Rapid Responses to:
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Rapid Responses: Rapid Responses published:
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Preoperative prediction of mortality following colorectal cancer surgery
- Mark J. Cheetham (23 November 2003)
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Re: Preoperative prediction of mortality following colorectal cancer surgery
- Guy F Nash (24 November 2003)
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Deprivation scores and operative mortality
- Paul Glen, Mhairi Simpson, Laura Donnelly, Stephen Leonard, and Angus Macdonald (4 December 2003)
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The application of the ACPGBI Model in comparative audit and informed consent
- George A Khoury (14 December 2003)
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The ACPGBI colorectal cancer model – implications and usage in surgical practice
- Jeffrey D Stamatakis, Paris P Tekkis, Jan D Poloniecki and Michael R Thompson (23 December 2003)
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Are any primary colorectal cancers irresectable?
- Richard G Fiddian-Green (23 December 2003)
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Critical care provision and operative mortality in colorecectal cancer
- Keith S Chapple, M Shanmuganathan, C Viswanathan, AMM Basheer (14 January 2004)
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Mark J. Cheetham, Specialist Registrar in General Surgery QEII Hospital Howlands Welwyn Garden City Herts AL7 4HQ
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Tekkis et al. (1) report the development of a model to predict operative mortality following surgery for colorectal cancer based on a dataset 7374 patients, the data having been collected post-operatively from a number of centres throughout the United Kingdom. The authors suggest that this model can be used in the “preoperative counselling of patients and their carers”. However of the five variables used in the model, only three (age, ASA score and urgency of surgery) can be reliably assessed prior to surgery. Of the remaining two variables, one will only be known with certainty at the conclusion of the operation (resection or no resection) and the Dukes’ staging may not be available for some days after surgery. Although preoperative imaging studies may help in assessing the likelihood of resectability and the presence of distant metastases, this data was not used in the development of the model. These flaws suggest that, while the model may useful in comparative audit between centres or individual surgeons, it is unlikely to be helpful for counselling patients prior to surgery. 1. Tekkis PP, Poloniecki JD, Thompson MR, Stamatakis JD. Operative mortality in colorectal cancer: prospective national study, BMJ 2003;327:1196-1201. Competing interests: None declared |
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Guy F Nash, SpR Colorectal Surgery Chelsea & Westminster Hospital, London SW10 9HN
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One should congratulate Mr. Tekkis et al [1] for their operative risk predictor for colorectal cancer (CRC), although its use in allowing informed consent is limited by its retrospective nature. A truly predictive scoring system may allow a balanced decision whether surgery is indeed beneficial to some patients, as one of the greatest surgical skills is deciding who not to operate on. The data not included in the study from the 499 patients with CRC who avoided surgery may have made a suitable control group to investigate the comparative risk of operating versus not operating. In addition, it was interesting to note that in those patients least fit (ASA IV & V) there was little survival difference whether the CRC was resected or not. This point perhaps highlights the role of stenting in those unfit patients presenting with obstructing CRC. Although not divulged in the study, if indeed there were patients stented (either prior to or in place of surgery) a subset analysis may further our knowledge of the benefit of stenting in such a poor risk group. 1.Tekkis PP, Poloniecki JD, Thompson MR, Stamatakis JD. Operative mortality in colorectal cancer: prospective national study, BMJ 2003;327:1196-1201. Competing interests: None declared |
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Paul Glen, SpR General Surgery Monklands District General Hospital, Lanarkshire, ML6 0JS, Mhairi Simpson, Laura Donnelly, Stephen Leonard, and Angus Macdonald
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The authors are to be congratulated on producing a simple model that will allow comparisons of operative mortality. It is noted however, that the authors do not include deprivation catagory in their scoring system. We provide a colorectal service in a district general hospital setting where 84% of the patients have a deprivation catagory of 4 or more (Morris R, Carstairs V. Which deprivation? A comparison of selected deprivation indices. J Public Health Med 1991;13:318–26), and we were concerned that the model suggested by Tekkis et al (Paris P Tekkis, Jan D Poloniecki, Michael R Thompson, and Jeffrey D Stamatakis Operative mortality in colorectal cancer: prospective national study BMJ 2003; 327: 1196-1201)would not translate to our patient population. The predicted mortality did not specifically take into account socio-economic status and no mention of this was made in the work done to produce this model. However, when we applied the predicted mortality score to our patients, whose data was collected prospectively over the last 5 years, we demonstrated that the model appears to hold fast in a deprived population (Table below). Cancer stage and ASA seem to provide sufficient information on deprivation. Table n= 170 Predicted 30 day mortality all cases= 6.0% Actual 30 day mortality all cases= 6.5% Competing interests: None declared |
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George A Khoury, Consultant Surgeon Conquest Hospital, East Sussex NHS Trust, St Leonard's-on-Sea, TN37 7RD
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Editor The authors conclude (1) that post-operative death can be predicted with a numerical table derived from the statistical model of the ACPGBI and consent to surgery can be truly informed. The model was derived from dataset of 73 selected centres (7,374 patients) over a 12month period, representing 25% of all new rectal cancer diagnoses in the UK. Only 4,491 patients (60%) had complete data for the 5 risk factors. In 30% of 7,374 patients, ASA grade was missing, a significant flaw since it is used twice in the multivariate analysis, both independently and its interaction with cancer resection. Using imputation techniques for missing values of such scale occurring twice is suspect in excluding bias. Although operative mortality for 2,216 patients with missing ASA data is similar to the remaining 5,158 patients, the adjusted odds ratio for each separate group may alter significantly if data were complete. It is questionable that the model assists in consenting patients since half the variables in predicting patient mortality, are only known after surgery. Further, all variables are patient related but the surgeon is probably the most important single factor influencing anastomotic integrity (5-30%) and mortality (2). Patients are not just concerned with 30 day mortality, but with safe discharge from hospital. What matters in patients’ perception, is “hospital and surgeon effect” which prevail. Cormorbidity and cancer extent are important but so is the judgement of the surgeon in careful patient selection avoiding inappropriate surgery and ensuring good life quality, few complications, low recurrence and long-term survival (3). Individual regression lines for each surgeon and centre in hierarchical 3 level regression models, are desirable to include patient (level 1), surgeon (level 2), and hospital (level 3) risk factors. The model is destined to evolve further as surgeons’ patient numbers increase sufficiently to be meaningful. The ACPGBI model is preferable to the P-POSSUM equation (4) as data is easily verified and provided ASA data is complete, it is invaluable for comparative audit. Distinction is necessary between its application for comparative audit as opposed to informed consent. The former excludes the surgeon (the variable under investigation), whilst the latter should include the surgeon as a significant independent variable in mortality for individual patients. The recently reported (5) four times higher mortality for a cohort of patients undergoing major surgery in the UK compared with those in the USA for a given level of risk, would suggest that the “hospital and surgeon effect” are paramount. References (1) Tekkis PP, Poloniecki JD, Thompson MR, Stamatakis JD. Operative mortality in colorectal cancer:prospective national study. BMJ 2003;327: 1196-9 (2) Fielding LP, Stewart-Brown S, Blesovsky L, Kearney G. Anastomotic integrity after operations for large-bowel cancer: a multicentre study. BMJ 1980;281:411-4 (3) Fielding L P, Stewart-Brown S, Dudley HAF. Surgeon-related variables and the clinical trial. Lancet 1978;2:778-81 (4) Khoury G A. Both components of POSSUM ratio require critical analysis. BMJ 2003;326:1397 (5) Bennett-Guerrero E, Hyam JA, Shaefi S, Prytherch DR, Sutton GL, Weaver PC, Mythen MG, Grocott MP, Parides MK. Comparison of P- POSSUM risk adjusted mortality rates after surgery between patients in the USA and the UK. Brit J Surg 2003;90:1593-8 Competing interests: None declared |
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Jeffrey D Stamatakis, Chair National Bowel Cancer Project, Consultant Surgeon Princess of Wales Hospital, Bridgend, Wales, CF31 1RQ, Paris P Tekkis, Jan D Poloniecki and Michael R Thompson
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We would like to thank Mr Glen (e-BMJ 4th December 2003) for his valuable comments on the potential contribution of social deprivation in the ACPGBI colorectal cancer risk model1. We are interested to read the results from the Monklands Hospital where a combination of cancer stage and ASA appeared to act as markers for deprivation. This is an interesting topic which requires further investigation and we aim to evaluate the role of social deprivation on short-term outcomes from the current year’s data of more than 10,000 cases. Mr Cheetham (e-BMJ 23rd November 2003) and Mr Khoury (e-BMJ 14th December 2003) have rightly questioned the use of the ACPGBI risk model in the process of informed consent, as they believe that only three risk factors can be identified preoperatively. We must draw attention to the fact that, in addition to the three factors, patient’s age, ASA grade and mode of surgery, the presence of metastatic disease (i.e. Dukes’ D) should be routinely determined as part of pre-treatment staging, using ultrasound or CT scanning for both elective and emergency cases. (Please refer to the ACPGBI guidelines on the management of colorectal cancer[1]). Dukes’ D is the discriminating stage in the model as this has the main effect on 30- day postoperative survival. Dukes’ stages A – C, where cancer is confined to the bowel and lymph glands, has little effect on early postoperative survival and therefore any effect in the predictive model is minimal. Having four out of the five factors available, the surgeon and patient can then utilise the fifth factor (cancer excision) to balance the risk of major surgery against palliative treatment. On those occasions when the decision to resect cannot be made before the patient is anaesthetised, the possibility of non-resection and related risk can be included in consent. In general, patients with minimal co-morbidity have a survival advantage if the cancer is removed, whereas higher- risk patients may have a better outcome if the cancer is by-passed or stented, as suggested by Mr Nash (e- BMJ 14th November 2003). Mr Khoury draws attention to the level of completeness of ASA recording in the study. We have previously carried out a sensitivity analysis of patients in this study with and without missing ASA values and found no effect on the precision of the model estimates. This is an advantage of population studies utilizing large sample sizes. We anticipate that data completion will improve, as more cases are entered into the model and clinicians find practical benefit in the routine use of such data. The use of ASA, both as an independent risk factor and as an interaction with cancer excision, proved to be critical to the model. The three levels used in the published hierarchical model were the patient, the unit and the region. We specifically studied the unit at level 2, rather than the individual surgeon, to take account of current concepts of multidisciplinary team care and allow for unit variables such as critical care bed provision, nursing numbers, anaesthetic services etc. We agree with Mr Khoury that, for the individual patient, their surgeon’s personal mortality rate is important, but suggest that this should be known by the surgeon and their MDT, as an issue of clinical governance within that Unit, rather than the subject of National Audit. However we also recognise the need for patients and healthcare providers to have specific information on risk and post-operative outcomes. May we draw attention to an online site, www.riskprediction.org.uk, which includes a number of models for risk-adjusting surgical mortality, including that described in the recent BMJ[2] publication. The models are all automated, so that having entered the fields; the clinician can obtain immediate information on the level of risk. This can be used in the clinical situation for direct patient care and for audit purposes. 1. Guidelines for the management of Colorectal Cancer (2001). The Association of Coloproctology of Great Britain and Ireland. 2. Tekkis PP, Poloniecki JD, Thompson MR, Stamatakis JD Operative mortality in colorectal cancer: prospective national study. BMJ. 2003; 327(7425):1196-201. Competing interests: None declared |
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Richard G Fiddian-Green, None None
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The following statement, made by the consultant surgeon who is "Chair National Bowel Cancer Project", alarms me. "Whereas", the statement reads, "higher- risk patients may have a better outcome if the cancer is by-passed or stented" (1). I can just see the registrars using this statement to justify bypassing resectable cancers and gastroenterologists using it to justify stenting. Poor patients. I cannot recall ever having seen a primary colorectal cancer that was not resectable and in most cases suitable for anastomotic reconstruction. On occasions, however, tumour deposits may be left behind and postoperative radiotherapy and adjuvant therapy may be advisable. I have resected more than one case that had been deemed irrectable by other surgeons after exploration and a trial dissection or bypass. I have, however, seen recurrences which I considered to be irresectable or unsuited for surgery because of the advanced stage of the disease. My experience in large bowel cancer might not be as large as the authors of this rapid response but I was once told by someone who had seen the figures that I had for a time the largest surgical practice in a major university tertiary referral center in the US where I had restricted my surgical practice to gastrointestinal diseases. I cannot recall co-morbidities ever having been grounds for not operating on a patient with a resectable colo-rectal cancer. It is, however, possible that chronic lung diseases might be far more prevalent in the old coal mining communities in Wales and other industrial parts of the UK than in the communities in which I have worked. [The community in which I worked in the US was largely supported by the motor industry]. I have, however, repeatedly stressed the fact that the risk of surgery is determined by the presence or absence of incomplete resuscitation before, during or after surgery. In those who are permitted to have an operation in this state the risk of surgery in those with co-morbidities is indeed higher (2,3). The appallingly bad results reported in this paper (4) cannot be used to justify bypassing and stenting. They should be used to justify improving the standard of care for this common surgical disease. The outcomes are even worse in the subgroup treated electively but admitted through the A&E. Unless they are able to provide objective evidence of incomplete resusctation, defined as an abnormally low gastric intramucosal pH, before surgery to support their conservative recommendations the influential authors of this rapid response should retract their statement. Failure to do so could deprive many more patients of definitive treatment without risk of death or a permanent colostomy. 1. Jeffrey D Stamatakis, Paris P Tekkis, Jan D Poloniecki and Michael R Thompson The ACPGBI colorectal cancer model – implications and usage in surgical practice (Rapid response on 23 December 2003) 2. Fiddian-Green RG. Gut mucosal ischemia during cardiac surgery. Semin Thorac Cardiovasc Surg. 1990 Oct;2(4):389-99. 3. Poeze M, Takala J, Greve JW, Ramsay G. Pre-operative tonometry is predictive for mortality and morbidity in high-risk surgical patients. Intensive Care Med. 2000 Sep;26(9):1272-81 4. Paris P Tekkis, Jan D Poloniecki, Michael R Thompson, and Jeffrey D Stamatakis Operative mortality in colorectal cancer: prospective national study BMJ 2003; 327: 1196-1201 Competing interests: None declared |
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Keith S Chapple, Specialist Registrar in General Surgery Pontefract General Infirmary, Mid-Yorkshire Hospitals NHS Trust, West Yorkshire, WF8 1PL, M Shanmuganathan, C Viswanathan, AMM Basheer
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Tekkis et al. describe a model for prediction of operative mortality following surgery for colorectal cancer (1). We were interested to note that access to intensive care (ITU) facilities was not one of the analysed risk factors. The Association of Coloproctology of Great Britain and Ireland (ACPGBI) recommends that access to ITU facilities is necessary in hospitals undertaking colorectal cancer resections (2), although there is no evidence base to underlie this recommendation. Admission to an intensive care unit is associated with substantial morbidity and mortality (3). In the light of service reorganisation throughout the NHS there will be many hospitals that may not have access to ‘on-site’ ITU facilities (4). Thus elucidation of whether admission to an ITU facility is an independent risk factor predicting increased mortality following colorectal cancer surgery may have a significant impact on the working practices of many NHS trusts (and individual surgeons). In our own NHS trust (consisting of three hospitals on separate sites), service reconfiguration has resulted in the loss of ITU facilities from one hospital. A high dependency unit has been maintained in this hospital. Transfer of patients (either pre- or post-operatively) to a different hospital within the trust is thus necessary for any patient requiring ITU support. Elective surgery for patients with colorectal cancer has continued despite this and has allowed investigation into the effect of availability of ITU facilities on operative (thirty-day) mortality following colorectal cancer resection. Interestingly, there was no difference between the operative mortality in the six month period immediately prior to loss of ITU facilities (3/29 patients [10.3%]; p- POSSUM predicted mortality 4.2%) compared to that in the same time period following the loss of ITU facilities (1/26 patients [3.8%]; p-POSSUM predicted mortality 3.9%); P=0.36, Mann-Whitney U test). There was no difference between the two cohorts with respect to age (P=0.77), p-POSSUM physiological score (P=0.22), ASA grade (P=0.53) or Dukes’ stage (P=0.69; all Mann-Whitney U test). Lack of ‘on-site’ ITU facilities required the transfer of a single patient post-operatively, and none pre-operatively. These data suggest that elective colorectal cancer surgery can be performed in units without ‘on-site’ ITU facilities with an acceptable operative mortality rate. 1. Tekkis PP, Poloniecki JD, Thompson MR, Stamatakis JD. Operative mortality in colorectal cancer: prospective national study. BMJ 2003;327:1196-1201. 2. The Association of Coloproctology of Great Britain and Ireland. Guidelines for the management of colorectal cancer. London: The Association of Coloproctology of Great Britain and Ireland, 2001. 3. Vincent JL. Nosocomial infections in adult intensive-care units. Lancet 2003;361(9374):2068-77. 4. Expert group on critical care services, NHS Executive. Comprehensive critical care. A review of adult critical care services. London: Department of Health, 2000. Competing interests: None declared |
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