Dynamics of D‐dimer in non‐small cell lung cancer patients receiving radical surgery and its association with postoperative venous thromboembolism

BACKGROUND: Venous thromboembolism (VTE) occurs at a high rate after lung cancer surgery and can be attributed to various clinical risk factors. Here, we aimed to determine whether early detection of perioperative D‐dimer and risk‐stratified cutoff values would improve the diagnostic efficacy of VTE. METHODS: In this case‐control study, D‐dimer results were acquired from 171 non‐small cell lung cancer (NSCLC) patients preoperatively and at the first, third, and fifth day after surgery. VTE was confirmed by Doppler ultrasonography and computer tomography pulmonary angiography (CTPA). Repeated measures ANOVA was used to analyze how D‐dimer changed with time and the effects of risk factors on D‐dimer levels. We then compared sensitivity, specificity and negative predictive value, using both adjusted and unadjusted cutoff values. RESULTS: VTE occurred in 23 patients (13.5%) of the study population. D‐dimer levels increased unsustainably after lung cancer surgery (P < 0.001) due to a trough on the third day, and patients who had undergone thoracotomy (P < 0.001) and those at a more advanced tumor stage (P = 0.037) had higher D‐dimer levels. Area under the curve of D‐dimer was greatest on the third day (0.762 [P < 0.001, 95% CI: 0.643–0.882]). Applying stratified cutoff values improved the specificity in the video‐assisted thoracoscopy surgery (VATS) (P = 0.004) and thoracotomy groups (P < 0.001). CONCLUSIONS: D‐dimer levels elevated with fluctuation in NSCLC patients after surgery. Surgical options and tumor stages had an impact on D‐dimer levels. With regard to VTE diagnosis, stratified cutoff values by these two factors showed better accuracy compared with a collective one.. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: The changing pattern of perioperative D‐dimer levels in NSCLC patients who received surgical therapy in a major teaching hospital in Beijing, China was revealed. WHAT THIS STUDY ADDS: Risk‐stratified D‐dimer cutoff values adjusted to surgical methods and disease stages would benefit the exclusion of postoperative venous thromboembolism.