The impact of predominant histopathological pattern and other histopathological factors on survival in pulmonary adenocarcinomas

Background: Adenocarcinoma is the most common subtype of lung cancer. Histopathologically, lung adenocarcinoma is classified into five distinct patterns: lepidic, acinar, papillary, solid, and micropapillary. In 80-90% of cases, heterogeneous histopathological patterns are observed. This study aimed to evaluate the impact of predominant histological patterns on survival in surgically treated patients, as well as to identify other clinical, demographic, and histopathological factors affecting prognosis. Methods: In this retrospective cohort study, 499 patients who underwent surgery for primary lung adenocarcinoma were evaluated. Survival data were obtained from electronic medical records. Demographic, clinical, and histopathological parameters were analyzed for both surviving and deceased patient groups. Univariate and multivariate Cox regression analyses were conducted to determine independent predictors of mortality. Results: A total of 499 patients who underwent anatomical resection for primary lung adenocarcinoma and had complete medical data were retrospectively analyzed. The mean age was 61±8.1 years, and 77.6% of patients were male. The median tumor size was 3.5 cm (range: 2.30-5.20 cm), and the median Charlson comorbidity index was 3 (range: 2-4). The 5-year overall survival (OS) rate was found to be 64.5%. The 5-year OS was 59.8% in males and 77.7% in females (p=0.001). Regarding the side of surgery, the 5-year OS was 57.8% for left-sided resections and 67.9% for right-sided resections (p=0.024). The presence of a micropapillary pattern and acinar predominance were both identified as negative prognostic factors for survival (p=0.017, p=0.024, respectively). Additionally, lymphatic invasion and postoperative complications were found to be independent prognostic factors adversely affecting survival in multivariate analysis (p=0.014, p=0.011). Conclusion: This study demonstrates that predominant histological patterns significantly influence survival in lung adenocarcinoma. The presence of a micropapillary component and acinar predominance were identified as negative predictive factors in multivariate analysis. We believe that relying solely on the TNM staging system may be insufficient for survival prediction; factors such as predominant histological pattern, lymphatic invasion, gender, Charlson comorbidity index, and postoperative complications should also be taken into account. These criteria may also be considered in planning oncological treatment strategies.