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Incident malignancies among older long‐term breast cancer survivors and an age‐matched and site‐matched nonbreast cancer comparison group over 10 years of follow‐up
Author(s) -
CloughGorr Kerri M.,
Thwin Soe Soe,
Bosco Jaclyn L. F.,
Silliman Rebecca A.,
Buist Diana S. M.,
Pawloski Pamala A.,
Quinn Virginia P.,
Prout Marianne N.
Publication year - 2012
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.27914
Subject(s) - medicine , breast cancer , cancer , cancer registry , malignancy , incidence (geometry) , comorbidity , national death index , proportional hazards model , body mass index , demography , hazard ratio , confidence interval , physics , sociology , optics
BACKGROUND: Of the approximately 2.4 million American women with a history of breast cancer, 43% are aged ≥65 years and are at risk for developing subsequent malignancies. METHODS: Women from 6 geographically diverse sites included 5‐year breast cancer survivors (N = 1361) who were diagnosed between 1990 and 1994 at age ≥65 years with stage I or II disease and a comparison group of women without breast cancer (N = 1361). Women in the comparison group were age‐matched and site‐matched to breast cancer survivors on the date of breast cancer diagnosis. Follow‐up began 5 years after the index date (survivor diagnosis date or comparison enrollment date) until death, disenrollment, or through 15 years after the index date. Data were collected from medical records and electronic sources (cancer registry, administrative, clinical, National Death Index). Analyses included descriptive statistics, crude incidence rates, and Cox proportional hazards regression models for estimating the risk of incident malignancy and were adjusted for death as a competing risk. RESULTS: Survivors and women in the comparison group were similar: >82% were white, 55% had a Charlson Comorbidity Index of 0, and ≥73% had a body mass index ≤30 kg/m 2 . Of all 306 women (N = 160 in the survivor group, N = 146 in the comparison group) who developed a first incident malignancy during follow‐up, the mean time to malignancy was similar (4.37 ± 2.81 years vs 4.03 ± 2.76 years, respectively; P = .28), whereas unadjusted incidence rates were slightly higher in survivors (1882 vs 1620 per 100,000 person years). The adjusted hazard of developing a first incident malignancy was slightly elevated in survivors in relation to women in the comparison group, but it was not statistically significant (hazard ratio, 1.17; 95% confidence interval, 0.94‐1.47). CONCLUSIONS: Older women who survived 5 years after an early stage breast cancer diagnosis were not at an elevated risk for developing subsequent incident malignancies up to 15 years after their breast cancer diagnosis. Cancer 2013. © 2012 American Cancer Society.