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

Abstract

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/m2. 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.

Comprehensive evaluation of the incidence of late effects in 5-year survivors of breast cancer

“…With this improving survival, patient and provider attention has shifted toward late effects of breast cancer among long-term survivors [1,2]. Using the cohort of older breast cancer survivors, and their matched comparison cohort, we have previously reported on the relative incidence of heart disease [17], fractures [18], cancer [16], and the comorbid conditions included in the Charlson index (Jordan et al , submitted). Given the administrative setting from which cohort members were identified, we recognized that we could evaluate the complete spectrum of ICD-coded diseases, conditions, and symptoms with marginal effort and cost.…”

“…We matched members of a breast cancer free comparison cohort to the members of the breast cancer survivor cohort [16]. Comparison members were selected from women enrolled in the health plan at least one year before the matched breast cancer patient's diagnosis date, to satisfy the same enrollment criterion as applied to breast cancer patients.…”

“…The Long-term Survivorship in Older Women with Early Stage Breast Cancer study has constructed a cohort of older breast cancer patients treated in integrated health care systems [15], and a matched cohort of women free of breast cancer [16]. We have investigated whether the breast cancer survivors are at risk for heart disease [17], fractures [18], cancer [16], and the diseases included in the Charlson index (Jordan et al , submitted).…”

“…We have investigated whether the breast cancer survivors are at risk for heart disease [17], fractures [18], cancer [16], and the diseases included in the Charlson index (Jordan et al , submitted). Given our access to administrative databases containing healthcare information for all members of both cohorts, we recognized the potential to investigate the association between breast cancer survivorship and a comprehensive set of late events.…”

Relative mortality rates from incident chronic diseases among breast cancer survivors – A 14year follow-up of five-year survivors diagnosed in Denmark between 1994 and 2007

“…Patients with comorbidity potentially receive a modified course of treatment and have poorer survival than otherwise healthy breast cancer patients [4][5][6][9][10][11][12]. Recent studies from the United States documented that older five-year breast cancer survivors have approximately similar incidence of new medical conditions as agematched women from the general population [13][14][15]. Incident diseases were associated with seven-fold increased mortality among women from the general population but only four-fold among the breast cancer survivors [13].…”