Clinical Significance of Absolute Monocyte Count in Venous Thromboembolism Patients with Lung Cancer

Purpose: To investigate the role of the absolute monocyte count (AMC) as a predictor of response to anticoagulation and survival in lung cancer patients with venous thromboembolism (VTE).

Methods: We retrospectively collected the clinical data of 134 patients with lung cancer who were diagnosed with VTE and treated with anticoagulation between July 2008 and May 2014 in a single institution. Baseline characteristics, laboratory findings, response to anticoagulation, and survival since the diagnosis of VTE were analyzed in low (n = 67) and high (n = 67) AMC groups according to median AMC (640/μL) at the time of VTE diagnosis.

Results: The majority of patients had non-small cell lung cancer (n = 110, 82.1%), stage IV (n = 86, 64.2%), and pulmonary thromboembolism (n = 102, 76.1%) and were incidentally diagnosed with VTE without any sign of thrombosis (n = 103, 76.9%). Patients’ characteristics and laboratory values were not significantly different between low and high AMC groups. Among 90 patients available for evaluation of response to anticoagulation, high AMC group (n = 10/46, 21.7%) was more refractory to anticoagulation than low AMC group (n = 3/44, 6.8%) (p = 0.044). In addition, high AMC group showed worse overall survival than low AMC group (median 9.6 vs. 5.9 months, p = 0.038). In multivariate analysis, high AMC and low albumin were independent poor prognostic factors.

Conclusion: High AMC is associated with refractoriness to anticoagulation and poor prognosis in lung cancer patients with VTE. Further evaluation is warranted to confirm these findings.