Development and Validation of a Predictive Score for Preoperative Detection of Lymphovascular Invasion in Rectal Cancer

ABSTRACT Background Lymphovascular invasion (LVI) is an important prognosticator in rectal cancer (RC). We aimed to determine predictors for LVI in RC and incorporate them into a predictive risk score (PRS). Methods Case‐control analysis of predictors of LVI in RC using data from a national database (2010–2019). Main outcome was LVI in RC and its predictors. Odds ratios of significant independent predictors of LVI were incorporated into a PRS. Results 55,178 patients were included (60.9% male; mean age: 61.3 years). LVI was detected in 10,446 (18.9%). Independent predictors were carcinomas that were signet‐ring cell (OR: 1.98, p < 0.001), moderately differentiated (OR: 1.58, p < 0.001), poorly differentiated (OR: 3.9, p < 0.001), or undifferentiated carcinomas (OR: 4.1, p < 0.001), cN1 (OR: 1.21, p < 0.001), and cN2 (OR: 1.49, p < 0.001), stage and incorporated into a PRS (0–8). Incidence of LVI was 16.3% in the low‐risk group, 27.8% in the intermediate‐risk group, and 40.5% in the high‐risk group ( p < 0.001). The PPV of the score was 40.5%, NPV was 83.7%, accuracy was 82.4%, and specificity was 97.9%. Conclusions High‐grade adenocarcinomas, signet‐ring cell carcinomas, and lymph node involvement in clinical assessment were independently associated with LVI in RC. Incorporation of these predictors into a PRS conferred high specificity and good accuracy.