Investigation of the diagnostic value of D-dimer examination in cancer patients with suspected pulmonary thromboembolia in the emergency department

Objective: The aim of this study is to examine the diagnostic performance of D-Dimer test in cancer patients who underwent pulmonary computed tomography angiography (CTPA) imaging with the suspicion of pulmonary embolism (PTE) who applied to the Emergency Medicine Department of Ankara University Faculty of Medicine Ibni Sina Research and Practice Hospital. Material and method: In the retrospective study, patients diagnosed with cancer who applied to Ankara University Faculty of Medicine Ibni Sina Hospital Emergency Department between 01.01.2018 and 31.12.2022 and underwent CTPA with the suspicion of PTE were included in the study. The data of the patients to be used in the study were recorded in the study form. Revised Geneva Score, Khorana score, blood gas analysis results (pH, pO2, pCO2, HCO3, lactate), laboratory test results (hemoglobin, white blood cell count, platelet count, and platelet distribution volume), D-Dimer level, and PTE in BTPA presence (PTE present/no PTE) was examined. As the patient outcome; Presence of PTE (presence of PTE/no PTE) in BTPA was examined. Results: Of the patients included in the study, 39.8% were female (n=193) and 60.2% were male (n=292). The mean age of the patients was 68.05±12.085 years. PTE was detected in 30.3% of the patients (n=147). Patients with PTE were 25.9% in the low-probability category, 28.6% in the medium-probability category, and 60.7% in the high-probability category. In our study, in patients with PTE (n=147), the mean D-Dimer level was 5773.44 ±764.43 (95% Confidence Interval: 4262.66-7284.23) ng/mL and the median was 2813 (IQR: 5147) ng/mL, In the low probability group, a threshold value of ≥1950 ng/mL for D-Dimer was found to have a sensitivity of 71.4% and a specificity of 75% in predicting the presence of PTE. The Negative Predictive Value for this threshold value was found to be 88.2%. In the intermediate probability group, a cut-off value of ≥1750 ng/mL for D-Dimer was found to have a sensitivity of 73.2% and a specificity of 58% in predicting the presence of PTE. Threshold values of 500 ng/mL and 1750 ng/mL of D-Dimer were compared for the presence of PTE. PTE (+) probability of D-Dimer level ≥1750 ng/mL in the intermediate probability group (OR=3.763 95%CI: 2.379-5.954) compared to D-Dimer level ≥500 ng/mL (OR=2.125 95%CI: 1.069- 4,220) was found to be higher. Conclusion: In our study, we demonstrated that clinical probability assessment (Revised Geneva Score) provides less clinical benefit in cancer patients than in non-cancer patients, and that diagnostic performance can be improved by using higher cutoff values for D-Dimer testing in cancer patients. Key Words: Cancer, Pulmonary Thromboembolism (PTE), D-Dimer, Emergency Service