TY - JOUR
T1 - Divergent oestrogen receptor-specific breast cancer trends in Ireland (2004–2013)
T2 - Amassing data from independent Western populations provide etiologic clues
AU - Mullooly, Maeve
AU - Murphy, Jeanne
AU - Gierach, Gretchen L.
AU - Walsh, Paul M.
AU - Deady, Sandra
AU - Barron, Thomas I.
AU - Sherman, Mark E.
AU - Rosenberg, Philip S.
AU - Anderson, William F.
N1 - Publisher Copyright:
© 2017
PY - 2017/11
Y1 - 2017/11
N2 - The aetiology and clinical behaviour of breast cancers vary by oestrogen receptor (ER) expression, HER2 expression and over time. Data from the United States and Denmark show rising incidence rates for ER+ and falling incidence rates for ER– breast cancers. Given that Ireland is a somewhat similar Western population but with distinctive risk exposures (especially for lactation), we analysed breast cancer trends by ER status; and for the first time, by the joint expression of ER±/HER2±. We assessed invasive breast cancers (n = 24,845; 2004–2013) within the population-based National Cancer Registry of Ireland. The population at risk was obtained from the Irish Central Statistics Office (n = 10,401,986). After accounting for missing ER and HER2 data, we assessed receptor-specific secular trends in age-standardised incidence rates (ASRs) with the estimated annual percentage change (EAPC) and corresponding 95% confidence intervals (95% CI). Age-period-cohort models were also fitted to further characterise trends accounting for age, calendar-period and birth-cohort interactions. ASRs increased for ER+ (EAPC: 2.2% per year [95% CI: 0.97, 3.45%/year]) and decreased for ER– cancers (EAPC: −3.43% per year [95% CI: −5.05, −1.78%/year]), as well as for specific age groups at diagnosis (<30–49, 50–64 and ≥65 years). ER+/HER2– cancers rose, ER+/HER2+ cancers were statistically flat and ER–/HER± cancers declined. Secular trends for ER± cancers in Ireland were like those previously observed. Stratification by HER2± expression did not substantively alter ER± trends. The divergence of ER± incidence rates among independent Western populations likely reflects calendar-period and/or risk factor changes with differential effects for ER+ and ER– breast cancers.
AB - The aetiology and clinical behaviour of breast cancers vary by oestrogen receptor (ER) expression, HER2 expression and over time. Data from the United States and Denmark show rising incidence rates for ER+ and falling incidence rates for ER– breast cancers. Given that Ireland is a somewhat similar Western population but with distinctive risk exposures (especially for lactation), we analysed breast cancer trends by ER status; and for the first time, by the joint expression of ER±/HER2±. We assessed invasive breast cancers (n = 24,845; 2004–2013) within the population-based National Cancer Registry of Ireland. The population at risk was obtained from the Irish Central Statistics Office (n = 10,401,986). After accounting for missing ER and HER2 data, we assessed receptor-specific secular trends in age-standardised incidence rates (ASRs) with the estimated annual percentage change (EAPC) and corresponding 95% confidence intervals (95% CI). Age-period-cohort models were also fitted to further characterise trends accounting for age, calendar-period and birth-cohort interactions. ASRs increased for ER+ (EAPC: 2.2% per year [95% CI: 0.97, 3.45%/year]) and decreased for ER– cancers (EAPC: −3.43% per year [95% CI: −5.05, −1.78%/year]), as well as for specific age groups at diagnosis (<30–49, 50–64 and ≥65 years). ER+/HER2– cancers rose, ER+/HER2+ cancers were statistically flat and ER–/HER± cancers declined. Secular trends for ER± cancers in Ireland were like those previously observed. Stratification by HER2± expression did not substantively alter ER± trends. The divergence of ER± incidence rates among independent Western populations likely reflects calendar-period and/or risk factor changes with differential effects for ER+ and ER– breast cancers.
KW - Breast cancer
KW - HER2
KW - Incidence rates
KW - Oestrogen receptor
KW - Secular trends
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U2 - 10.1016/j.ejca.2017.08.031
DO - 10.1016/j.ejca.2017.08.031
M3 - Article
C2 - 29073583
AN - SCOPUS:85032873932
SN - 0959-8049
VL - 86
SP - 326
EP - 333
JO - European Journal of Cancer
JF - European Journal of Cancer
ER -