Analysis of clinical and oncological outcomes after simple and intentional lung segmentectomies: the deceptive simplicity of the S6 segment

Background: Currently, few studies analyze postoperative outcomes for different types of segmental resections. Therefore, our aim was to compare lower lobe apex with other simple and intentional segmentectomies, in terms of clinical and oncological outcomes. Methods: A retrospective and multicenter study was conducted on patients who underwent simple and intentional segmentectomies from 2015 to 2020. Inclusion criteria were stage cT1a/b N0 M0 disease, peripheral localization and predicted postoperative forced expiratory volume in one second (ppoFEV1) >60%. Pre, intra and post operative parameters were collected and we performed statistical analysis on overall survival and recurrence. Results: The inclusion criteria were met by 252 patients, with 125 having an anatomical S6 resection ("S6" group) and 127 having another anatomical simple segmentectomy ("others" group). There were no significant differences in baseline data. We noted a worse 5-year disease-free survival (DFS) for the "S6" group (P=0.053). Twenty-eight of 46 patients with relapsed disease had loco-regional recurrence. Of these, 80% belonged to the "S6" group (P<0.001). Conclusions: Oncological outcomes were not the same for all simple and intentional segmentectomies. Particularly, S6 exhibited worse oncological outcomes, mainly in terms of disease-free survival. This disparity could be explained by the unpredictable lymphatic drainage or by the smaller parenchymal volume removed during dissection.