In this thesis, I chose to identify and evaluate different monitoring methods on surgeon specific outcomes in colorectal surgery. An initial literature search identified different methods that were applied to a cohort of colorectal patients operated on by general surgeons using an electronic hospital database. Surgeon specific complications were validated with a chart review. General surgeons at The Ottawa Hospital were surveyed on their opinions regarding monitoring outcomes. We can conclude that different methods may be needed as they are dependent heavily on specified target limits. With our derived cohort, we had adequate risk adjustment using a modified Escobar model for 30 day mortality and morbidity. These complications were derived from electronic algorithms and had excellent specificity and sensitivity. General surgeons at The Ottawa Hospital have different opinions regarding monitoring their outcomes and surgeon engagement is necessary to make monitoring fruitful for patients, public, hospital administration, and surgeons.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22039号 / 医博第4524号 / 新制||医||1038(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 濵﨑 洋子, 教授 武藤 学, 教授 妹尾 浩 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22120号 / 医博第4533号 / 新制||医||1039(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 妹尾 浩, 教授 竹内 理, 教授 濵﨑 洋子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22307号 / 医博第4548号 / 新制||医||1040(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 武藤 学, 教授 松田 道行, 教授 髙折 晃史 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22343号 / 医博第4584号 / 新制||医||1042(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 武藤 学, 教授 妹尾 浩, 教授 佐藤 俊哉 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22374号 / 医博第4615号 / 新制||医||1043(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 武藤 学, 教授 松田 道行, 教授 小西 靖彦 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22740号 / 医博第4658号 / 新制||医||1046(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 羽賀 博典, 教授 髙折 晃史, 教授 伊藤 貴浩 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23422号 / 医博第4767号 / 新制||医||1053(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 河本 宏, 教授 濵﨑 洋子, 教授 上野 英樹 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Management of very low rectal cancer is one of the most challenging issues faced by colorectal surgeons. For tumors in the mid and upper rectum, procedures can be done to resect the cancer while maintaining continence, a major determinant of post-operative quality of life. In the low rectum, however, to optimize oncologic outcomes, many surgeons feel compelled to pursue abdominoperineal (APR) over low anterior resection (LAR), a sphincter-preserving procedure. It was hypothesized that after robust adjustment, procedure choice will not be associated with a difference in disease-free survival in the resection of tumors in the low rectum. To analyze this, the US Rectal Cancer Collaborative Database, a comprehensive, multi-center dataset obtained from six institutions between 2010 and 2016, was queried. Patients undergoing TME resection for Stage I-III very low rectal cancers (involvement) were selected for this study. Patients were categorized by procedure- LAR vs APR. Primary outcome was five-year disease-free survival. Secondary outcomes included overall survival, recurrence, length of stay, and complications. An adjusted analysis was performed to account for all known potential confounders. 431 patients with very low rectal cancer treated by either APR or LAR were identified. 154 (35.7%) underwent APR. The overall recurrence rate was 19.6%. Median follow-up time was 42.5 months. An analysis adjusted for age, gender, BMI, ASA class, and pathologic stage observed no difference in disease free survival between operative types (HR=0.90, 95% CI [0.53-1.52], p=0.70). Similarly, secondary outcomes demonstrated no significant difference between operation types, including length of stay (Beta: 0.04, Std. error = 0.25, p = 0.54), overall survival (HR=1.29, 95% CI [0.71-2.32], p=0.39), or complications (OR = 1.53, 95% CI [0.94 - 2.50], p=0.09). In this analysis, no significant difference in disease-free survival or overall survival was observed between patients undergoing APR or LAR for very low rectal cancer. This comprehensive study supports the treatment of very low rectal cancer, less than 5cm from the anorectal ring with no sphincter involvement, by either abdominal perineal or low anterior resection. Further studies may focus on patient-reported and quality of life outcomes which may influence decision-making.

<p>    </p> <p>In the United States, colorectal cancer (CRC) is the third most common cancer and the third leading cause of cancer mortality in men and women. Recent epidemiological evidence has shown that there’s been a steady increase in young onset CRC, underlying a continued need to understand mechanisms that may be contributing to its development. One risk factor that continues to persist and rise is obesity. Obesity is a multifaceted disease characterized by various metabolic and physiologic changes that influence tumorigenesis. Another component that is altered in obesity and has been shown to contribute to CRC is the gut microbiota. Obesity associated gut microbiota is different relative to a lean counterpart and has been linked poor colonic health, which can increase risk for CRC. Researchers have shown that intestinal tumorigenesis is worse in diet induced obesity but given other related conditions like chronic inflammation, the role of the gut microbiota in obesity associated CRC risk has not been adequately isolated. To address this gap and to further explore the role of diet in this relationship given its importance in driving obesity and impacting gut microbiota composition, we performed two studies. First, we assessed the role of obesity and/or two different obesogenic diets on gut microbiota composition and intestinal permeability. We hypothesized that diet and obesity would affect gut microbial community composition and that obese mice would have higher intestinal permeability relative to lean mice regardless of diet. Our results indicated that both diet and obesity were significant predictors and had varying effects on species richness and community structure of the gut microbiota and significantly enriched multiple bacterial taxa. Second, to isolate the role of obesity- and/or diet- influenced gut microbiota on CRC development, fecal microbial transplantation was performed by transferring the intestinal content from mice in the first study into recipient mice before chemical induction of CRC. We hypothesized that the gut microbiota from obese mice on obesogenic diets would promote CRC independent from the development of obesity. Our results indicated that gut microbiota shaped by the obesogenic diets was associated with worse colonic tumor measurements, while the differences in gut microbiota due to obesity or leanness did not affect CRC outcomes. Overall, we have demonstrated that diet and obesity have significant effects on gut microbial communities, but only dietary-induced gut microbial changes promote CRC. These results highlight the importance of understanding dietary effects on gut microbiota in CRC development which improves our ability to determine better strategies of prevention and treatment. </p>