Associations of Tumor Proximity to the Intersegmental Plane and Segmental Bronchial Orifice with Insufficient Surgical Margins during Segmentectomy for Non-Small Cell Lung Cancer: A Japanese Single-Center Retrospective Study

Background: Achieving an adequate surgical margin is a key oncological consideration during segmentectomy for early-stage non-small cell lung cancer (NSCLC). This study aimed to determine whether anatomical distance parameters measured on computed tomography (CT) were associated with insufficient surgical margins. Methods: We retrospectively analyzed 151 patients with NSCLC who underwent segmentectomy or subsegmentectomy between 2012 and 2025. Tumor location was quantified on preoperative CT using the distance from the tumor to the intersegmental plane (Distance-ISP) and the bronchus-to-tumor distance (BTD). Factors associated with an insufficient pathological margin (≤10 mm) were evaluated using multivariable logistic regression. Results: The median age was 71 years, and the median pathological tumor size was 20 mm. An insufficient pathological margin (≤10 mm) was observed in 90 of 151 patients (59.6%). In the multivariable analysis, shorter Distance-ISP remained independently associated with an insufficient margin (odds ratio [OR], 1.18 per 5-mm decrease; 95% confidence interval [CI], 1.04-1.34; p=0.009). The association for shorter BTD was in the same direction but was not statistically significant (OR, 1.10 per 5-mm decrease; 95% CI, 0.98-1.24; p=0.118). Conclusion: Shorter Distance-ISP was independently associated with an increased likelihood of an insufficient surgical margin, whereas the independent association with BTD was not confirmed. Assessing both anatomical parameters may provide complementary information for preoperative surgical planning.