Re: NICE’s recommendations for thromboembolism are not evidence based
The authors of the current NICE guidelines on venous thromboembolism (VTE) have produced a comprehensive and apparently authoritative review of the evidence supporting VTE prophylaxis (1) . While application of many of their recommendations will undoubtedly save lives and reduce VTE-associated morbidity, we remain unconvinced as to the strength of the case to continue VTE prophylaxis for 28 days after colorectal cancer resection.
This represents a fundamental alteration in practice across primary and secondary care for tens of thousands of patients per year in the UK. We suspect that many, possibly the majority of organizations will routinely choose to ignore this advice, and not without justification.
The guideline development group (in which expertise in the surgical management of abdominopelvic malignancy was notable by its absence) proposes this change in practice based principally on three publications that, even when combined, describe the prevention of only 4 episodes of pulmonary embolism in almost 400 patients( 2-4). Even extending the analysis to those patients with proximal deep venous thromboses indicate that only 13 episodes would have been prevented by extending prophylaxis to 28 days, and, since 11 of these were reported in a study in which approximately 50% of patients did not even have malignant disease (4), the relevance of this finding to colorectal cancer (or indeed other abdominopelvic surgery for malignancy) remains unconvincing.
Furthermore, reliance on these three studies, the most recent of which completed recruiting patients almost a decade ago, fails to take into account recent developments such as enhanced recovery protocols and laparoscopic surgery, which have transformed postoperative recovery, reducing the postoperative stress response, immobility and length of stay, all of which would be expected to have a significant bearing on the risk of postoperative VTE.
We anticipate that the uncritical application of these guidelines will put acute NHS trusts and PCT’s (or GP consortia) at loggerheads over precisely who funds extended VTE prophylaxis and will inevitably attract criticism of surgical practice that omits extended prophylaxis, in the event that a patient develops a venous thromboembolism within 28 days of discharge from hospital. Finally, for an elderly cancer population, there is the additional practical difficulty of administration of extended VTE prophylaxis; the guidelines development group acknowledge that post discharge prophylaxis may not be cost effective if more than 37% of patients needed district nurses to administer this therapy.
We believe that there is simply insufficient evidence in these guidelines to justify the major upheaval in clinical practice required to extend VTE prophylaxis to 28 days for the 20,000 patients each year undergoing colorectal cancer resection. Updating guidelines regularly is clearly important, but such substantial changes to clinical practice must be justified on the basis of new and definitive evidence, which is currently lacking.
Gordon Carlson - Professor of Surgery & Consultant Colorectal Surgeon, Salford Royal Hospitals, Salford Royal NHS Foundation Trust
Brendan Moran - Consultant Colorectal Surgeon & Chairman Multidisciplinary Clinical Committee, Association of Coloproctology of Great Britain & Ireland
Nigel Scott - Consultant Colorectal Surgeon & President Association of Coloproctology of Great Britain & Ireland
Graham Williams - Consultant Colorectal Surgeon & President Elect Association of Coloproctology of Great Britain & Ireland
1. Venous thromboembolism: reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients admitted to hospital. http://www.nice.org.uk/nicemedia/live/12695/47920/47920.pdf. NICE 2010
2. Lausen I, Jensen R, Jorgensen LN, Rasmussen MS, Lyng KM, Andersen M et al. Incidence and prevention of deep venous thrombosis occurring late after general surgery: randomised controlled study of prolonged thromboprophylaxis. European Journal of Surgery 1998, 164(9):657-63.
3. Bergqvist D, Agnelli G, Cohen AT, Eldor A, Nilsson PE, Le Moigne-Amrani A et al. Duration of prophylaxis against venous thromboembolism with enoxaparin after surgery for cancer. New England Journal of Medicine 2002, 346(13):975-80.
4. Rasmussen MS, Jorgensen LN, Wille-Jorgensen P, Nielsen JD, Horn A, Mohn AC et al. Prolonged prophylaxis with dalteparin to prevent late thromboembolic complications in patients undergoing major abdominal surgery: a multicenter randomized open-label study. Journal of Thrombosis and Haemostasis : JTH 2006, 4(11):2384-90.
Competing interests: No competing interests