Retrospective accuracy analysis of Major guidelines and factors for Lymph node metastasis of pT1 Colorectal Cancer

Background The aim is accuracy validation of major guidelines and their adopted unfavorable histologic factors for lymph node metastasis (LNM) in pT1 colorectal cancer (CRC). National Comprehension Cancer Network (NCCN), Japanese Society for Cancer of the Colon and Rectum (JSCCR), European Society for Medical Oncology (ESMO), and French Intergroup Clinical Practice Guidelines (FICPG) are included. Methods Retrospectively, 519 cases receiving oncological resection with lymphadectomy were included. Factors and four pathological parameters: histological differentiation grades (HDG), lymphovascular invasion (LVI), depth of submucosal invasion (DSI)(>1000 μm), and tumor budding (TB) would be analyzed for their impacts on LNM incidence individually and in combination as defined by guidelines. Results HDG, LVI, TB, and gender(female) are risk factors of LNM in multi-variate analysis. All guidelines have significant ability to predict LNM (P<0.001). NCCN and ESMO has similar performance, in terms of sensitivity (63.8%/68.1%), specificity (62.7%/69.5%). JSCCR and FICPG had similar performance, in terms of good sensitivity (100%/100%), and low specificity (25.6%/25.2%). JSCCR/FICPG group has higher sensitivity, lower specificity and accuracy than NCCN/ESMO group. Conclusion HDG, LVI, TB, and gender(female) are independent risk factors of LNM of T1 CRC. DSI is an excellent negative predictor though not an independent risk factor. NCCN/ESMO guideline has the medium sensitivity and requires improvement. JSCCR/FICPG guideline has perfect sensitivity but low specificity, thus exposing to many unnecessary surgeries. There is revision potential of current guideline factors including those beyond current pathological ones to improve LNM prediction accuracy.