Subsequent Colorectal Cancer Risk among Women with Gynecologic Cancer-A Population Cohort Study

• Main Authors: Szu-Chia Liao, 廖思嘉
• Other Authors: Fung-Chang Sung
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/00723677035925795251

碩士 === 中國醫藥大學 === 公共衛生學系碩士班 === 102 === Background: Recent studies have shown that gynecologic malignancy survivors are at higher risk of subsequent primary cancers. However, studies on the subsequent colon cancer risk have revealed controversial results, especially in the association with cervical cancer. The effect of radiotherapy (RT) and chemotherapy (CT) on the occurrence of subsequent colon cancer remains unclear. This study evaluated the relationship between the gynecologic cancers and subsequent colon cancer and colon polyps (precancerous tumors), with the consideration of the treatment effects of radiotherapy and chemotherapy. We sought to propose an optimal colon screening program for these survivors from this study. Method: We performed a population-based retrospective cohort study using data obtained from National Health Research Institutes for the period from 1998 to 2009 to established a gynecological cancer cohort consisting of patients with cervical cancer (N = 25370), endometrial cancer (N = 8149) and ovarian cancer (N = 7933). A comparison cohort (N = 165808) without cancer was randomly selected frequency matched by age and disease date. We calculated incidence rates of subsequent colon cancer and subsequent polypectomy for both cohorts after one-year survival. Gynecologic cancer patients were stratified into groups by radiotherapy and chemotherapy for measuring the risk of colon cancer and polypectomy by the end of 2010. The Cox proportional hazards regression model was used to estimate the hazard ratio (HR) of colorectal cancer and polypectomy associated with the gynecologic cancers. We also used the Kaplan–Meier survival analysis to estimate the proportions of subjects with these three studied cancers developing subsequent colon cancers or polypectomy during the follow-up period in both cohorts. Results: Overall, 41452 women with one-year survivors of these gynecologic cancers were included for data analysis. The incidence rates of colorectal cancer in those with cervical, endometrial and ovarian cancers were 1.26-, 2.20-, and 1.61-fold higher than that in the general population (1.09 per 10,000 person-years). Overall, the corresponding adjusted HRs for developing colorectal cancers were 1.20 (95% CI: 1.03-1.40), 2.26 (95% CI: 1.77-2.90), and 2.09 (95% CI: 1.59-2.76), respectively. The incidences of polypectomy were higher in women with these gynecologic cancers than general women, but not significant. The respective cancer-to-reference colorectal cancer incidence rate ratio was age dependent. In women with cervical cancer, the highest adjusted HR of colorectal cancer was 1.67 (95% CI 1.13-2.48) found for those aged 40-49 years old, followed by those aged 50-64 years old (adjusted HR 1.32, 95% CI 1.02-1.70). In women with endometrial and ovarian cancers 30-39 years of ages had the highest risk of colorectal cancer with adjusted HRs of 6.18 (95% CI: 2.11-18.1) and 6.37 (95% CI: 2.71–15.0), respectively, followed by those women aged 40-49 years, with adjusted HRs of 3.46 (95% CI: 2.05-5.84) and 2.83 (95% CI: 1.59–5.01). Among cancer patients receiving different therapeutic modalities, endometrial cancer patients receiving chemotherapy alone had the highest adjusted HR of 3.39 (95% CI: 1.69–6.80). Colorectal cancer appeared to be higher in the first three years for women after being diagnosed with endometrial and ovarian cancers (p <0.0001). The increased incidence of colorectal cancer appeared during 4th-7th years after women with cervical cancer diagnosed (p <0.0001). Conclusion: Patients with gynecologic cancers are at an increased risk of developing colorectal cancers, the relative hazard is higher in the younger gynecologic cancers patients. Women receiving chemotherapy are also at higher risk, especially for those with endometrial cancer.