Surgery (Austin & Northern Health) - Theses

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    The Use of Prehabilitation in Colorectal Cancer Surgery
    Bolshinsky, Vladimir ( 2021)
    Abstract Introduction: Prehabilitation in colorectal cancer surgery is an emerging opportunity in the field of perioperative medicine designed to improve the standard of care. The thesis aim is to identify the current attitudes towards risk stratification and the delivery of prehabilitation programs to colorectal cancer patients. The impact of a “Bundle-of-Care” approach to prehabilitation prior to major GI cancer surgery has not previously been explored. Risk stratification can enable the clinician to differentiate modifiable and non-modifiable risk. Cardiopulmonary exercise testing (CPET) is the gold standard assessment of functional capacity and is therefore the most reproducible risk stratification tool. However, availability of CPET in Australasian Hospitals is limited. Furthermore, the accuracy of traditional CPET parameters is reduced in patients with sarcopenic obesity and chemotoxicity. Conventional CPET focus on VO2 at anaerobic threshold (AT), may be superseded by a holistic approach that analyses multiple physiological and biochemical parameters to not only improve risk prediction, but to optimise reversible patient factors within the prehabilitation window. As part of prehabilitation initiatives, a number of unimodal components have been investigated in isolation. Haematinic prehabilitation to optimize oxygen carrying capacity in circulating blood volume an opportunity for improvement of fitness. Methods: An electronic survey was distributed to all members of the Colorectal Surgical Society of Australia and New Zealand (CSSANZ). A comprehensive review of published trials in preoperative optimisation of GI cancer patients was conducted according to the Preferred Reporting Items or Systematic Review and Meta-Analysis (PRISMA) guidelines. A retrospective cohort of 43 consecutive patients scheduled for major cancer surgery was used to identify if the peakVO2 derived from the patient administered questionnaire, “Duke Activity Severity index (DASI)” would correlate with the CPET peakVO2. A retrospective cohort of 82 consecutive patients was used to investigate novel risk stratification variables. A further retrospective cohort of 65 cancer patients that underwent a ferric carboxymaltose (FCM) infusion prior to surgery were assessed as to the feasibility and potential haematinic optimisation following intervention. Based on the above findings, a protocol was derived for a potential randomized control trial in order to determine if the preoperative functional status (as measured by CPET) of anaemic and/or iron deficient colorectal cancer patients could be improved by preoperative intravenous infusion of FCM. Results: There does not appear to be enough robust data to make specific conclusions based on the systematic review of multimodal prehabilitation in colorectal cancer surgery. There is no harm identified with prehabilitation, however prior to routine integration of multimodal prehabilitation programs into clinical practice, adequately powered trials that utilise CPET, therefore ensuring uniform endpoints would be of benefit. Awareness of objective preoperative risk stratification and prehabilitation amongst CSSANZ members is variable and current utilisation of prehabilitation programs is low. There is growing interest in this area amongst the colorectal community, who regard implementation of prehabilitation programs as technically feasible within the majority of represented institutions. DASI-predicted peakVO2 did overpredict the actual peakVO2 values, with a more significant discrepancy for patients with higher peakVO2. The CPET-derived parameters that were most predictive of reduced overall survival included peakVO2 (corrected to body surface area) and (Ve/VCO2) at anaerobic threshold. Specifically, one in two patients with a preoperative pVO2 <710 ml/kg/m2 and Ve/VCO2 at AT >35 had died within one year of surgery. A preoperative pro-inflammatory state added significant ability to discriminate between survivors and non-survivors. Charlson Co-morbidity Index however, did not discriminate survivors from non-survivors. The overall numbers from the retrospective analysis of FCM infusion did not demonstrate any meaningful conclusions. However, FCM infusion is safe and feasible in this patient population, therefore, the proposed randomized control trial would contribute to the literature on this topic. Conclusion: The “Bundle-of-Care” approach to prehabilitation makes intuitive sense, however robust data is required prior to mass implementation. The survey of CSSANZ members does not demonstrate current use or core knowledge, but there is significant interest. Subjective assessment of functional capacity (such as DASI) is inaccurate and CPET will continue to play an integral role in risk stratification. Specific CPET parameters require further refinement, particularly in sarcopenic patients with significant co-morbidities. Haematinic optimization is safe and would benefit a significant proportion of colorectal cancer patients. A multidisciplinary approach to implementation of prehabilitation programs is key. In order to proceed, it is imperative that early triage of patients to preoperative clinics, identification of reversible comorbid disease, including deconditioning, and implementation of interventions occurs in parallel with the diagnostic work up of the surgical disease.