Distribution of synchronous and metachronous multiple colorectal cancers.

Rackground/Aims: Synchronous and metachronous multiple colorectal cancers are not rare occurrences. Since features of colorectal cancer depend on tumer location, we focused attention on the tumor distribution of synchronous and meta-chronous lesions in colorectal cancer. Methodology: The records of 1812 patients with colorectal malignancies (either invasive colorectal cancer or high grade dysplasia) were elinicopathologicality analyzed. Results; In one humdred and twenty patients with colorectal malignancies there were aynchronous or metachronous lesions. The distribution of synchronous malignancies showed a signiffcant shift from the proximal to the distal site, while in metachronous malignancies, the distribution of second tumors showed a significant shift from the distal to the proximal site. Conclusions: Our findings suggest, that different types of cancer lesions do exist, hence careful and meticulous examinations are important.