It is estimated that by 2030, cancer treatment will involve 45 million surgical procedures per year worldwide.1 Despite a relatively low incidence of anesthesia-related mortality, perioperative morbidity following major cancer surgery remains a significant contributor to healthcare expenditure.2,3 The aging and increasingly sedentary population in high-income countries including Canada, Australia, and the United States, along with its burgeoning comorbid burden,4 is likely to increase postoperative complication rates and length of hospital stay. The cost of all complications from patients undergoing rectal cancer resections in Australia during 2013 to 2014 totaled $77 million at an average of $28,000 per episode, with over half of patients likely to suffer from complications and be twice as costly. The frequency of complications for patients undergoing intra-abdominal surgery in Canada is also high, at 51.9%, with the occurrence of any complications tripling the cost on average.5,6 The increasing demand on the value-proposition of healthcare has increased interest in prehabilitation and over the past decade has seen a shift in focus by anesthetists to assume the role of perioperative physicians, particularly in the preoperative setting.7

Prehabilitation of the surgical patient refers to the preoperative optimization of functional capacity prior to an anticipated stressor—major cancer surgery—and typically occurs between diagnosis and elective surgical intervention.8 Optimization of patients with malignant disease conveys an extra set of challenges because of the functional decline associated with neoadjuvant therapy9 as well as the time-sensitive nature of the planned surgical intervention. Neoadjuvant chemoradiotherapy per se also offers a window of opportunity, during which time preoperative optimization can occur in anticipation of major surgery.

Randomized-controlled studies have shown that unimodal approaches to prehabilitation can reduce postoperative complications by up to 50%.10,11,12 There has also been emerging research in prehabilitation, for multimodal programs involving exercise, nutrition, smoking cessation, and psychologic support.13,14 Nevertheless, it is unclear if this interest has translated into the clinical domain. This evidence-to-practice gap in healthcare is typically 17 years15; implementation science in the field of perioperative care is only an emerging field. With this survey we have attempted to gain insights into commonly studied implementation outcomes (acceptability, appropriateness, adoption, feasibility, penetration) by surveying attitudes of key stakeholders (surgeons and anesthetists). To date, there has only been one prior survey of North American colorectal surgeons, and none of anesthetists or any other perioperative clinicians.16 Our surveys set out to capture the perspectives and practice patterns among Australasian anesthetists and colorectal surgeons with regards to multimodal prehabilitation programs in major cancer surgery.

Methods

We conducted a survey of fellows of the Australian and New Zealand College of Anaesthetists (ANZCA) and members of the Colorectal Surgical Society of Australia and New Zealand (CSSANZ) to identify the uptake, perspectives, and practice patterns regarding objective risk assessment and prehabilitation in patients scheduled to undergo major cancer surgery.

Permission to survey ANZCA fellows was granted by the ANZCA Clinical Trials Network (CTN), and CSSANZ members by the CSSANZ secretariat following ethics approval from the Peter MacCallum Cancer Centre Ethics Committee, Melbourne, Australia (LNR/16/PMCC/97). An e-mail containing a link to both surveys was distributed via the respective societies in 2016; the ANZCA survey of 17 questions was sent to 1,000 practicing fellows using simple random sampling, as per standard ANZCA CTN policy (as detailed in Appendices 1 and 2), while the CSSANZ survey of 33 questions was sent to all 207 practicing members. We aimed to capture as many ANZCA-affiliated anesthetists as possible (from a total of 5,310). A formal sample size calculation suggested that 131 ANZCA fellows were needed to allow an error margin of 8% for their responses, assuming the target population was 1,000 using a 95% confidence interval-based estimate.

The survey questions were sequentially generated and reduced by a multidisciplinary team led by anesthetists and colorectal surgeons, and included a hematologist, exercise physiologist, physiotherapist, nutritionist, and social worker. Both surveys were divided into several domains investigating the responders’ demographics, practice patterns, and perspectives, with the aim to generate at least two items within these domains using face and content validity. Practice patterns examined preoperative assessment and prehabilitation utilizing exercise, hematinic, and nutrition optimization. Questions examining practices and perspectives were designed as a five-Likert scale, with options such as not available, unsure, or other, and the option to comment where feasible. Excluding demographic questions, a total of 37 questions was reduced to 11 in the ANZCA survey; 31 questions was reduced to 27 in the CSSANZ survey.

The surveys were vetted by the respective societies and then piloted among four anesthetists and three colorectal surgeons respectively in our institution. Adjustments were continuously made based on feedback prior to online distribution. Surveys were administered using SurveyMonkey (Palo Alto, CA, USA). The electronic survey included logic which allowed further questioning based on responses to primary questions.

Duplicate responses were avoided. Allocation was blinded, IP addresses were not logged, and all responses remained anonymous. All participants received an e-mail reminder two weeks following the initial e-mail distribution date. Non-participation was assumed if no response was seen one month following the second e-mail. When measuring the proportion of responses to a survey item, the number of respondents to each survey was used for consistency purposes.

Result

The number of respondents included 155 of 1,000 anesthetists and 71 of 207 colorectal surgeons, with over 50% of each group graduating after the year 2000. On a weekly basis, 70% (50/71) of responding colorectal surgeons performed two to five major colorectal resections, whereas 77% (119/155) of the responding anesthetists cared for less than two patients undergoing major cancer surgery (Table). The surveys showed that the preoperative team is still dominated by the surgeon and anesthetist, with frequent consultation of organ-specific physicians such as cardiologists and respiratory physicians. Non-medical staff, such as dieticians, physiotherapists, and smoking cessation representatives, were either reported as unsure, never, or rarely involved in more than 59% of cases (42/71 and 106/155) (Fig. 1). The American Society of Anesthesiologists physical status classification was the most common tool used for risk stratification by anesthetists and colorectal surgeons (Fig. 2).

Table Characteristics of respondents
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Fig. 1
figure 1

Incidence of preoperative clinician involvement by specialty. This graph shows anesthetists and surgeons reporting that other clinicians, particularly allied health, are infrequently involved in the primary preoperative care of patients undergoing major cancer surgery. A = anesthetist; CS = colorectal surgeon

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Fig. 2
figure 2

Incidence of type of risk assessment scores utilized in clinical practice. This graph shows that the ASA is used most frequently, with most other risk assessments infrequently used. A = anesthetists, ASA = American Society of Anesthesiologists physical status classification; CCI = Charlson Comorbidity Index; CS = colorectal surgeons; ECOG = Eastern Cooperative Oncologic Group score; HAQ = Hospital-specific Health Assessment Questionnaire; NSQIP = American College of Surgeons’ National Surgery Quality Improvement Program; POSSUM = Physiologic and Operative Severity Score for the enumeration of mortality and morbidity

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Preoperative assessment of risk and evaluation of functional capacity (fitness)

Both anesthetists and colorectal surgeons rarely used objective measurements of fitness (Fig. 3). Less than 10% of anesthetists (9/155) and colorectal surgeons (6/71) routinely utilize cardiopulmonary exercise testing (CPET). Nevertheless, 46% (33/71) of colorectal surgeons believe CPET to be useful, and 40% (62/155) of anesthetists believe there is robust evidence for objective functional testing in major cancer surgery. Two-thirds (93/155) of surveyed anesthetists lack access to a CPET laboratory. Reasons for non-use for the remaining 21 respondents included time and logistical problems, requesting, interpreting, or acting upon the results (16/21), or a lack of knowledge of the test itself (3/21).

Fig. 3
figure 3

Incidence of use of objective functional capacity for risk assessment. This graph shows that objective assessments are infrequently used. A = anesthetists; CPET = cardiopulmonary exercise testing; CS = colorectal surgeons; ISWT = incremental shuttle walk test; 6MWT = six-minute walk test

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Preoperative evaluation of hematinic and nutritional status

Anemia is frequently assessed by the preoperative anesthetist (131/155) and colorectal surgeon (70/71); however, while almost all colorectal surgeons screen for iron deficiency, 39% (28/71) would perform the test in the absence of anemia. Conversely, 20% (31/155) of anesthetists never screen for it even in the presence of a hemoglobin of less than 100 g·L−1. When iron deficiency anemia is identified, colorectal surgeons (64/71 vs 36/71) are more likely to treat it with iron infusion than with oral therapy compared with anesthetists (99/155 vs 91/155) (Fig. 4).

Fig. 4
figure 4

Predominance of strategies used for the preoperative treatment of iron deficiency anemia. This graph shows the comparative predominance of each intervention between anesthetists and colorectal surgeons. Colorectal surgeons have a greater preference to treat iron deficiency anemia with intravenous iron infusion. A = anesthetists; CS = colorectal surgeons; EPO = erythropoietin; Intraop = intraoperative; PRBC = packed red blood cells; Preop = preoperativef

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Formal nutrition assessment scores are not utilized by the anesthetist (less than 9/155) or colorectal surgeon (less than 10/71). Subjective assessment or knowledge of the body mass index (BMI) may lead half the surveyed colorectal surgeons to consult a dietician (48/71). Anesthetists (34/155) mostly do not consult dieticians even if malnutrition is found.

Biomarkers to assess for general function and nutrition such as albumin and blood sugar level are used by colorectal surgeons (55/71 and 47/71), but somewhat less by anesthetists (104/155 and 94/155) (Fig. 5).

Fig. 5
figure 5

Incidence of use of biomarkers for preoperative risk assessment. This figure shows that albumin is most frequently used to assess nutrition. BSL is also used frequently. Colorectal surgeons are more likely to also use pre-albumin than anesthetists are. A = anesthetists; BNP = brain natriuretic peptide; BSL = blood sugar level; CRP = C-reactive protein, CS = colorectal surgeons; HbA1c = glycated hemoglobin

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Perspectives regarding prehabilitation

There is uniform agreement between anesthetists (125/155) and colorectal surgeons (64/71) that functional capacity affects postoperative outcomes. Nevertheless, more than two-thirds of both groups have mixed opinions on the strength of evidence for prehabilitation (12/71 and 47/155). Colorectal surgeons feel that they would see benefit from prehabilitation programs (65%, 46/71), while just half of anesthetists believe that both their patients (70/155) and their surgical colleagues (73/155) would expect benefit from such programs.

The current implementation of prehabilitation programs remains low in the practices of colorectal surgeons and anesthetists, with the potential for expansion in their institutions (Fig. 6). In patients not receiving neoadjuvant chemotherapy, 69% (49/71) of colorectal surgeons would be prepared to delay surgery for at least two additional weeks. This figure increases to 79% (56/71) in patients receiving neoadjuvant chemotherapy. Anesthetists do not believe their patients are routinely risk stratified (58/155), though they are unlikely to believe their patients would benefit from a delay in surgery (12/155).

Fig. 6
figure 6

Perceptions regarding utility and deliverability of objective functional assessment and prehabilitation programs. This figure shows that there is widespread belief that physical reserve is correlated with postoperative outcome, but that the practical application of this is impeded by a need for more evidence. A = anesthetist; CS = colorectal surgeons

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Discussion

Prior evidence has shown that reductions in functional capacity are correlated with an increase in postoperative complications.17,18 Our results broadly indicate that while anesthetists are regularly involved in preoperative assessment, structured risk assessment and objective functional assessment of patients scheduled for major cancer surgery remain less frequently used. Moreover, key components of a prehabilitation program, especially nutritional assessment, are poorly understood and integrated into clinical practice.

There is a difference in perception of benefit among the two groups, which may act as a barrier to implementing effective preoperative care. More colorectal surgeons see benefit in prehabilitation; however, anesthetists perceive that fewer surgeons view prehabilitation to be of benefit. This is further reinforced by the fact that a larger proportion of colorectal surgeons responded than anesthetists. Differences in response rates and quality of responses between anesthetists and colorectal surgeons in this regard may be a result of different focus among craft groups, with most responding colorectal surgeons having a greater oncologic focus, whereas anesthetists were surveyed from a general base, with oncologic surgery constituting only part of their practice. The strongest evidence base for objective risk assessment and prehabilitation has been in intracavity surgery,19,20 whereas our definition of major surgery may also include other oncologic surgery, such as head and neck surgery or breast surgery. More evidence is required to determine whether prehabilitation should include these surgical specialties.

Prehabilitation can only be performed in the window period between cancer diagnosis and definitive surgery. The perception of how much time is available differs between groups. The timing of anesthetist preoperative assessment in Australian practice is highly variable and is institution-, surgeon-, and patient-dependent. Time to scheduled date of surgery can range from days to weeks and is affected by the use of neoadjuvant therapy. While more than half of responding anesthetists believed that patients were not adequately risk stratified, far fewer believed that patients would benefit from postponing surgery on occasion. It is unclear why this is the case but may be a result of timing of the assessment. Ultimately, this is a conservative approach compared with the colorectal perspective, where, despite the need for timely surgical intervention for colorectal cancer patients, most of the respondents were prepared to delay elective surgery. This was particularly true for advanced rectal cancer cases where neoadjuvant chemoradiotherapy is firmly integrated into the care pathway. Neoadjuvant therapy, while being a major contributor to a reduction in functional capacity, provides a window in which to risk-stratify, discuss the appropriateness of delaying surgery, and provide prehabilitation. Therefore, a significant potential exists for a period of preoperative assessment and management by an extended multidisciplinary team. Early referral is required to maximize this window period for effective prehabilitation.

The general anesthetist contributes significantly to perioperative care for patients undergoing major cancer surgery, given that three-quarters of the surveyed cohort care for less than two such patients per week. It is likely that this would be reflected, if not further emphasized, among non-respondents. As the care of oncologic major surgery crosses multiple anesthesia subspecialties, most anesthetists are likely to provide the bulk of perioperative care to patients undergoing such surgery at some point in their careers. Further education should therefore be targeted at all anesthetists, rather than just at those with a special interest in oncoanesthesia or geriatric anesthesia.

In current practice, the recognition and integration of any allied health profession in the preoperative setting is rare. Both colorectal surgeons and anesthetists rarely assess and manage malnutrition; while a dietician may be involved in cases where it has been subjectively identified, this does not appear to be routine.

Exercise assessment and prehabilitation

While both groups agree that functional capacity is associated with outcomes, and that it can be reduced with cancer therapy, they are hesitant to believe that current methods of assessment and treatment can improve outcomes.9 The CPET is a dynamic, symptom-limited, non-invasive test that provides objective analysis of the functional integration of the cardiovascular, pulmonary, hematinic, and cellular metabolic systems.21 The CPET has been increasingly used in the perioperative setting over the last decade22 and is considered the gold standard test of functional capacity.23 The utility for CPET has been established preoperatively in patients with non-small-cell lung cancer as a marker for morbidity and mortality24,25,26,27 and has been incorporated into international guidelines.28 Its use for major intra-abdominal surgery has been increasingly studied. While studies have shown that CPET may have a role in risk stratification for esophageal, urological, pancreatic, hepatic, and colorectal cancers, a 2016 systematic review by Moran et al. identified the need for further research in certain areas—particularly in areas of colorectal and upper gastrointestinal surgeries, with a lack of consensus regarding variables and definitions of such outcomes by CPET.19 The recently published METS trial covering major non-cardiac surgery has confirmed the value of peak oxygen uptake measured by CPET in predicting non-cardiac complications after surgery. An important finding of this study was the lack of credibility of subjective assessments of cardiac risk in predicting outcomes.29 Further, other variables such as the minute ventilation to carbon dioxide expiratory ratio, heart rate response, and CPET kinetics during the recovery phase have shown promise but have yet to be examined in a large cohort.19,30,31 In addition, the effect of physiologic reserve on return to intended oncologic therapy has also been examined,32,33 and may be a useful outcome to measure in future studies examining the role of CPET in major cancer surgery.

Our surveys suggest that both craft groups infrequently use objective risk assessments of functional capacity either because of perceived insufficient evidence or a lack of access to resource-intensive tests such as CPET. The Duke Activity Status Index (DASI) has previously shown modest correlation with peak oxygen uptake in patients undergoing intra-abdominal surgery for cancer.34,35 The METS trial showed that the DASI can predict postoperative outcomes in a heterogenous cohort undergoing major surgery.29 Other alternatives to CPET, such as the six-minute walk test, do exist and are infrequently used despite their relative simplicity. This may be in part be due to a lack of evidence in cancer-specific cohorts and lack of high-grade validated studies comparing these tests with the gold standard of CPET or postoperative outcomes.36

Preoperative exercise within a prehabilitation program can rapidly improve functional capacity before surgery, and is well-placed to combat the deconditioning suffered as a result of sedentary lifestyle and neoadjuvant chemotherapy.9,37 While preoperative exercise improves postoperative outcomes in lung cancer patients,38 its role in improving postoperative outcomes in major abdominal cancer surgery has yet to be elucidated. Randomized-controlled trials have shown that preoperative exercise in major abdominal cancer surgery improves functional outcomes, but none have been adequately powered to examine the effect of preoperative exercise on postoperative complications, and none have examined the effect of preoperative exercise on postoperative mortality.20,39

Nutrition assessment and prehabilitation

As reflected in our survey results, nutrition in the preoperative phase is unfamiliar among anesthetists and some colorectal surgeons. The BMI is almost exclusively used by responding anesthetists and colorectal surgeons, along with comparing acute weight loss and actual body weight with ideal body weight, to identify increased nutritional risk. Nevertheless, a 2011 systematic review by Gupta et al. showed that in head and neck, gastrointestinal, thoracic, and gynecologic cancers, BMI has no association with perioperative morbidity and mortality.40 While others have shown evidence in predicting postoperative outcomes, a consensus as to the utility of any particular tool has yet to be formed.41

Nutritional prehabilitation is another emerging field in cancer patients. Promising pilot studies have shown a benefit in preoperative functional capacity after whey supplementation or immunonutrition; but, like other prehabilitation studies, these pilot projects require validation in larger randomized-controlled studies.42,43,44 The importance of nutrition and postoperative outcomes should be reinforced by perioperative specialists, particularly anesthetists, when identifying at-risk patients and proactively involving dietetics.

Hematinic assessment and treatment

Despite being readily accessible on the Australian Pharmaceutical Benefits Scheme, anesthetists appear inclined to treat preoperative iron deficiency anemia with oral rather than intravenous iron infusion. While further adequately powered randomized-controlled trials are needed to show the effect of preoperative iron infusion on postoperative outcomes, and therefore cost-benefit, studies have shown symptomatic improvement within days and a rise in hemoglobin within one to two weeks.45,46 Symptomatic benefit has also translated to patients with non-anemic iron deficiency.47

Risk assessment

The American Society of Anesthesiologists physical status (ASA-PS) score has been regularly used in clinical anesthesia, as well as for research, reimbursement, and resource allocation,48 and this is reflected in our surveys. Studies have shown correlations between the ASA-PS in postoperative outcomes such as infection, anastomotic failure, pulmonary complications, length of stay, and mortality. In a range of surgical cohorts including orthopedic, gastrointestinal, gynecologic, and thoracic,48,50,51,52,53,54,55 the ASA score is simple and can be performed rapidly at the bedside, but it carries significant inter-rater variation and is therefore thought to lack discriminatory power56 compared with more complex but informative risk scores.57

Approaches to preoperative assessment

Anesthetists are more likely to perform a cardiorespiratory assessment whereas colorectal surgeons are likely to examine the patient more globally, as shown by a relative increased focus on anemia and nutrition assessment. Anemia and blood transfusions are related to cancer recurrence, and malnutrition is associated with infection and anastomotic leak, but colorectal surgeons will also consider other functions, including independent stoma management, and quality of life factors such as postoperative incontinence.57,59,60 This reflects two different perspectives towards cancer care, which is likely to be improved with increased multidisciplinary involvement from allied health practitioners.

Future directions

Our surveys suggest that preoperative risk assessment of functional capacity in the preoperative period is relatively rapid and brief. Nevertheless, responding colorectal surgeons have indicated their willingness to delay surgery for an extra two to four weeks, suggesting that access and evidence are the two limiting factors in translating the knowledge into practice. A 2015 joint task force of combined professional anesthesia organizations, consumers, and other stakeholders ranked the impact of prehabilitation with exercise as a top ten research priority in perioperative medicine.61 Despite promising research into prehabilitation programs, the evidence base largely consists of small, single-centre studies, and has yet to examine meaningful outcomes such as morbidity and mortality. Recent research into multimodal programs has examined a variety of combinations of different interventions, including physical fitness, nutrition, hematinic, smoking and alcohol cessation, and psychologic interventions, but an ideal combination of interventions has yet to be determined.14 The overall use of prehabilitation is low and there is not enough evidence for a change in practice to occur. These barriers and opportunities identified may serve as a basis for implementation of science studies in the perioperative literature. Nevertheless, our survey suggests a willingness among stakeholders to participate in the high quality research that will be needed to improve the uptake of prehabilitation into mainstream practice.

Current limitations in undertaking research to build the existing evidence base include a lack of pre-existing infrastructure, a lack of access to objective risk assessment, and poor capacity for preoperative exercise training programs. This is compounded by limited preoperative utilization of physiotherapists, exercise physiologists, and dieticians. A potential space exists for multidisciplinary clinical and research engagement in the two to four-week preoperative period, which will build the evidence base.

Limitations

The major limitation of this study is the low survey response rate, particularly among anesthetists. As such, our data are susceptible to selection bias and are neither adequately powered to detect differences between subgroups or subspecialties nor draw definitive conclusions beyond the general overview in cancer surgery that has been presented here. The response rate may have been so low because non-respondents are not interested in perioperative medicine in cancer surgery—a relatively new field—or more specifically, in prehabilitation. Fellows that graduated after the year 2000 had the highest representation in our respondents, which may support this notion. As this study was performed on Australian and New Zealand organizations, its applicability to transnational cohorts may be limited. Nevertheless, our findings may be of relevance to countries with similar cultures in anesthesia, particularly with similar training procedures, case-mix, and burden of disease, such as Canada.62

Conclusion

Our survey shows that Australian anesthetists and surgeons are willing to participate in high quality prehabilitation research. Currently, allied health expertise is lacking, risk assessment of functional capacity is inconsistently used, and the uptake of prehabilitation is low. Anesthetists in particular have a stronger cardiorespiratory focus, whereas colorectal surgeons are likely to consider hematinic and nutritional status, although iron deficiency is underdiagnosed and undertreated. The involvement of allied health staff in the preoperative period could potentially improve risk assessment, particularly regarding nutrition, and allow for early triage of preoperative and postoperative interventions. Institutions should consider redesigning processes and improving infrastructure to ensure early multidisciplinary referral to improve risk stratification, while allowing research into prehabilitation programs. The significant potential for expansion of prehabilitation programs as high value and low cost interventions is dependent on the effectiveness of these interventions being confirmed by adequately powered, multi-centre randomized-controlled trials in the future.