Incidence of venous thromboembolism in patients with colorectal cancer according to oncogenic status.

BACKGROUND: There are conflicting data regarding the role of KRAS mutation on the risk of venous thromboembolism (VTE) in colorectal cancer (CRC) patients. Moreover, the role of other biomarkers such as NRAS or BRAF has not been studied. PURPOSE: To analyze the incidence of VTE in a cohort of patients with CRC based on KRAS, NRAS, and BRAF status. METHODS: We performed a retrospective review of patients with unresectable locally advanced and metastatic CRC (mCRC) and known KRAS/NRAS/BRAF status, attended in the Medical Oncology Department of the Hospital General Universitario Gregorio Marañón (Madrid, Spain). The primary outcome was VTE defined as any venous thromboembolic event that occurred either 6 months before or at any time after the diagnosis of CRC. The biomarker status (KRAS, NRAS, and BRAF) and other predictors of thrombosis were collected. RESULTS: One hundred and ninety-four patients were identified and included in the analysis. Forty-one patients (21.1%) experienced VTE. The incidence was 19.1% in RAS-mutated patients, 28.6% in BRAF-mutated patients and 21% in triple wild-type patients (p = NS). In multivariate analysis, ECOG ≥ 2 was the only independent predictor of VTE (OR 8.73; CI 95% 1.32-57.82; p = 0.025). CONCLUSIONS: In our study, biomarkers have not been associated with an increased risk of VTE in CRC patients. A high incidence of VTE in BRAF-mutated patients has been observed and should be explored in further studies.

Monitoring anti-Xa levels in patients with cancer-associated venous thromboembolism treated with bemiparin.

OBJECTIVE: To analyze the relationship between therapeutic (weight-adjusted) dose of bemiparin and anti-Xa activity in patients with venous thromboembolism (VTE) and cancer in comparison with a cohort of patients with VTE without cancer, and its relationship with outcomes. MATERIALS AND METHODS: This is a prospective cohort study that comprised a cohort of patients with cancer-associated VTE and a cohort of non-cancer patients with VTE, all of them treated with bemiparin. The ethics committee approved the study and informed consent was obtained from the patients. RESULTS: One hundred patients were included (52 with cancer and 48 without cancer), with a median follow-up of 9.8 months. Mean anti-Xa activity was 0.89 (± 0.33) UI/mL in oncological patients and 0.83 (± 0.30) UI/mL in non-cancer patients (mean difference - 0.05 95% CI - 0.18; 0.06). A multiple linear regression model showed that anti-Xa peak was associated with the dose/kg independently of possible confounding variables (presence of cancer, age, sex and eGFR-estimated Glomerular Filtration Rate), in a way that for every 1 UI of dose/kg increase, the anti-Xa peak activity increased 0.006 UI/mL (95% CI 0.003; 0.009) (p < 0.001). The predictive capacity of anti-Xa peak in the oncology cohort showed an area under the ROC curve of 0.46 (95% CI 0.24-0.68), 0.70 (95% CI 0.49-0.91) and 0.74 (95% CI 0.44-0.94) for death, first bleeding and recurrence of VTE, respectively, and none was statistically significant. CONCLUSION: In patients with venous thromboembolism treated with bemiparin, anti-Xa levels were not influenced by the presence of cancer.