The Influence of Mixed Histologic Type within a Primary Colorectal Cancer on Lymph Node Metastasis

Hitoshi Katanagi, Toshiaki Yoshioka, Osamu Aizawa, Yuri Saito, Osamu Muto, Kenji Koyama

First Department of Surgery, Akita University School of Medicine

This study, which included 330 cases of advanced colorectal cancer, assessed the effects of mixed histologic types within primary cancer on the lymph node metastatic rate. We investigated the histologic type contained in primary cancer with a high lymph node metastatic rate, and the nodal metastatic rates of each histologic type depending on their volume within primary cancer. Cancer which contained a poorly differentiated histologic type as a minor subpopulation within the primary cancer (73%) had a significantly higher nodal metastatic rate than cancer without mixed histologic types (48%) (p<0.05). When primary cancer contained the poorly differentiated or mucinous histologic type as a minor subpopulation, the nodal metastatic lesion usually contained the histologic type of a major subpopulation and seldom contained the poorly differentiated (23%) or mucinous (16%) histologic type. From these results, it was considered that the condition which promotes the development of the poorly differentiated histologic type within a primary cancer is important in lymph node metastasis in cancer with mixed histologic types.

Key words
colorectal cancer, lymph node metastasis, histomorphological heterogeneity

Reprint requests
Hitoshi Kotanagi First Department of Surgery, Akita University School of Medicine
1-1-1 Hondo, Akita, 010 JAPAN

Accepted
September 13, 1995

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