Tthe impact of cancer on mortality and morbidity in patients with pulmonary embolism: A comparison between cancer and non-cancer patients"

Objective: Venous thromboembolism (VTE) is a high-mortality, high-morbidity, recurrent, and preventable condition. It is well-established that cancer plays a significant role in the predisposition to thrombosis. The aim of this study was to investigate the impact of the coexistence of cancer and embolism on mortality. Materials and Methods: A retrospective review of patient data was conducted through the hospital's electronic medical record system (MIAMED) by screening 12,008 emergency consultations and 2,636 medical oncology clinic consultations referred to the Department of Pulmonology between January 1, 2018, and July 31, 2024. The study population consisted of all patients aged 18 years and older who were diagnosed with pulmonary embolism (PE) and referred to the Department of Pulmonology from the Emergency Department of Akdeniz University Hospital between January 1, 2018, and July 31, 2024. This included both outpatient cases and those admitted to the hospital, as well as patients with PE who were hospitalized under the Medical Oncology/Hematology Clinic and referred to Pulmonology. Patients with PE, both with and without malignancy, were compared based on variables such as age, sex, smoking status, troponin and pro-BNP levels at the time of diagnosis, platelet counts, presence of deep vein thrombosis, comorbidities, length of hospital stay, ICU admission rate, cancer subtype in the cancer patient group, and in-hospital mortality from all causes. Descriptive analyses were performed, with frequency data presented as count (n) and percentage (%), and numerical data expressed as mean ± standard deviation or median (1st-3rd quartile). For comparison of categorical variables, the Chi-square (χ²) test and Fisher's exact test were employed. The normality of numerical data was assessed using the Kolmogorov-Smirnov test. For normally distributed numerical data, the Independent Samples T-test was used, while non-normally distributed data were analyzed using the Mann-Whitney U test. Univariate survival analysis was performed using the log-rank test. In multivariate analysis, independent factors predicting survival were identified using a backward selection method with Cox regression analysis, based on factors identified in previous analyses. Survival rates were calculated using the Kaplan-Meier survival analysis. Clinically significant parameters with similar effects on survival were selected for the model from among the correlated parameters. The model fit and the assumption of proportional hazards were assessed using residual (Schoenfeld and Martingale) analyses. A statistical significance level of p <0.05 was considered for all tests. Results: A total of 14,644 patient records were reviewed during the study period, including 12,008 emergency department patients and 2,636 medical oncology clinic patients referred to the Department of Pulmonology. Among them, 368 patients diagnosed with pulmonary embolism (PE) were selected as the study group. Of these, 67 were followed up on an outpatient basis, while 301 were hospitalized. The mean age of the patients was 63.38 ± 15.55 years. It was found that 18.2% (n=51) of the PE patients were active smokers, with an average smoking history of 38.94 ± 31.91 years. Malignancy was present in 53.5% (n=197) of the PE patients, with the most common types being lung cancer (20.7%, n=76) and colon cancer (5.4%, n=20). Additionally, 42.9% (n=158) of the patients were receiving chemotherapy/radiotherapy. In patients with malignancy, smoking history, frequency of hospital admissions in the last six months, and hospitalization duration due to PE were found to be significantly higher compared to patients without malignancy (p=0.003, p<0.001, p=0.020, respectively). The presence of comorbidities was significantly higher in patients without malignancy compared to those with malignancy (p<0.001). CRP levels were significantly higher in patients with malignancy, whereas platelet counts were significantly lower in this group compared to patients without malignancy (p=0.006, p=0.013, respectively). No significant differences were found between the two groups in terms of leukocyte, troponin, or pro-BNP levels. Infection and in-hospital mortality rates were significantly higher in patients with malignancy compared to those without malignancy (p=0.002, p=0.006, respectively). In our study, the most common histopathological subtype across all cancer groups was adenocarcinoma (27.41%). According to the model designed to evaluate the effects of CRP levels, PE clinical classification, and the presence of infection on survival, the following findings were observed: A 1-unit increase in CRP level was associated with a 1.003-fold reduction in survival (95% CI = 1.000–1.005, p=0.036). Patients with accompanying infection had a 2.973-fold higher risk of reduced survival compared to those without infection (95% CI = 1.293–6.840, p=0.010). Patients with submassive PE had a 4.668-fold higher risk compared to those with non-massive PE (95% CI = 2.258–9.653, p<0.001), and those with massive PE had a 9.997-fold higher risk of reduced survival compared to non-massive PE patients (95% CI = 4.991–20.025, p<0.001). Conclusion: Several risk factors associated with mortality in pulmonary thromboembolism have been previously identified in the literature. In our study, we found that the all-cause mortality rate was higher in PE patients with cancer compared to those without cancer. Therefore, we suggest that the presence of cancer may be one of the factors that increase the mortality risk in pulmonary thromboembolism. Keywords: Pulmonary embolism, cancer, mortalite