Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Science

Program

Surgery

Supervisor

Malthaner, Richard

Abstract

Esophagectomy remains an integral part of cure for patients with esophageal cancer. The operation can be a source of significant morbidity and mortality, which highlights the importance of preoperative risk assessment and careful patient selection. Sarcopenia, defined as loss of muscle and function, and frailty are two measures of decreased physiologic reserve that have been associated with poor outcome in cancer patients. The first objective of this thesis was to summarize the existing literature on the available tools used to quantify frailty and sarcopenia. The second was to perform the first study using the National Surgical Quality Improvement Program (NSQIP) database to investigate the association between the 5-factor modified frailty index (mFI-5) and adverse outcomes in esophagectomy patients. The final objective was to measure sarcopenia and frailty in the same local esophagectomy patient cohort to investigate the association between these metrics of physiologic reserve and severe postoperative complications requiring intensive care. NSQIP data for esophagectomy patients from 2016-2018 were obtained and local patient data was collected from 2010-2016. Frailty was quantified using mFI-5 and sarcopenia status was attained by normalizing skeletal muscle area on preoperative computed tomography scans by sex and height. Based on the NSQIP database, mFI-5 showed associations with post-esophagectomy 30-day morbidity (i.e., Clavien-Dindo grade IV complications) but not mortality. In the local patient cohort, neither sarcopenia nor mFI-5 demonstrated significant associations with postoperative outcomes. In conclusion, sarcopenia and frailty are markers of physiologic vulnerability but may not correspond with statistically and clinically significant outcomes for esophagectomy patients.

Summary for Lay Audience

The definitive surgical treatment for esophageal cancer is an esophagectomy – a complex and physiologically taxing operation in patients already ill patients. The risks of death and severe complications associated with this surgery is high. For this reason, finding a way to understand which patients would do poorly afterwards is important for making decisions about treatment. Sarcopenia is a condition defined by loss of muscle mass and function. Frailty is the overall decline in the body’s ability to respond to stress. Both factors have both been linked to poor outcomes in cancer patients. In our research, we first aimed to summarize the ways sarcopenia and frailty are measured. Second, we investigated whether the 5-factor modified frailty index (mFI-5) – a simple and widely used tool to quantify frailty – was associated with poor outcomes in esophagectomy patients that were captured in the National Surgical Quality Improvement Program (NSQIP) database between 2016-2018. Ours was the first study to apply mFI-5 to these patients. Finally, we took our local population of esophagectomy patients and measured both frailty (using the mFI-5) and sarcopenia (using preoperative computed tomography (CT) scans) to see if either metric was more associated with outcomes severe enough to warrant admission to the intensive care unit (ICU). Based on the NSQIP database study, we found that the mFI-5 was associated with severe complications but not death within 30 days of surgery. In our local cohort, we did not find any meaningful indications that sarcopenia or mFI-5 were associated with admission to the ICU. In conclusion, both sarcopenia and frailty are objective measures of physiologic vulnerability, but these two metrics alone may not be enough to tell us whether a patient undergoing an esophagectomy will have a poor outcome that is clinically meaningful.

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