Differences between right- and left-sided colon cancer in patient characteristics, cancer morphology and histology.
OBJECTIVE
Recently, the clinical and biological differences between right- and left-sided colon cancers have been widely debated. However, close analyses of these clinical differences, based on large-scale studies, have been scarcely reported.


METHODS
A total of 3552 consecutive Japanese colorectal cancer cases were examined and the clinical differences between right- and left-sided colon cancer cases were investigated.


RESULTS
The proportion of right-sided colon cancer was relatively high in patients aged less than 40 years (33%) and more than 80 years (43%). The proportion of right-sided colon cancer in patients aged 40-59 years was relatively low (male 22% and female 29%). In male patients the proportion increased in the 70-79 years age group (30%), while in female patients the proportion increased in the 60-69 years age group (39%). Right-sided colon cancer was more likely to be detected at an advanced stage (T1 stage; left 22%, right 15%) (P < 0.01) with severe symptoms. Polypoid-type early cancer was dominant in the left colon (left 59%; right 40%) (P < 0.01), while the proportion of flat-type early cancer in the right colon was significantly higher than that in the left colon (left 25%; right 44%) (P < 0.01).


CONCLUSIONS
Specific age distribution of right-sided colon cancer was observed and the difference between male and female patients was highlighted. Other clinical features also differed between right- and left-sided colon cancer, suggesting that different mechanisms may be at work during right and left colon carcinogenesis.
Nawa
Toru
T
Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. torunawa@yahoo.co.jp
Kato
Jun
J
Kawamoto
Hirofumi
H
Okada
Hiroyuki
H
Yamamoto
Hiroshi
H
Kohno
Hiroyuki
H
Endo
Hisayuki
H
Shiratori
Yasushi
Y
D000230:Adenocarcinoma / Q000473:pathology*; D002288:Adenocarcinoma, Mucinous / Q000473:pathology*; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D018279:Carcinoma, Signet Ring Cell / Q000473:pathology*; D002454:Cell Differentiation; D003110:Colonic Neoplasms / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012042:Registries; D017678:Sex Distribution; D012737:Sex Factors