ACS) guidelines for postcancer resection surveillance, and the American Society of Gastrointestinal Endoscopists (ASGE) quality indicators for colonoscopy.

RESULTS

The data for 558 patients (96% men) were analyzed. The average patient age was 63 years (range, 25-93 years). Almost all the colonoscopies (99%) were performed in accordance with established criteria. The most common indications for colonoscopy were screening (n = 143, 26%), non-acute gastrointestinal bleeding (n = 127, 23%), polyp surveillance (n = 100, 18%), postcancer resection surveillance (n = 91, 17%), abdominal pain (n = 19, 4%), and anemia (n = 14, 3%). Postcancer resection surveillance colonoscopies were performed according to recommended criteria in 98% of the cases. The cecal intubation rate was 97%, and the overall adenoma detection rate was 26%. Two patients (<1%) experienced complications requiring intervention.

CONCLUSION

The study data indicate that surgeon-performed colonoscopies meet standard quality criteria for indications and performance measures. The authors therefore conclude that surgeon-endoscopists demonstrate proficiency in the standard of care for colonoscopy examinations.

Lower Body Negative Pressure Treadmill Exercise is More Comfortable and Produces Similar Physiological Responses as Weighted Vest Exercise

Lower body negative pressure (LBNP) treadmill exercise can generate a hypergravity load on the lower body that may improve athlete performance by mechanical and cardiovascular adaptations. This study compared the cardiovascular responses, subjective exertion and discomfort levels produced by LBNP exercise with those generated by a weighted vest (WV). We hypothesized that LBNP exercise is more comfortable than WV exercise at comparable levels of exercise. Nine subjects exercised on a treadmill at nine conditions, at 5.5 mph for 15 minutes, in which they ran in random order to avoid confounding effects: 100 %, 110 %, 120 %, 130 %, and 140 % body weight (BW), the latter four conditions were achieved by either LBNP chamber or WV. Heart rate (HR) and oxygen consumption (.VO(2)) were monitored continuously using ECG and open circuit spirometry. At the end of each test, subjects were asked to give discomfort and exertion scores using a ten-point visual analog scale (10 = maximal discomfort and exertion). For both HR and .VO(2), no significant differences were observed between LBNP and WV. Subjects reported significantly higher discomfort levels when exercising with the WV than with the LBNP at 120 % BW (5.1 +/- 0.55 vs. 3.1 +/- 0.64; p < 0.05), 130 % BW (6.2 +/- 0.42 vs. 2.3 +/- 0.44; p < 0.01) and 140 % BW (6.9 +/- 0.27 vs. 4.7 +/- 0.60; p < 0.01), while maintaining similar exertions at all conditions. Based on these results, LBNP exercise is more comfortable than standard WV exercise, while maintaining similar exertion, HR and .VO(2) values.