Comparison of Prognosis of Solid and Part-Solid Node-Negative Adenocarcinoma With the Same Invasive Component Size

Our study compared the prognosis of solid node-negative adenocarcinoma sized less than 20 mm with that of part-solid node-negative adenocarcinoma with an invasive tumor size of less than 20 mm.

From 2003 to 2012, 191 patients were selected with a diagnosis of solid or part-solid pathologic node-negative adenocarcinoma with an invasive component sized less than 20 mm. The enrolled patients were categorized into two groups: group 1 had solid adenocarcinoma consisting only of the invasive component, and group 2 had part-solid adenocarcinoma consisting of both an in situ and an invasive component. Recurrence-free survival and overall survival at 5 years were compared using Kaplan- Meier survival analysis and the log-rank test.

The mean size of the invasive component was 15.9 mm in group 1 (n = 92) and 15.2 mm in group 2 (n = 99; p = 0.06), and the mean total lesion size was 15.9 mm in group 1 and 21.0 mm in group 2 (p < 0.001). The median follow-up duration was 54.2 months. The 5-year overall survival rates were 90.3% in group 1 and 93.8% in group 2 (p = 0.160), and the recurrence-free survival rates were 84.0% in group 1 and 93.7% in group 2 (p = 0.037). Lymphovascular invasion and high maximum standardized uptake values were significantly more common in group 1.

Although the total size of the part-solid adenocarcinoma lesions was larger than that of the solid adenocarcinoma lesions, the prognosis of part-solid adenocarcinoma was better than that of solid adenocarcinoma in cases of node-negative adenocarcinoma with invasive components sized less than 20 mm.