Article
The incidence of colorectal cancers (CRCs) increases with age, and gender plays a part, yet age- and gender-related changes have not been fully investigated, say researchers from University of Tokyo in Japan.
They aimed to clarify gender-specific, age-related changes in the clinicopathologic features of CRCs. The researchers evaluated data on 632 men and 427 women with CRC admitted to the University of Tokyo Hospital from February 2005 to June 2012. Of those patients, 1,036 underwent surgery. Patients with ulcerative colitis, familial adenomatous polyposis, or hereditary nonpolyposis colorectal cancer were excluded from the study. Of the 1,059 patients whose data were analyzed, 98 had ≥ 2 primary CRCs. In those cases, the histopathologic features of the dominant lesion (defined as the largest or deepest) were analyzed. The researchers also assessed the number of concomitant adenomas ≥ 5 mm in diameter.
Among patients aged < 70 years, the female-to-male ratio was relatively low, but increased with age. Male patients with proximal CRC, without distant metastasis and more concomitant adenomas tended to be older. The histologic type was the only variable significantly associated with age in women, but not in men (P = .026).
In the univariate analysis, tumor location was associated with age in both men and women. The shift of tumor location to the proximal colon with increasing age was more prominent in women: Only 11.1% of women aged < 50 years had right-sided CRC, compared with 48.3% of those aged > 80 years. In a multivariate analysis, right-sided CRC was the only independent variable that correlated with age in women aged > 70 years.
The correlation between number of concomitant adenomas and age was stronger in men. In men, the number of concomitant adenomas gradually increased with age, and among those aged > 70 years, 43.2% had ≥ 1 concomitant adenomas, compared with 30.7% of women aged > 70 years.
With increasing age, the proportion of proximal CRC gradually increased in women, whereas that of rectal cancer gradually decreased. To the best of their knowledge, the researchers say, this gradual age-related change of CRC distribution in women has not been previously reported. They don’t know the cause of the connection, but they note that some research has suggested a link between reduced endogenous secretion of female hormones and CRCs in elderly women. Other research has indicated higher expression of estrogen receptor in the epithelium of the right colon compared with that of the left colon; thus, they speculate, the drop in female hormones postmenopause might promote CRC, especially in the right-sided colon.
The higher incidence of concomitant adenomas and the shift for the proximal predominance are the age-related characteristics of CRC in elderly patients, the researchers conclude. They note that chromosomal instability (CIN) is predominantly associated with the adenoma-carcinoma sequence, and microsatellite instability (MSI) with the serrated neoplastic pathway. The results of their study suggest, they say, the importance of CIN in the colorectal carcinogensis of elderly men and, on the other hand, of MSI in that of elderly women.
Source
Iida Y, Kawai K, Tsuno NH, et al. Clin Colorect Canc. 2014;13(4):213-218.
doi: 10.10156/j.clcc.2014.06.005.
