Sex Differences in Colorectal Cancer Survival: Population-Based Analysis of 164,996 Colorectal Cancer Patients in Germany

Abstract

Risk of colorectal cancer (CRC) is considerably higher in men compared to women; however, there is inconclusive evidence of sex differences in CRC prognosis. We aimed to assess and explain sex differences in 5-year relative survival using standard and model-based period analysis among 164,996 patients diagnosed with CRC from 1997 to 2006 and reported to 11 German cancer registries covering a population of 33 million inhabitants. Age-adjusted 5-year relative survival was higher in women (64.5% vs. 61.9%, P<0.0001). A substantial survival advantage of women was confirmed in multivariate analysis after adjusting for CRC stage and subsite in subjects under 65 years of age (relative excess risk, RER 0.86, 95% CI 0.82–0.90), but not in older subjects (RER 1.01, 95% CI 0.98–1.04); this pattern was similar in the 1st and in the 2nd to 5th year after diagnosis. The survival advantage of women varied by CRC stage and age and was most pronounced for localized disease (RERs 0.59–0.88 in various age subgroups) and in patients under 45 years of age (RERs 0.59, 0.72 and 0.76 in patients with localized, regional or advanced disease, respectively). On the contrary, sex differences in survival did not vary by location of CRC. In conclusion, our large population-based study confirmed a survival advantage of female compared to male CRC patients, most notably in young and middle aged patients and patients with localized disease. The effect of sex hormones, either endogenous or through hormonal replacement therapy, might be the most plausible explanation for the observed patterns.

The comparison of predictive factors regarding prognoses and invasion of thymic neuroendocrine tumors preoperatively and postoperatively

“…Besides, the differences in TNT survival by gender probability, NET in other organs, such as esophagus, colon, thyroid, pancreas, and so on, has revealed carcinoid syndrome more frequently in females than in males, and reports have shown that patients with carcinoid syndrome had significantly shorter OS than those without the condition (8,11). Compared with male patients, females had a high incidence of secretion of CRH, ACTH, estrogen (EN) which could (I) enhance the degree of malignancy and the rate of development of TNT, (II) raise the possibility of females having a lower response to adjuvant chemotherapies (8,(11)(12)(13)(14). These factors probably caused female patients to be diagnosed in a relatively advanced stage than male and also disfavored the effectiveness of traditional adjuvant chemotherapies in the treatment of female patients, thus bringing about relatively worse OS in female than male patients.…”

“…However, in our present study, survival rate and OS duration in female patients were significantly poorer than male patients postoperatively. As mentioned above, female TNT patients had worse prognoses because of the factors that affect survival, such as health attitudes, behaviors, influence of bioactive amines (EN, CRH, ACTH), and response to adjuvant therapies, are different between male and female patients (8,(11)(12)(13)(14). Postoperatively, gender was an independent risk factor for OS.…”

Long-term trends in the incidence and relative survival of colorectal cancer in Canada: A population-based study

“…[21] The lower incidence rate of colorectal cancer and the relative survival benefit in women has been replicated across numerous other studies. [20][21][22] Another Canadian study by Gao et…”

“…[20] Similar trends have also been observed in studies from Germany and the Netherlands. [21,22] It has been suggested that the decreased risk of colorectal cancer in women is attributable to female sex hormones. [22] Both endogenous and exogenous hormones (including oral contraceptives and hormone replacement therapy) confer protective effects against colorectal cancer.…”

“…[ 22] In addition, hormone replacement therapy may extend survival in colorectal cancer patients. [22] It is hypothesized that these effects are due to the immune-modulating effects of sex hormones.…”