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5 Preoperative Optimization Prior to Exenteration
Marta Climent1 and Miguel Pera2
1 Department of Surgery, Bellvitge University Hospital, Barcelona, Spain
2 Hospital del Mar Universidad Autónoma de Barcelona, Spain
Background
A patient’s general physical condition is the most important determinant of postoperative complications. Pelvic exenteration is a major multivisceral resection with significant morbidity, and therefore patients need to be carefully selected and counseled. Full clinical history, evaluation of comorbidities, and regular medication are paramount for assessing suitability for a pelvic exenteration. Some comorbidities might require further investigations or assessment by other specialists in an attempt to optimize the patient before the surgery. Conditions like pre‐existing neurological symptoms or other functional issues are important, especially as most patients will have one or two stomas [1].
Clinical Examination
Digital rectal examination provides vital information relating to the localization of the tumor, its diameter, and its involvement of the sphincter complex. A bimanual recto‐vaginal and abdominal examination is mandatory to confirm the presence of a central pelvic recurrence, which ideally should be mobile and not fixed to the pelvic sidewall. If necessary, examination under anesthesia, with cystoscopy or colonoscopy often provides useful information [1].
Laboratory Tests
As part of the preoperative assessment, any detected anemia should be corrected [2]. If the patient has diabetes, optimization of glycemic control is essential [3]. In addition, electrolyte or renal impairments should be checked. Nutritional risk assessment should be performed routinely, with full screening including checking plasma albumin [4], prealbumin, total cholesterol, and total protein [5]. C‐reactive protein (CRP) has been shown to be a good independent prognostic marker in patients [6].
Risk Assessment of Morbidity and Mortality
Current approaches to predict postoperative outcomes include scores such as the American Society of Anesthesiologists (ASA) classification and the Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (POSSUM) [7]. Ihemelandu et al. noted that the Eastern Cooperative Oncology Group (ECOG) performance status and Health‐Related Quality of Life (HRQoL) measured by Functional Assessment of Cancer Therapy (FACT‐C) questionnaire are valuable predictors of postoperative morbidity in patients undergoing major surgery [8]. ECOG status has been described as well as a useful tool in the preoperative assessment of patients undergoing pelvic exenteration [9]. Preoperative physical fitness has also been identified as an independent predictor of surgical outcome. For this reason, assessment of functional capacity before a major surgery is paramount. Cardiopulmonary exercise testing (CPET) is probably the most reliable, objective, and precise means of evaluating presurgical physical fitness and the physiologic reserve. This is a dynamic and non‐invasive assessment of the cardiorespiratory system at rest and under stress, integrating expired oxygen and carbon dioxide concentrations with the measurement of ventilatory flow, thus deriving oxygen consumption (VO2) and carbon dioxide production (VCO2) under conditions of varying physiologic stress imposed by a range of defined external workloads. Heart rate, oxygen saturations, blood pressure, and electrocardiogram are monitored simultaneously [10]. The most frequent mode of exercise used is cycle ergometry. CPET is the gold standard method of measuring aerobic capacity, predicting postoperative outcomes, and identifying high‐risk patients [11, 12]. Several studies and systematic reviews have demonstrated that CPET is a useful tool for preoperative risk stratification in patients undergoing cardiac and non‐cardiac surgery. Studies observe that lower VO2 peak and aerobic threshold (AT) indicate patients at increased risk of postoperative morbidity [13]. Alternative tests are six‐minute walk tests, shuttle walking, and stair climbing.
Preoperative Optimization
Identification and correction of modifiable risk factors, like malnourishment or anemia, in the preoperative assessment can improve surgical outcomes. All these factors in addition to poor preoperative physical performance correlate with increased complications and mortality risk after major surgery [2, 3, 12]. Figure 5.1 shows a preoperative algorithm, including some of the risk factors that should be evaluated. Assessment of preoperative functional capacity should be performed with CPET, if available, not only to identify those patients who may benefit from preoperative exercise training but also to prescribe the intensity of the program [14]. To get a good adherence to the exercise program, preferences and needs of patients have to be considered and led by a specialized physiotherapist. Some patients would require supervision in hospital rather than a home‐based program [2, 12]. Neoadjuvant therapies provide the opportunity to train patients before major cancer operations [10]. A recent systematic review supports the role of exercise training in patients undergoing neoadjuvant treatment [15]. Adherence rates were acceptable (66–96%), but the overall impact on HRQoL is still not known.
Anemia Management
Preoperative anemia in patients with cancer is multifactorial, with one‐third of patients having iron deficiency at presentation [3, 16]. The negative impact of preoperative anemia on surgical outcomes is well known. A multivariate analysis of 39 309 patients undergoing major surgery showed that severe anemia was associated with higher in‐hospital mortality (odds ratio (OR) 2.82, 95% confidence interval (CI) 2.06–3.85) and postoperative admission to intensive care (p < 0.001) [17]. A systematic review and meta‐analysis reported increased acute kidney injury and infection in patients with preoperative anemia [18]. On the other hand, allogenic red cell transfusion, which occurs at a higher rate among anemic patients, is also associated with increased mortality and morbidity [3, 18]. Therefore, in order to reduce the risk of postoperative complications, it is necessary to correct anemia before surgery. Oral iron replacement is not always effective in patients with cancer because of the time required for its efficacy and because its action is limited by the inflammation. Therefore the intravenous (IV) treatment option is the most indicated. A single dose of IV ferric carboxymaltose (15 mg/kg body weight) in patients with ferritin < 300 mcg/l, transferrin saturation < 25%, and Hb < 12.0 g/dl for women and Hb < 13.0 g/dl for men has been shown to reduce the need of transfusion during major abdominal surgery in 60% of patients [16].