2017 Volume 59 Issue 11 Pages 2592-2600
The Ⅰp＋Ⅱc type early colorectal cancer has a stalk and is accompanied by a depressed-type tumor in the head, but is different from the Ⅰp type lesion showing polypoid growth. We report clinicopathological features of Ⅰp＋Ⅱc type early colorectal cancer and its natural history. In this study, 22 cases (15 males, 7 females ; average age : 61.1 years old) of Ⅰp＋Ⅱc type early colorectal cancer, and two other Ⅰp＋Ⅱc type early colorectal cancer cases that were followed up, were examined. We performed clinicopathological comparison among the 22 Ⅰp＋Ⅱc type early colorectal cancers, 417 Ⅰp type early colorectal cancers and 147 depressed-type submucosal invasive (SM) colorectal cancers in this study, and examined the characteristics of these lesions. The tumor diameter of Ⅰp＋Ⅱc type early cancers was clearly smaller than that of the 417 Ⅰp type lesions (mean, 12.7mm vs. 16.3mm). The proportion of Ⅰp＋Ⅱc type early cancers that were located at the sigmoid colon [86.4％ (19/22 cases)] was significantly higher than those of Ⅰp type (64.7％) and depressed-type lesions (27.8％). The degree of cancer invasion of Ⅰp＋Ⅱc type early cancers was revealed as T1s [2(9.1％)], T1a [3(13.6％)], and T1b [17(77.3％)]. Lymph node metastases were identified in three (15％, 3/20) of the Ⅰp＋Ⅱc type SM cancers. These rates were significantly higher than the rates of SM invasion and lymph node metastasis among Ⅰp type lesions, and show malignant potential. However, there was no significant difference in the rate of lymph node metastasis between the Ⅰp＋Ⅱc type early cancers and the 147 depressed-type SM cancers. In one patient with Ⅰp＋Ⅱc type lesion who was followed for 22 months, the stalk disappeared, and the Ⅰp＋Ⅱc type lesion changed to Ⅰs＋Ⅱc type and then to Ⅱa＋Ⅱc type T1b cancer. The second case changed from Ⅰp＋Ⅱc to Ⅱa＋Ⅱc type T1b cancer over the course of 22 days. In conclusion, the Ⅰp＋Ⅱc type early colorectal cancer showed a specific growth pattern of depressed-type cancer that developed primarily at the sigmoid colon, and it showed the biological behavior of depressed-type colorectal cancers.
