[Site-specific colorectal cancer; how is it different?]

A prognostic analysis of 895 cases of stage III colon cancer in different colon subsites

PURPOSE

Stage III colon cancer is currently treated as an entity with a unified therapeutic principle. The aim of the retrospective study is to explore the clinicopathological characteristics and outcomes of site-specific stage III colon cancers and the influences of tumor location on prognosis.

METHODS

Eight hundred ninety-five patients with stage III colon cancer treated with radical operation and subsequent adjuvant chemotherapy (5-fluorouracil/oxaliplatin) were divided into seven groups according to colon segment (cecum, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, and sigmoid colon). Expression of excision repair cross-complementing group 1 (ERCC1) and thymidylate synthase (TS) was examined by immunohistochemistry. We assessed if differences exist in patient characteristics and clinic outcomes between the seven groups.

RESULTS

There were significant differences in tumor differentiation (P < 0.001), T stage (P < 0.001), N stage (P < 0.001), American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) stage (P < 0.001), metachronous liver metastasis (P < 0.001), metachronous lung metastasis (P < 0.001), and ERCCI expression (P < 0.001) between the seven groups. Both 5-year recurrence-free survival (RFS) and 5-year overall survival (OS) exhibited significant differences (both P < 0.001) with survival gradually decreasing from cecum to sigmoid colon. Cox regression analyses identified that tumor location was an independent prognostic factor for RFS and OS.

CONCLUSIONS

Stage III colon cancer located proximally carried a poorer survival than that located distally. Different efficacies of FOLFOX adjuvant chemotherapy may be an important factor affecting survival of site-specific stage III colon cancers.

Ileocaecal junction carcinoma: a clinicopathological study of 199 cases

AIM

The ileocaecal junction (ICJ) region is an epithelial transition zone in which carcinomas are frequently diagnosed. However, it is currently unknown whether ICJ carcinomas (ICJ-CAs) have distinctive features. This study aimed to characterize the clinicopathological features of ICJ-CAs.

METHOD

All ileal and colorectal resections for carcinoma, performed in Calgary, Canada between January 2009 and June 2012, were reviewed. Carcinomas in which the epicentre was within 5 cm of the ileocaecal valve (ICV) were defined as ICJ-CAs. Of 1003 carcinomas studied, 199 (19.8%) were ICJ-CAs, including 93 (9.3%) that crossed the ICV. Comparison of clinicopathological features with carcinomas of the other ileo-colorectal regions was made. Survival was also assessed.

RESULTS

Clinically, ICJ-CAs were more common in female than male patients (56.3% female) compared with left-colonic (42.9% female) and rectal (37.9% female) carcinomas, and were more common in older age-groups of patients (71.8 ± 12.7 years) compared with appendiceal (62.6 ± 11.3 years), left-colonic (69.4 ± 12.3 years) and rectal (67.1 ± 11.9 years) carcinomas. Macroscopically, ICJ-CAs were similar to other colorectal carcinomas and were mostly described as ulcerated (63.3%). Histologically, ICJ-CAs had more mucinous, signet-ring cell and/or neuroendocrine features (39.7%, 8.0% and 7.5%, respectively) than did carcinomas of the left colon (16.8%, 1.6% and 1.1%, respectively) and the rectum (14.1%, 1.0% and 0.0%, respectively). They were higher grade (20.1% were high grade) than those of the left-colon (10.3%) and the rectum (9.8%). ICJ-CAs presented at a higher T-stage (25.6% were T4) compared with rectal carcinomas (11.6%). Most significantly, ICJ-CAs presented at a higher N-stage (25.6% were N2) than did right-colonic (14.1%) and rectal (16.2%) carcinomas. Although survival of patients with ICJ-CAs did not differ from those with right-colonic carcinomas, those with carcinomas directly involving the ICV did show a significantly decreased survival.

CONCLUSION

ICJ-CAs display several distinct clinicopathological features that may require special diagnostic, prognostic and management attention.