|Year : 2015 | Volume
| Issue : 2 | Page : 135-139
Clinicians' awareness on thromboprophylaxis in cancer-associated thrombosis
Hannah E Omunakwe1, Onyeanunam Ngozi Ekeke2, Kaladada I Korubo3
1 Department of Pathology, Braithwaite Memorial Specialist Hospital, Port Harcourt, Nigeria
2 Department of Surgery, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria
3 Department of Haematology, University of Port Harcourt Teaching Hospital, Port Harcourt, Nigeria
|Date of Web Publication||21-Nov-2015|
Hannah E Omunakwe
Haematology Unit, Pathology Department, Braithwaite Memorial Specialist Hospital, Port Harcourt, Rivers State
Source of Support: None, Conflict of Interest: None
Context: Venous thromboembolism is a significant cause of morbidity and mortality in cancer patients. Awareness of patients at risk will enable clinicians proffer thromboprophylaxis promptly and thus reduce morbidity and mortality. Aims: The aim of the study is to evaluate the clinicians' awareness and practice of thromboprophylaxis in cancer patients. Materials and Methods: A descriptive questionnaire-based survey of clinicians in the University of Port Harcourt Teaching Hospital. Statistical analysis used: The Statistical analysis was done using SPSS 17.0. Results: Ninety-four clinicians responded (78.33%). Forty (42.55%) could define Venous thromboembolism (VTE) appropriately. Fifty-seven (60.63%) clinicians saw 1-6 cancer patients monthly and majority; 84 (89.36%) said cancer patients were at higher risk of VTE than noncancer patients. The most commonly cited risk factors for cancer-associated thrombosis (CAT) were the site of the tumor (98.9%), surgery (76%), body mass index (76%). Thirty-seven (39.36%) reported offering some form of thromboprophylaxis to their cancer patients. Low molecular weight heparin was most prescribed; by 24 (64.87%) respondents. Fifty-four (57.45%) of the respondents had no idea of the effect of heparins on tumor progression. Conclusions: The awareness of CAT and the importance of thromboprophylaxis amongst our clinicians is low.
Keywords: Awareness, cancer-associated thrombosis, thromboprophylaxis, venous thromboembolism
|How to cite this article:|
Omunakwe HE, Ekeke ON, Korubo KI. Clinicians' awareness on thromboprophylaxis in cancer-associated thrombosis. Afr J Med Health Sci 2015;14:135-9
|How to cite this URL:|
Omunakwe HE, Ekeke ON, Korubo KI. Clinicians' awareness on thromboprophylaxis in cancer-associated thrombosis. Afr J Med Health Sci [serial online] 2015 [cited 2021 Apr 21];14:135-9. Available from: http://www.ajmhs.org/text.asp?2015/14/2/135/170187
| Introduction|| |
Venous thromboembolism (VTE) is a major cause of morbidity and mortality in hospitalized patients, accounting for 5-10% of in-hospital fatalities.  Pulmonary embolism (PE) has been identified as the most common preventable cause of hospital death.  The relationship between cancer and VTE has been established for many years now  ; cancer patients have a higher risk of developing VTE and even a high risk of mortality following VTE.  The understanding of the pathophysiology of cancer-associated thrombosis (CAT), the contribution of the hemostatic system in the progression of cancer and the role of antineoplastic treatment on activation of the coagulation should raise the suspicion of CAT among clinicians giving care to cancer patients.
The incidence of cancer is increasing in developing countries, and mortality from cancer is said to be worse in developing countries.  Epidemiology data identify thrombosis as the second leading cause of mortality in cancer patients following the disease itself.  It has been estimated that one in seven hospitalized cancer patients who die do so from PE.  A recent report by Kotila et al. from Ibadan showed that cancer patients made up to 12.2% of cases treated, and prostate cancer patients were more affected.  The prospective study by Muleledhu et al. in Uganda of deep venous thrombosis (DVT) following major abdominal surgery for 82 patients showed that 5% had DVT postsurgery and cancer was the most common risk factor.  Despite this, prophylaxis is underused because of the lack of awareness of the problem, failure to recognize the many clinical signs that may be associated with thromboembolism, misconception of the risk levels, lack of awareness of consensus guidelines, insufficient clear clinical evidence covering all patient groups amongst other reasons. 
Prevention of thromboembolism can be one of those measures that can help to improve the quality of life of cancer patients.
There is a paucity of data on VTE in Nigeria, the prevalence and risk factors peculiar to Nigerians have not been clearly delineated. A report of the prevalence of VTE at postmortem done in Ibadan, Nigeria showed a prevalence of 2.9% and malignancy was the commonest predisposing risk factor.  There is no published data about the awareness, attitude and practice of Nigerian doctors toward thromboprophylaxis in cancer patients. This study aims to determine this in this teaching hospital.
| Materials and Methods|| |
The questionnaire was developed and it sought amongst others to gather information on the clinicians experience with cancer care, the clinicians' belief regarding the risk of VTE in cancer, concerns about thromboprophylaxis and what they prescribed, their knowledge and use of risk assessment models available for VTE. The clinicians were requested to put down their email addresses if they wanted more information on CAT.
The study was carried out from June to September 2012; the hospital as at the period of the study had 350 doctors in its employ. A total of 120 questionnaires were distributed among a third of the clinicians in the hospital. The research team visited all the clinical departments in the hospital during their clinical seminar meetings and shared the questionnaires to doctors who were present early enough so as not to disrupt the meeting. The questionnaires were picked up within 10-20 min. The questionnaires were collected and analyzed with descriptive statistics. SPSS Inc. Released 2008. SPSS Statistics for Windows, Version 17.0. Chicago: SPSS Inc. was used.
| Results|| |
A total of 120 questionnaires were distributed to clinicians in the hospital; 94 doctors (78.3%) filled and returned the questionnaires. Of these, 23 (24.5%) were consultants, 29 (30.9%) were senior registrars, 39 (41.5%) were registrars and 3 (3.2%) were house officers. They had an average of 10.84 ± 7.78 years of experience in medical practice (range 1-42 years) and were from different clinical backgrounds (surgeons 31.9%, pediatrics 23.4%, internal medicine 18.1%, family medicine 13.8%, hematology 6.4%, otorhinolaryngology 4.3% and anesthesia 2.1%).
Of the 94 respondents, 17 (18.1%) indicated that Venous thromboembolism was normal hemostasis, 45 (47.9%) identified them as abnormal hemostasis, 15 (16.0%) identified them as thrombosis in the veins and the muscles, 40 (42.6%) identified VTE as thrombosis affecting veins and having an embolus to the lungs, 6 (6.4%) identified VTE as thrombosis affecting the veins only.
Seventy 74 (78.7%) admitted that they had seen patients with VTE in their practice, while 16 (17.0%) said they had not seen any case of VTE and 5 (5.3%) gave no response to that question. Of the 16 respondents who had not seen patients with VTE before, 13 (81.3%) of them were in the early phase of the residency training.
Forty (42.6%) of the respondents had heard of "risk stratification systems" for patients suspected to have VTE, 51 (54.3%) reported that they had not heard of the term. Thirty-three (82.5%) of the respondents that admitted to knowing about risk stratification reported that they had no risk stratification model that they use as the standard in their departments, 5 (21.5%) reported that they did not know if there was one that was used in their department. None of the respondents could give a name of a risk stratification model that was used in their department.
Some of the clinicians that responded reported not seeing cancer patients in their practice 13 (13.8%), 39 (41.5%) saw 1-3 cancer patients a month, 20 (21.3%) saw 4-6 cancer patients, 4 (4.3%) saw 7-10 cancer patients, while 6 (6.4%) saw >10 cancer patients in a month. An overwhelming 84 (89.4%) of the doctors reported that cancer patients were at risk of developing VTE, 5 (5.3%) reported that they were not at risk of VTE while 2 (2.1%) reported that they did not know if there was any risk. Of the 84 respondents that reported that Cancer was a significant risk factor for VTE, 71 (84.5%) reported that cancer patients were at higher risk of VTE than other patients, 3 (3.6%) said they were at equal risk for other patients and 1 (1.2%) reported that cancer patients were at less risk of VTE compared to other patients.
Of the 94 respondents, 80 (85.1%) advised early ambulation, 53 (56.4%) used pressure stockings while 69 (73.4%) of the respondents reported having prescribed pharmacological thromboprophylaxis for prevention of DVT. Thirteen (18.8%) of these respondents reported that they knew the patient would need thromboprophylaxis so they prescribed it, 19 (27.5%) stated that they had treated patients previously who had certain symptoms and later developed VTE, thus for any similar case, they would prescribe thromboprophylaxis. Another 21 (30.4%) prescribed thromboprophylaxis because they had a routine to offer it to certain groups of patients while 33 (44.9%) reported that they risk-stratified patients before prescribing thromboprophylaxis.
37 (39.4%) of the respondents reported that they have used anticoagulants for thromboprophylaxis in cancer patients specifically. Twenty-four (64.9%) used low molecular weight heparins (LMWH), 10 (27.0%) used warfarin, 7 (18.9%) used unfractionated heparin (UFH) and 18 (48.7%) reported using Aspirin as anticoagulant to prevent thrombosis.
On the knowledge of the possibility of the use of heparins to prevent thrombosis as well as early metastasis of cancer, 54 (57.5%) reported that they did not know, 19 (20.2%) said it did not, 1 (1.1%) said it had a role preventing early metastasis, while 20 (21.3%) left the question unanswered.
27 (28.7%) of the respondents were willing to put down their E-mails and basic information on CAT was E-mailed to them.
| Discussion|| |
Deep venous thrombosis refers to the formation of one or more blood clots (thrombus) in the body's large veins, most commonly in the lower limbs.  Venous thromboembolism, refers to the formation of a blood clot within the vein (DVT) which may embolize and be carried to the lungs leading to a life threatening condition-PE. It is a major cause of morbidity and mortality in hospitalized patients. The need to prevent all thrombi requires an educational process to alert the clinicians to the long-term consequences of asymptomatic VTE. Two (2.12%) of the respondents in this survey, expressed that there was no need to prescribe thromboprophylaxis if there was no evidence of VTE. This is an erroneous thinking as the detection of asymptomatic VTE is becoming a clinical problem with CT scans performed for cancer staging  and they have a clinical impact on prognosis of cancer patients, which is similar to symptomatic VTE. 
The questionnaire for this study was distributed amongst all cadres of clinical staff in our hospital; the respondent rate in this study was 78.33%. The early callers at clinical meetings received the questionnaires of this study because they appeared to be the ones who took their departmental activities, practice, and training seriously. From this study, all the consultants from the different specialties reported that they had seen patients with VTE during their practice, 18 (78.27%) of them reported prescribing thromboprophylaxis. In spite of the fact that most of the clinicians have seen patients with VTE, prescribe thromboprophylaxis and some know of risk stratification models; none could recall a name of a model used as the standard in their department. This is a reflection that such protocols may not exist, or if they do, they are not regularly followed .
A clinical model was devised by Well et al., and prospectively validated, with which patients can be classified as having a high, intermediate or low probability of developing DVT based on history and clinical signs.  The American College of Chest Physicians also has the most commonly followed protocol for thromboprophylaxis  ; this protocol has been adopted by some other countries like the Asia-Pacific  and others have adapted theirs similar to this.
There are evidence-based guidelines for risk stratification, prophylaxis and treatment of VTE in cancer patients. The American Society for Clinical Oncology guideline,  the National Comprehensive Cancer Network  and European Society for Medical Oncology  also have risk groups and guidelines for thromboprophylaxis and treatment of cancer-associated thrombosis. Presently, we are not aware of any documented Nigerian national guideline for risk stratifying, diagnosis or treatment of venous thrombosis in any group of patients. Clinicians apply some of the guidelines documented in some of these international society guidelines, by their individual discretion.
The respondents reported seeing an average of 2.87 cancer patients monthly, thus it is important for clinicians to be abreast with these guidelines.
A significant number of the respondents 84 (89.36%), identified cancer as an important risk factor for VTE, however only 37 (39.36%) reported that they had used anticoagulants as thromboprophylaxis in cancer patients, the most common pharmacological agent used was LMWH by 24 (64.87%) of these respondents. Available guidelines have suggested the use of the following pharmacological agents LMWH, UFH, the pentasaccharide fondaparinux for thromboprophylaxis.
There is a significant disparity between knowledge and practice in this study population; this may be because there is no specific guideline for assessment and treatment of VTE in cancer patients in this hospital. However, this finding is similar to other centers in Asia  and Europe.  Some of these studies highlighted that despite the presence of evidence-based guidelines, appropriate thromboprophylaxis was severely underused in all types of at-risk cancer patients and other patient groups. In general, the reason seems to be a lack of knowledge about prevalence and seriousness of DVT, scarcity of hospital or unit-wide policies for prophylaxis and lack of encouragement by seniors.
The knowledge of the anti-tumor effects of LMWH was almost nonexistent in the respondents, as only 1 (1.06%) of the respondents reported knowledge that it had some antitumor effects. 54 respondents (57.45%) reported not knowing about its antitumor effect. LMWHs do not only have an effect of preventing thromboembolic disorder, studies have suggested that anticoagulation with LMWHs may also offer additional benefits through direct antitumor activities such as inhibition of angiogenesis, inhibition of the release of coagulation proteases, immunomodulatory effects and apoptosis  ; these mechanisms help to reduce the progression of the cancer.
This study highlights that despite the presence of internationally acceptable evidence-based guidelines, appropriate thromboprophylaxis is remarkably underused in cancer patients in this center, largely due to low awareness of cancer-associated thrombosis and absence of a hospital-based protocol. A multicenter report by Akinmoladun et al. in Nigeria also showed that about 47.5% of surgeons used prophylaxis routinely in major surgeries and only 27% of them had protocols for the use of thromboprophylaxis in their centers. 
Interestingly, 27 (28.72%) of the respondents in this survey provided an E-mail address through which information on CAT could be sent to them. This shows a very low information-seeking behavior among the study population.
This study is limited in the sense that it was only done in one center and all the doctors in the center were not given opportunity to fill out the questionnaire, it will give a stronger perspective if more centers are invited to fill a similar questionnaire.
| Conclusion|| |
The study showed that many of the doctors had seen patients with venous thrombosis; a good number had prescribed thromboprophylaxis, but only a few risk-stratified their patients before prescribing anticoagulation therapy. We also found that knowledge amongst the clinicians on cancer-associated thrombosis was poor. They prescribed thromboprophylaxis sparingly, and they did not understand the benefits of thromboprophylaxis in cancer patients. This may be due to the absence of a hospital-based or nationally approved protocol for the management of thromboembolic disorders. There is a need for improved awareness and education amongst clinicians on the VTE and adoption or development of a guideline for thromboprophylaxis so as to improve outcome. There is a need to develop programs and hospital-based risk stratification models for cancer patients.
Clinicians and consultants with longer experience in medical practice should show leadership and be involved in creating an enabling environment for the application of internationally accepted or locally developed guidelines for patient management. They should also train younger colleagues on the use of these guidelines to make patient management be of internationally acceptable standard.
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