Angiogenesis at the site of deepest penetration predicts lymph node metastasis of submucosal colorectal cancer

PURPOSE: Intratumor microvessel count has been reported as a useful prognos tic factor in patients with cancer of various organs. This study was undert aken to clarify the relation between microvessel count and lymph node metas tasis in submucosal colorectal cancer. METHODS: Microvessel count was estim ated in 254 invasive tumors that had been resected from patients with submu cosal colorectal cancer. Immunohistochemistry with antibodies against CD34 was performed on archival specimens, and microvessel counts were estimated based on the average count of three fields (original magnification, X400) i n the most vascular area at the site of deepest submucosal penetration. RES ULTS: Microvessel count ranged from 10 to 98, with a median of 40. Lesions with high microvessel counts (greater than or equal to 40) had a significan tly higher incidence of lymph node metastasis than those with low microvess el counts (<40; 21.8 percent vs. 6.2 percent). None of the 79 lesions with low microvessel counts and submucosal invasion up to a depth of 1,500 <mu>m had metastasized to the lymph nodes. In multivariate analysis, microvessel count was an independent risk factor for lymph node metastasis in submucos al colorectal cancer (P = 0.0026). CONCLUSION: Microvessel count at the sit e of deepest submucosal penetration can be one of the most useful predictor s for lymph node metastasis. Analysis that combines microvessel count and d epth of submucosal invasion may predict the occurrence of lesions without l ymph node metastasis.