Objective: To investigate whether age or other factors are determinants of distant metastasis in patients with lung cancer.
Study design: Observational study.
Place and duration of study: Department of Nuclear Medicine, Recep Tayyip Erdogan University, Rize, Turkey between December, 2018 and February, 2019.
Methodology: A total of 152 patients with lung cancer, who underwent positron emission tomography/computed tomography (PET/CT) for staging, were included in this study. Patients were grouped according to age (>65 and <65 years) and distant metastasis status. Metastasis localisation of patients was evaluated by PET/CT. Univariate/multivariate regression analyses were performed to determine risk factors for distant metastasis.
Results: No significant difference was found when the relation of distant metastasis with stage distribution was examined in both age groups. Distant metastasis rates were significantly higher in female patients than in male patients (p = 0.019) and in patients with small-cell lung carcinoma (SCLC)-adenocarcinoma than in those with other histopathological subtypes (p <0.001). Most of the patients in both groups had a stage 4 disease, and bone distant metastasis was the most common in both age groups. Univariate/multivariate analyses identified that female gender (p = 0.017/p = 0.003), SCLC subtype (p = 0.013/p = 0.008), T3/T4 tumour (p <0.001/p <0.001), and smoking history of >66 pack-years (p = 0.047/p = 0.047) were independent factors for the presence of distant metastasis.
Conclusion: Although age is not a risk factor for distant metastasis in lung cancer, female gender, T3/4 tumour, SCLC subtype, and smoking history of >66 pack-years are high-risk factors. PET/CT is recommended as the first-choice imaging technique in patients with lung cancer indicated for distant metastasis scanning. Key Word: Lung cancer, PET/CT, Metastases, Histological subtype, T-stage.