title: Risk of secondary cancers in women with breast cancer and the influence of radiotherapy: A national cohort study in Taiwan.
abstract: Breast cancer is the most common cancer in women worldwide; thus, the prolongation of survival, and the incidence and risk factors, including radiotherapy, for developing secondary malignancies are important. We compared the incidence of secondary and new primary cancers in women with breast cancer (CA) and well-matched for age, geographic region, and monthly income cancer-free controls (CA). The risk for secondary cancers with and without radiotherapy was also compared in CA women. We enrolled 2422 CA patients and CA 12,110 controls. In a 4-year follow-up, the secondary cancers risk was significant in the CA group (adjusted hazard ratio [AHR]: 1.59; 95% confidence interval [CI]: 1.17-2.18). Only the risk of uterine cancer was significant compared with the controls (AHR: 6.30; 95% CI: 2.28-17.38). CA patients and <50 years old had a higher risk for secondary cancers. Developing secondary cancers was significant in the first follow-up year (AHR: 1.51; 95% CI: 1.11-2.06). Radiotherapy had no significant effect on the CA group, but it was significant (P = 0.0298) in women ≥60 years old (elderly). We recommend monitoring secondary cancers in CA women, especially those <50 years old, and during the first year of follow-up. Radiotherapy should be used more carefully in elderly CA women.
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Chi-Mei Medical Center, Liouying Department of Environmental and Occupational Health, National Cheng Kung University Department of Family Medicine, Chi-Mei Medical Center Department of Emergency Medicine, Chi-Mei Medical Center Department of Child Care and Education, Southern Taiwan University of Science and Technology, Tainan Department of Healthcare Administration and Medical Informatics, Kaohsiung Medical University, Kaohsiung Department of Biotechnology, Southern Taiwan University of Science and Technology Department of Ophthalmology, Chi-Mei Medical Center, Yong Kang Department of Optometry, Chung Hwa University of Medical Technology, Jen-Teh Department of Occupational Medicine, Chi-Mei Medical Center Department of Medical Research, Chi-Mei Medical Center, Liouying, Tainan, Taiwan.
authors.forename: Cheng-Yao
authors.initials: CY
authors.lastname: Lin
authors.forename: Sih-Hao
authors.initials: SH
authors.lastname: Chen
authors.forename: Chien-Cheng
authors.initials: CC
authors.lastname: Huang
authors.forename: Shih-Feng
authors.initials: SF
authors.lastname: Weng
authors.forename: Song-Tay
authors.initials: ST
authors.lastname: Lee
authors.forename: How-Ran
authors.initials: HR
authors.lastname: Guo
authors.forename: Shu-Chun
authors.initials: SC
authors.lastname: Kuo
authors.forename: Shih-Bin
authors.initials: SB
authors.lastname: Su
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000532:radiotherapy; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000209:etiology; D016609:Neoplasms, Second Primary / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors; D016019:Survival Analysis; D013624:Taiwan / Q000453:epidemiology; D014594:Uterine Neoplasms / Q000453:epidemiology* / Q000209:etiology; D055815:Young Adult