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A Systematic Review of POSSUM and its Related Models as Predictors of Post-operative Mortality and Morbidity in Patients Undergoing Surgery for Colorectal Cancer

  • 2010 SSAT Plenary Presentation
  • Published:
Journal of Gastrointestinal Surgery Aims and scope

Abstract

Introduction

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) model and its Portsmouth (P-POSSUM) and colorectal (CR-POSSUM) modifications are used extensively to predict and audit post-operative mortality and morbidity. This aim of this systematic review was to assess the predictive value of the POSSUM models in colorectal cancer surgery.

Methods

Major electronic databases, including Medline, Embase, Cochrane Library and Pubmed were searched for original studies published between 1991 and 2010. Two independent reviewers assessed each study against inclusion and exclusion criteria. All data was specific to colorectal cancer surgery. Predictive value was assessed by calculating observed to expected (O/E) ratios.

Results

Nineteen studies were included in final review. The mortality analysis included ten studies (4,799 patients) on POSSUM, 17 studies (6,576 patients) on P-POSSUM and 14 studies (5,230 patients) on CR-POSSUM. Weighted O/E ratios for mortality were 0.31 (CI 0.31–0.32) for POSSUM, 0.90 (CI 0.88–0.92) for P-POSSUM and 0.64 (CI 0.63–0.65) for CR-POSSUM. The morbidity analysis included four studies (768 patients) on POSSUM with a weighted O/E ratio of 0.96 (CI 0.94–0.98).

Conclusions

P-POSSUM was the most accurate model for predicting post-operative mortality after colorectal cancer surgery. The original POSSUM model was accurate in predicting post-operative complications.

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References

  1. Cancerstats. Available at: www.cancerresearchuk.org. Accessed March 2010.

  2. Sagar PM, Hartley MN, Mancey-Jones B, Sedman PC, May J, Macfie J. Comparative audit of colorectal resection with the POSSUM scoring system. Br J Surg. 1994 Oct;81(10):1492–4.

    Article  CAS  PubMed  Google Scholar 

  3. Knaus WA, Draper EA, Wagner DP, Zimmerman JE. APACHE II: a severity of disease classification system. Crit Care Med. 1985 Oct;13(10):818–29.

    Article  CAS  PubMed  Google Scholar 

  4. Dripps RD, Lamont A, Eckenhoff JE. The role of anesthesia in surgical mortality. JAMA. 1961 Oct 21;178:261–6.

    CAS  PubMed  Google Scholar 

  5. Tekkis PP, Poloniecki JD, Thompson MR, Stamatakis JD. Operative mortality in colorectal cancer: prospective national study. BMJ. 2003 Nov 22;327(7425):1196–201.

    Article  PubMed  Google Scholar 

  6. Jones HJ, de Cossart L. Risk scoring in surgical patients. Br J Surg. 1999 Feb;86(2):149–57.

    Article  CAS  PubMed  Google Scholar 

  7. Copeland GP, Jones D, Walters M. POSSUM: a scoring system for surgical audit. Br J Surg. 1991 Mar;78(3):355–60.

    Article  CAS  PubMed  Google Scholar 

  8. Copeland GP, Sagar P, Brennan J, Roberts G, Ward J, Cornford P, Millar A, Harris C. Risk-adjusted analysis of surgeon performance: a 1-year study. Br J Surg. 1995 Mar;82(3):408–11.

    Article  CAS  PubMed  Google Scholar 

  9. Sagar PM, Hartley MN, MacFie J, Taylor BA, Copeland GP. Comparison of individual surgeon’s performance. Risk-adjusted analysis with POSSUM scoring system. Dis Colon Rectum. 1996 Jun;39(6):654–8.

    Article  CAS  PubMed  Google Scholar 

  10. Whiteley MS, Prytherch DR, Higgins B, Weaver PC, Prout WG. An evaluation of the POSSUM surgical scoring system. Br J Surg. 1996 Jun;83(6):812–5.

    Article  CAS  PubMed  Google Scholar 

  11. Prytherch DR, Whiteley MS, Higgins B, Weaver PC, Prout WG, Powell SJ. POSSUM and Portsmouth POSSUM for predicting mortality. Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity. Br J Surg. 1998 Sep;85(9):1217–20.

    Article  CAS  PubMed  Google Scholar 

  12. Prytherch DR, Ridler BM, Beard JD, Earnshaw JJ; Audit and Research Committee, The Vascular Surgical Society of Great Britian and Ireland. A model for national outcome audit in vascular surgery. Eur J Vasc Endovasc Surg. 2001 Jun;21(6):477–83.

    Article  CAS  PubMed  Google Scholar 

  13. Prytherch DR, Sutton GL, Boyle JR. Portsmouth POSSUM models for abdominal aortic aneurysm surgery. Br J Surg. 2001 Jul;88(7):958–63.

    Article  CAS  PubMed  Google Scholar 

  14. Tekkis PP, McCulloch P, Poloniecki JD, Prytherch DR, Kessaris N, Steger AC. Risk-adjusted prediction of operative mortality in oesophagogastric surgery with O-POSSUM. Br J Surg. 2004 Mar;91(3):288–95.

    Article  CAS  PubMed  Google Scholar 

  15. Tekkis PP, Prytherch DR, Kocher HM, Senapati A, Poloniecki JD, Stamatakis JD, Windsor AC. Development of a dedicated risk-adjustment scoring system for colorectal surgery (colorectal POSSUM). Br J Surg. 2004 Sep;91(9):1174–82.

    Article  CAS  PubMed  Google Scholar 

  16. Wakabayashi H, Sano T, Yachida S, Okano K, Izuishi K, Suzuki Y. Validation of risk assessment scoring systems for an audit of elective surgery for gastrointestinal cancer in elderly patients: an audit. Int J Surg. 2007 Oct;5(5):323–7.

    Article  PubMed  Google Scholar 

  17. Anwar MA, D'Souza F, Coulter R, Memon B, Khan IM, Memon MA. Outcome of acutely perforated colorectal cancers: experience of a single district general hospital.Surg Oncol. 2006 Aug;15(2):91–6.

    Article  PubMed  Google Scholar 

  18. 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. Br J Surg. 2003 Dec;90(12):1593–8.

    Article  CAS  PubMed  Google Scholar 

  19. Brooks MJ, Sutton R, Sarin S. Comparison of Surgical Risk Score, POSSUM and P-POSSUM in higher-risk surgical patients. Br J Surg. 2005 Oct;92(10):1288–92.

    Article  CAS  PubMed  Google Scholar 

  20. Ertan T, Yoldas O, Kilic YA, Kilic M, Göcmen E, Koc M, Tez M. External validation of prognostic models among cancer patients undergoing emergency colorectal surgery. Am J Surg. 2008 Apr;195(4):439–41.

    Article  PubMed  Google Scholar 

  21. Ishizuka M, Nagata H, Takagi K, Horie T, Kubota K. POSSUM is an optimal system for predicting mortality due to colorectal perforation. Hepatogastroenterology. 2008 Mar-Apr;55(82–83):430–3.

    PubMed  Google Scholar 

  22. Jones DR, Copeland GP, de Cossart L. Comparison of POSSUM with APACHE II for prediction of outcome from a surgical high-dependency unit. Br J Surg. 1992 Dec;79(12):1293–6.

    Article  CAS  PubMed  Google Scholar 

  23. Kumar P, Rodrigues GS. Comparison of POSSUM and P-POSSUM for risk-adjusted audit of patients undergoing emergency laparotomy. Ulus Travma Acil Cerrahi Derg. 2009 Jan;15(1):19–22.

    PubMed  Google Scholar 

  24. Law WL, Lam CM, Lee YM. Evaluation of outcome of laparoscopic colorectal resection with POSSUM, Portsmouth POSSUM and colorectal POSSUM. Br J Surg. 2006 Jan;93(1):94–9.

    Article  CAS  PubMed  Google Scholar 

  25. Metcalfe MS, Norwood MG, Miller AS, Hemingway D. Unreasonable expectations in emergency colorectal cancer surgery. Colorectal Dis. 2005 May;7(3):275–8.

    Article  CAS  PubMed  Google Scholar 

  26. Nicole O, Thomas M et al. Evaluation of the P − POSSUM mortality prediction algorithm in Australian surgical intensive care unit patients. ANZ J Surgery.2002;72(10):735–38

    Article  Google Scholar 

  27. Ramkumar T, Ng V, Fowler L, Farouk R. A comparison of POSSUM, P-POSSUM and colorectal POSSUM for the prediction of postoperative mortality in patients undergoing colorectal resection. Dis Colon Rectum. 2006 Mar;49(3):330–5.

    Article  PubMed  Google Scholar 

  28. Senagore AJ, Delaney CP, Duepree HJ, Brady KM, Fazio VW. Evaluation of POSSUM and P-POSSUM scoring systems in assessing outcome after laparoscopic colectomy. Br J Surg. 2003 Oct;90(10):1280–4.

    Article  CAS  PubMed  Google Scholar 

  29. Yii MK, Ng KJ. Risk-adjusted surgical audit with the POSSUM scoring system in a developing country. Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity. Br J Surg. 2002 Jan;89(1):110–3.

    Article  CAS  PubMed  Google Scholar 

  30. Tekkis PP, Kessaris N, Kocher HM, Poloniecki JD, Lyttle J, Windsor AC. Evaluation of POSSUM and P-POSSUM scoring systems in patients undergoing colorectal surgery. Br J Surg. 2003 Mar;90(3):340–5.

    Article  CAS  PubMed  Google Scholar 

  31. Tekkis PP, Kocher HM, Bentley AJ, Cullen PT, South LM, Trotter GA, Ellul JP. Operative mortality rates among surgeons: comparison of POSSUM and p-POSSUM scoring systems in gastrointestinal surgery. Dis Colon Rectum. 2000 Nov;43(11):1528–32.

    Article  CAS  PubMed  Google Scholar 

  32. Neary WD, Heather BP, Earnshaw JJ. The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM). Br J Surg. 2003 Feb;90(2):157–65.

    Article  CAS  PubMed  Google Scholar 

  33. Copeland GP. The POSSUM system of surgical audit. Arch Surg. 2002 Jan;137(1):15–9.

    Article  PubMed  Google Scholar 

  34. Colorectal Cancer Collaborative Group. Surgery for colorectal cancer in elderly patients: a systematic review. Lancet. 2000 Sep 16;356(9234):968–74.

    Article  Google Scholar 

  35. Al-Homoud S, Purkayastha S, Aziz O, Smith JJ, Thompson MD, Darzi AW, Stamatakis JD, Tekkis PP. Evaluating operative risk in colorectal cancer surgery: ASA and POSSUM-based predictive models. Surg Oncol. 2004 Aug-Nov;13(2–3):83–92.

    Article  PubMed  Google Scholar 

  36. Makoto W, Naokuni Y, Tomokazu K et al. Estimation of mortality and morbidity risk in colorectal surgery using POSSUM predictor equation. Japanese Journal of Gastroenterological surgery. 2004; 37 (11) 1714–1720

    Google Scholar 

  37. Vather R, Zargar-Shoshtari K, Adegbola S, Hill AG. Comparison of the possum, P-POSSUM and Cr-POSSUM scoring systems as predictors of postoperative mortality in patients undergoing major colorectal surgery. ANZ J Surg. 2006 Sep;76(9):812–6.

    Article  PubMed  Google Scholar 

  38. Horzic M, Kopljar M, Cupurdija K, Bielen DV, Vergles D, Lackovic Z. Comparison of P-POSSUM and Cr-POSSUM scores in patients undergoing colorectal cancer resection. Arch Surg. 2007 Nov;142(11):1043–8.

    Article  PubMed  Google Scholar 

  39. Poon JT, Chan B, Law WL. Evaluation of P-POSSUM in surgery for obstructing colorectal cancer and correlation of the predicted mortality with different surgical options. Dis Colon Rectum. 2005 Mar;48(3):493–8.

    Article  PubMed  Google Scholar 

  40. Menon KV, Farouk R. An analysis of the accuracy of P-POSSUM scoring for mortality risk assessment after surgery for colorectal cancer. Colorectal Dis. 2002 May;4(3):197–200.

    Article  PubMed  Google Scholar 

  41. Isbister WH, Al-Sanea N. POSSUM: a re-evaluation in patients undergoing surgery for rectal cancer. The Physiological and Operative Severity Score for Enumeration of Mortality and Morbidity. ANZ J Surg. 2002 Jun;72(6):421–5.

    Article  PubMed  Google Scholar 

  42. Valenti V, Hernandez-Lizoain JL, Baixauli J, Pastor C, Martinez-Regueira F, Beunza JJ, Aristu JJ, Alvarez Cienfuegos J. Analysis of POSSUM score and postoperative morbidity in patients with rectal cancer undergoing surgery. Langenbecks Arch Surg. 2009 Jan;394(1):55–63.

    Article  CAS  PubMed  Google Scholar 

  43. Ugolini G, Rosati G, Montroni I, Zanotti S, Alessio M, Giampaolo L, Blume JF, Taffurelli M. Can elderly patients with colorectal cancer tolerate planned surgical treatment? A practical approach to a common dilemma. Colorectal Dis.2008(11):750–755

    Article  Google Scholar 

  44. Ytting H, Christensen IJ, Jensenius JC, Thiel S, Nielsen HJ. Preoperative mannan-binding lectin pathway and prognosis in colorectal cancer. Cancer Immunol Immunother. 2005 Mar;54(3):265–72.

    Article  CAS  PubMed  Google Scholar 

  45. Kørner H, Nielsen HJ, Søreide JA, Nedrebø BS, Søreide K, Knapp JC. Diagnostic accuracy of C-reactive protein for intraabdominal infections after colorectal resections. J Gastrointest Surg. 2009 Sep;13(9):1599–606.

    Article  PubMed  Google Scholar 

  46. Le Gall JR, Lemeshow S, Saulnier F. A new Simplified Acute Physiology Score(SAPS II) based on a European/North American multicenter study. JAMA. 1993 Dec 22–29;270(24):2957–63.

    Article  PubMed  Google Scholar 

  47. Senagore AJ, Warmuth AJ, Delaney CP, Tekkis PP, Fazio VW. POSSUM, P-POSSUM, and CR-POSSUM: implementation issues in a United States health care system for prediction of outcome for colon cancer resection. Dis Colon Rectum. 2004 Sep;47(9):1435–41.

    PubMed  Google Scholar 

  48. Slim K, Panis Y, Alves A, Kwiatkowski F, Mathieu P, Mantion G; Association Française de Chirurgie. Predicting postoperative mortality in patients undergoing colorectal surgery. World J Surg. 2006 Jan;30(1):100–6.

    Article  PubMed  Google Scholar 

  49. Tez M, Yoldaş O, Gocmen E, Külah B, Koc M. Evaluation of P-POSSUM and CR-POSSUM scores in patients with colorectal cancer undergoing resection. World J Surg. 2006 Dec;30(12):2266–9.

    Article  PubMed  Google Scholar 

  50. Bromage SJ, Cunliffe WJ. Validation of the CR-POSSUM risk-adjusted scoring system for major colorectal cancer surgery in a single center. Dis Colon Rectum. 2007 Feb;50(2):192–6.

    Article  PubMed  Google Scholar 

  51. Oomen JL, Cuesta MA, Engel AF. Comparison of outcome of POSSUM, p-POSSUM, and cr-POSSUM scoring after elective resection of the sigmoid colon for carcinoma or complicated diverticular disease. Scand J Gastroenterol. 2007 Jul;42(7):841–7.

    Article  PubMed  Google Scholar 

  52. Ferjani AM, Griffin D, Stallard N, Wong LS. A newly devised scoring system for prediction of mortality in patients with colorectal cancer: a prospective study. Lancet Oncol. 2007 Apr;8(4):317–22.

    Article  PubMed  Google Scholar 

  53. Can MF, Yagci G, Tufan T, Ozturk E, Zeybek N, Cetiner S. Can SAPS II predict operative mortality more accurately than POSSUM and P-POSSUM in patients with colorectal carcinoma undergoing resection? World J Surg. 2008 Apr;32(4):589–95.

    Article  PubMed  Google Scholar 

  54. Ren L, Upadhyay AM, Wang L, Li L, Lu J, Fu W. Mortality rate prediction by Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM), Portsmouth POSSUM and Colorectal POSSUM and the developmentof new scoring systems in Chinese colorectal cancer patients. Am J Surg. 2009 Jul;198(1):31–8.

    Article  PubMed  Google Scholar 

  55. Tan KY, Kawamura Y, Mizokami K, Sasaki J, Tsujinaka S, Maeda T, Konishi F. Colorectal surgery in octogenarian patients—outcomes and predictors of morbidity. Int J Colorectal Dis. 2009 Feb;24(2):185–9.

    Article  CAS  PubMed  Google Scholar 

  56. Ugolini G, Rosati G, Montroni I, Zanotti S, Manaresi A, Giampaolo L,Taffurelli M, Pricolo V. An easy-to-use solution for clinical audit in colorectal cancer surgery. Surgery. 2009 Jan;145(1):86–92.

    Article  PubMed  Google Scholar 

  57. Leung E, Ferjani AM, Stellard N, Wong LS. Predicting post-operative mortality in patients undergoing colorectal surgery using P-POSSUM and CR-POSSUM scores: a prospective study. Int J Colorectal Dis. 2009 Dec;24(12):1459–64.

    Article  PubMed  Google Scholar 

  58. Hariharan S, Chen D, Ramkissoon A, Taklalsingh N, Bodkyn C, Cupidore R, Ramdin A, Ramsaroop A, Sinanan V, Teelucksingh S, Verma S. Perioperative outcome of colorectal cancer and validation of CR-POSSUM in a Caribbean country. Int J Surg.2009 Dec;7(6):534–8.

    Article  PubMed  Google Scholar 

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Authors and Affiliations

  1. University Department of Surgery, Faculty of Medicine-University of Glasgow, Royal Infirmary, Glasgow, G4 0SF, UK

    Colin Hewitt Richards, Fiona E. Leitch, Paul G. Horgan & Donald C. McMillan

Authors
  1. Colin Hewitt Richards
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  2. Fiona E. Leitch
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  3. Paul G. Horgan
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Correspondence to Colin Hewitt Richards.

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Discussion

Discussant

Dr. Matthew M. Hutter (Boston, MA): Thank you, Dr. Richards. Congratulations on an excellent presentation of a very interesting study.

Judging by the multiple studies you examined with conflicting results comparing these three scoring systems, POSSUM, P-POSSUM, and colorectal POSSUM, it seems Logical to proceed with the meta-analysis or systematic review to make order out of the chaos. However, my underlying concern is that the reason the individual studies disagree is that none of the scoring systems are ultimately very good in assessing the quality of care.

For the P-POSSUM, the supposed winner of the three, there’s a wide range in the O/E ratios from .2 to 2.4. That means that there’s either a tremendous range in the quality of care provided to the patients in these studies or that even the P-POSSUM actually does a very bad job of predicting mortality. The problem is we don’t know which one is true.

So my first question then is given what you have learned about these scores, would you want your performance as a surgeon, or that of your authors, your partners, your hospital, hospital system, to be measured or graded According to such scores?

My second question is, if so or if not, what would you do, what important characteristics would you use to create a system that would be better?

Closing Discussant

Dr. Colin Richards: I think you’re right and that, ultimately, no scoring system is perfect. Although the POSSUM models are far from perfect I believe they have some good points.

Number one, the majority of data required is routinely collected, so it’s possible, even retrospectively, to calculate an accurate P-POSSUM score for patients. Secondly, although there is variation in the reported OE ratios I believe that in large populations with rigorous data collection P-POSSUM will prove accurate.

The fact that there is a wide variation in reported OE ratios was one of the reasons we undertook the review. Some studies are reporting an OE ratio of 0.2 while some studies are saying over 2.0.

Having undertaken the review I think some of this variation is certainly because the number of events or the number of deaths in these studies is low. The actual mortality, especially in elective colorectal cancer surgery, is so low that you need a population of at least 400 or 500 patients over an appropriate time period before you can get any sense of it. In smaller populations one or two deaths in a row make a big difference and change the O/E ratio significantly. So I think many of the original studies were underpowered and that’s one of the reasons we are getting such a disparity.

I also believe that is one of the advantages to pooling the data like this; when you take the patient numbers up to 6,000 or 7,000, you get less disparity and the model appears more accurate.

In terms of whether we would be prepared to use it in our hospital, I think the short answer is yes. I think if you’re going to compare mortality between institutions or between surgeons, you’re much better doing it in a risk-adjusted rather than a crude fashion. In terms of risk-adjustment scoring for colorectal cancer surgery, this is the best we currently have.

If we were to create a better system, what would change? I think, ideally, you would want a system which relies on a smaller number of variables, is simple to construct and one which can grade patients pre-operatively instead of having to go back and add things such as pathology results post-operatively. Having a predicted risk of death before you undertake the operation would be advantageous in surgical planning and patient counseling. I would also place more emphasis on whether the surgery was elective or emergency side because that appears to have a greater impact on mortality than say the ‘complexity’ of the operation. Currently in the colorectal POSSUM score, for example.

A complex major operation, such as a high anterior resection adds a significant amount of points, compared to a left hemicolectomy. I think that nowadays, most surgeons would not expect or indeed observe a post-operative mortality difference between such similar elective operations.

Joint contribution: Colin H. Richards and Fiona E. Leitch

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Richards, C.H., Leitch, F.E., Horgan, P.G. et al. A Systematic Review of POSSUM and its Related Models as Predictors of Post-operative Mortality and Morbidity in Patients Undergoing Surgery for Colorectal Cancer. J Gastrointest Surg 14, 1511–1520 (2010). https://doi.org/10.1007/s11605-010-1333-5

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