Venous thromboembolic disease (VTE) is a multifactorial disease involving the development of blood clots in veins with or without inflammation. It includes two entities: deep venous thrombosis (DVT) and pulmonary embolism (PE). The major underlying factors, hypercoagulability, haemodynamic changes, and endothelial injury, are known as the Virchow triad from the German physician who described them in the 19th century [1]. Many conditions such as surgery, cancer, trauma, and immobilisation can cause one or more of these alterations [2]. Thrombosis associated with cancer, known as Trousseau’s syndrome, was first described by the renowned French physician Armand Trousseau in 1865 [3]. VTE represents a significant cause of morbidity, mortality, and economic burden in cancer patients. The incidence of VTE is increased about six-fold in cancer patients [4]. It is the highest in the case of metastatic disease at diagnosis and fast-growing and biologically aggressive cancers. The incidence is also the highest in the first few months following the diagnosis and may reflect the biology of the tumour or medical interventions such as major surgery and chemotherapy [5]. Other risk factors include advanced age, obesity, comorbidities, primary tumour site, and histologic subtype of cancer [6] [7]. The occurrence of VTE can interrupt essential cancer therapy and cause severe bleeding complications [8]. It also represents the second leading cause of death in cancer patients after the underlying cancer progression [9]. The prothrombotic state caused by cancer is a consequence of tumour and patient-specific factors, including vascular compression, vessel injury, and blood hypercoagulability. The last can result from direct activation of pro-coagulant pathways by cancer cells involving aberrant expression of tissue factor, the release of tumour-derived tissue factor-bearing microparticles, and expression of cell surface proteases that modulate fibrinolytic pathways. Indirect pro-coagulant effects result from the enhanced formation of neutrophil extracellular traps and altered expression of pro-inflammatory cytokines and coagulation factors [8]. There is a scarcity of data regarding cancer and VTE in our country. We, therefore, aimed to describe the epidemiological, clinical, and therapeutic pattern of VTE in cancer patients followed-up in two reference hospitals in Cameroon.

We found that 408 patients followed up for cancer during the study period. Thirty-one of them had a confirmed diagnosis of VTE. The prevalence of 7.6% of VTE among cancer patients was estimated. The mean age was 51 ± 18 years, and the sex ratio was 0.35.

All the patients with VTE had solid cancers, and the most represented primary tumours were located in the uterus (25.7%), the prostate (12.9%) and the lung (9.7%) (Table 1). Carcinoma was the most frequent histologic subtype of cancer, and most of the patients had metastatic disease.

Table 2 shows the type of VTE disease in our study population. Most of the patients with VTE had DVT (74.2%). In three cases, most DVT was proximal and associated with pulmonary embolism (9.7%). Only three (9.7%) patients had bilateral DVT.

In Table 3, we present the factors associated with the occurrence of VTE. Best rest and chemotherapy administered in the month preceding the diagnosis of VTE were the only factors independently associated with the development of VTE in this study population.

*liver, kidney, skin, lymphoma, colon, breast, stomach; **sarcoma, lymphoma, melanoma.

DVT: deep venous thrombosis; PE: pulmonary embolism.

Practically, 80.6% of patients were using compression stockings. Two-thirds of cancer patients were treated with low molecular weight heparin, one-third with anti-vitamin K drugs and only 16.1% with direct oral anticoagulants (Table 4).

*WHO stage 3 or 4. OR: odds-ratio. CI: confidence interval.

LMWH: Low molecular weight heparin; AVK: anti-vitamin K; DOACs: direct oral anticoagulants.

This study aimed to describe the epidemiological, clinical and therapeutic patterns of VTE in cancers patients followed up in two reference hospitals in Cameroon in light of the data available in the literature.

We found a VTE prevalence of 7.6% among all cancer patients. This is close to results previously reported by other research [10] [11] [12]. All those who developed VTE had solid tumours with primary sites being the genitourinary system, the lung, the pancreas and the brain. Previous studies found similar findings [6] [11]. In our research, the genitourinary system came in the first position and was dominated by uterine cancer, specifically cancer of the cervix. The predominance of the female gender may explain this in our sample and the high prevalence of cervical cancer in sub-Saharan Africa [13]. About two-thirds of the patients had a metastatic tumour. The presence of the metastatic disease has been associated with VTE development. In our study, it failed to reach statistical significance after multivariate analysis, but Mulder et al. recently found in a study based on Danish medical registries that the presence of metastasis increased the incidence of VTE in cancer patients [14] significantly. They also reported prior VTE as a risk factor which we found was not associated with VTE. High platelet level was reported as a risk factor by Khorana et al. in 2008 and Simanek et al. one year later, but we did not find a significant association in our study [12] [15]. We found that chemotherapy and low-performance status were the two factors independently associated with VTE development in our sample. For chemotherapy, it is similar to what was previously reported [6] [11] [14]. Although they had a sample different from ours, Guven et al. found that patients with metastatic cancer treated with immunotherapy who had a poor performance status also had an increased risk of thromboembolism [16]. This factor, therefore, need to be taken into account when assessing the thromboembolic risk of cancer patients. Almost all the patients with VTE were prescribed compression stockings, and most of them received low molecular weight heparin (LMWH), sometimes followed by anti-vitamin K drugs (AVK). Only a few of them received direct oral anticoagulants (DOACs). There is only a little evidence concerning the use of DOACs in cancer patients. The AMPLIFY trial published in 2015 concluded that apixaban was a convenient option for cancer patients with VTE [17]. The 2018 guidelines of the International Society on Thrombosis and Haemostasis suggest the use of specific DOACs for cancer patients with an acute diagnosis of VTE, a low risk of bleeding, and no drug-drug interactions with current systemic therapy [18]. Globally the result of this study does not differ too much from what is found in the literature.

The main limitation of this study was its retrospective design. We were unable to get the incidence rate of VTE and determine whether it was highest during the first few months after the cancer diagnosis, as described in many studies.

VTE prevalence is high among cancer patients in Cameroon. It is most frequent in solid tumours originating from the genitourinary system, the lung, the pancreas, and the brain. Development of VTE is independently associated with poor performance status and chemotherapy. Most of the patients were treated with LMWH ± AVK, with a few receiving DOACs.

The authors would like to thank the staff of the Yaoundé General Hospital and the staff of the Douala General Hospital.

Conception and design: Chris Nadège Nganou-Gnindjio, Alain PatrickMenanga.

Data collection: Chris Nadège Nganou-Gnindjio, Huguette Atangana Ekobo, Etienne Atangana Okobalemba, Lade Viche, Félicité Kamdem.

Data analysis and interpretation: Dieudonné Danwe, Huguette Atangana Ekobo.

Manuscript drafting: Chris Nadège Nganou-Gnindjio, Dieudonné Danwe.

Manuscript revision: all the authors.

Approval of the final manuscript: all the authors.

The datasets used for this study are available from the corresponding author on request.

The study was approved by the Institutional Ethical Review Board of the Faculty of Medicine and Biomedical of the University Yaoundé I (Cameroon). Individual informed consent was also obtained from the participants, and all the principles of the declaration of Helsinki were respected.

The authors declare that they have no competing interests.

Nganou-Gnindjio, C.N., Mfeukeu-Kuate, L., Ekobo, H.A., Danwe, D., Okobalemba, E.A., Viche, L., Ndobo-Koé, V., Kamdem, F., Hamadou, B. and Menanga, A.P. (2022) Epidemiological, Clinical and Therapeutic Patterns of Venous Thromboembolic Disease in Cancer Patients Followed up in Two Reference Hospitals in Cameroon. World Journal of Cardiovascular Diseases, 12, 250-257. https://doi.org/10.4236/wjcd.2022.124025