Tobacco smoking is associated with solid growth pattern in primary lung adenocarcinoma

Several studies have explored whether tobacco consumption is associated with the histologic growth patterns of pulmonary adenocarcinomas, and whether these patterns influence prognosis. However, findings have remained ambiguous. This study aimed at further exploring these associations in a larger cohort, enhancing precision compared to previous studies by assessing growth patterns on digitalized slides.

Resection specimens from 196 patients with pulmonary adenocarcinoma were retrospectively assessed and categorized. Where available, up to three tumour bearing H&E stained slides were digitized. Growth patterns were quantitatively assessed and categorized based on these digital images. Clinical and demographic data, including smoking history, were obtained from patient admission records.

Smoking, particularly heavy smoking (> 30 pack-years), was significantly associated with solid growth, while non- or light smokers were more likely to display an acinar predominance. These two patterns were by far the most prevalent, together accounting for 84.3% of all cases. Median overall survival (OS) for the entire cohort was 47 months. Solid predominant tumours were associated with shorter OS (25 versus 57 months compared to all other predominant patterns, p = 0.042) while lepidic tumours were associated with longer OS (112 versus 46 months compared to all other predominant patterns, p = 0.025). No statistically significant correlation with OS was observed for either acinar, cribriform, or micropapillary tumours.

These findings support an association between smoking behaviour and histologic growth patterns, as well as between growth patterns and OS. The associations appear particularly robust for solid predominant tumour, highlighting their prognostic relevance.