Feasibility of predicting hematogenous metastasis in patients with non-small cell lung cancer, taking into account the spread through air spaces

Background. Spread through air spaces (STAS) has long been considered a significant risk factor for local recurrence after segmental lung resection in patients with non-small cell lung cancer (NSCLC). Currently, the study of the biological significance of STAS, including its role in hematogenous metastasis of NSCLC, is relevant. The aim of the study was to investigate the feasibility of predicting hematogenous metastasis in patients with NSCLC taking into account STAS. Surgical specimens from 88 patients with stage IA–IIIA NSCLC (T1–3N0–1M0), who were treated at the department of thoracic oncology of the Cancer Research Institute of Tomsk National Research Medical Center from 2014 to 2019, were evaluated. The patients underwent lobectomy or pulmonectomy with ipsilateral mediastinal lymph node dissection. Of these, 69 patients received adjuvant chemotherapy with carboplatin + paclitaxel. The tissue samples from the primary tumor, surrounding lung tissue, and all removed lymph nodes were examined. Histological and immunohistochemical studies were performed using standard methods. Only cases with adenocarcinoma and squamous cell carcinoma were included in the study. The follow-up period from the time of diagnosis was 5 years. The logistic regression method was used to construct mathematical models. Results. Based on the assessment of clinical and morphological parameters, a mathematical model was developed to predict the feasibility of hematogenous metastasis only in patients with lung adenocarcinoma. Basic tumor parameters, such as TNM stage, differentiation grade, creeping type of structures, proliferative activity, and STAS were assessed. The reliability of the model was χ2=664.730; p<0.001; sensitivity and specificity were 99 % and 88 %, respectively. Without taking STAS into account, the model had a low level of specificity, not exceeding 60 %. It was not possible to construct an effective prognostic model for squamous cell carcinoma. Adjuvant chemotherapy did not affect the results obtained. Conclusion. The study demonstrated a significant role of STAS in predicting the incidence of hematogenous metastasis in patients with lung adenocarcinoma. The study of the role of STAS in hematogenous metastasis is promising for understanding the mechanisms of this form of tumor progression.