Prognostic Value of Venous Invasion Detected by Elastin Stain May Surpass Lymph Node Status in Colon Cancer

BACKGROUND: Venous invasion is a poor prognostic factor in colon cancer but is often underreported with significant variability. OBJECTIVES: We aimed to determine the impact of an elastin stain on venous invasion detection in colon cancer and evaluate the value of venous invasion in predicting disease recurrence in combination with lymph node status and other prognostic factors. DESIGN: This is a retrospective analysis of a prospectively collected database. SETTING: This study was conducted at a tertiary cancer center. PATIENTS: A total of 418 patients who underwent curative resection for stage I to III colon cancer and routinely adopted an elastin stain were evaluated. MAIN OUTCOME MEASURES: Venous invasion detection rate after adopting elastin stain, prognostic factors influencing disease recurrences by multivariate Cox regression models, and survival were measured. The zones of lymph node metastasis were defined as LNZ1, LNZ2, and LNZ3, corresponding to metastases in the pericolic, intermediate, and apical nodes. RESULTS: Venous invasion detection rate increased from 11.3% to 35.4% compared with the previous period in which only hematoxylin and eosin stain was performed. Cox regression analysis showed venous invasion (HR, 3.856; 95% CI, 1.249-11.910; p = 0.019) and lymph node metastases (HR, 3.156; 95% CI, 1.094-9.108; p = 0.034) in all stages and LNZ 2, 3 (HR, 2.649; 95% CI, 1.244-5.640; p = 0.012) in stage III to be significantly associated with poor disease-free survival. When stratifying all patients by these 3 factors, patients with stage III [LNZ1/venous invasion (-)] had disease-free survival comparable with stage I, but significantly better disease-free survival than those with stage II [venous invasion (+)] (p = 0.018). Patients with stage II [venous invasion (+)] had better disease-free survival by using adjuvant chemotherapy (p < 0.001). LIMITATIONS: This study was limited by its retrospective design. CONCLUSION: Elastin stain contributed to a considerable increase in venous invasion detection. Venous invasion can be a powerful predictor of poor disease-free survival beyond lymph node metastases when limited to the pericolic area and is useful for deciding the use of adjuvant chemotherapy in stage II colon cancer. See Video Abstract at http://links.lww.com/DCR/B573.