Age, sex and the risk of grade-specific second primary colorectal cancer: evidence for the protective effect of female hormone.
OBJECTIVE
To investigate the interaction effects of age and sex on the risk of grade-specific second primary colorectal cancer (SPCRC).


METHODS
This is a retrospective cohort study, using registry data covering the period 1973-2003 from the SEER program, National Cancer Institute. The sex-age-specific incidence rates of Grade 1, Grade 2 and Grade 3 second primary colorectal cancer (SPCRC) were calculated. Poisson regression models were used to estimate the interaction effects between sex and age.


RESULTS
The sex-age-specific incidence rates of Grade 1, Grade 2, and Grade 3 second primary colorectal cancer (SPCRC) increased gradually with age, especially in females. There was a significant interaction effect between sex and age on the risk of Grade 3 second primary colon cancer.


CONCLUSIONS
Decrease in female hormone level since menopausal age may increase the risk of a second primary colon cancer, especially a cancer with poorer differentiation.
Liang
Wenbin
W
School of Public Health, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia. wenbin.liang@postgrad.curtin.edu.au
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D004967:Estrogens / Q000378:metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors
D004967:Estrogens