Breast cancer and age in Black and White women in South East England Ruth H. Jack, Elizabeth A. Davies and Henrik Møller King’s College London, Thames Cancer Registry, London, United Kingdom Black women have lower age-standardized breast cancer incidence rates than White women in the United Kingdom. However, little is known about such differences in risk in separate age groups. Records on female residents of South East England diagnosed with breast cancer between 1998 and 2003 were extracted from the Thames Cancer Registry database. Age-specific incidence rates were calculated for each 5-year age group using 2001 Census population data for White, Black Caribbean and Black African women. Black Caribbean and Black African breast cancer patients were younger than both the White patients and those with no ethnicity recorded. Black Caribbean and Black African women in the population also had a younger age profile than White women. The computed age-specific incidence rates in women aged under 50 were similar in the different ethnic groups, whereas in women aged 50 and over White women had higher rates. The younger age of Black Caribbean and Black African breast cancer patients in South East England reflects the younger age of these populations, rather than an increased risk of disease at younger ages. Age-adjusted breast cancer incidence rates are lower in Black women than White women in the United States 1,2 and the United Kingdom. 3,4 A higher age-specific incidence rate in Black women aged under 40 has been reported in the United States. 5–8 A hospital study in North East London reported that Black women with breast cancer were younger than White breast cancer patients. 9 However, the local population data were only available for broad age groups. 10 A large popula- tion-based study has not yet investigated the risk of breast cancer in different age groups in the United Kingdom. This study therefore aimed to examine whether there is a differ- ence in the age at which Black Caribbean, Black African and White women are diagnosed with breast cancer that is unre- lated to differences in the population age structures. Material and Methods In the United Kingdom, cancer registries record the occur- rence of cancer in their resident populations. In the area cov- ered by the Thames Cancer Registry, registration is initiated by clinical and pathological information received from hospi- tals and by information about deaths provided by the National Health Service (NHS) Central Register through the Office for National Statistics. Trained cancer registration offi- cers then extract further information on demographic details, disease stage and treatment from the medical records. Data are quality assured as they are added to the central database. Hospital Episode Statistics (HES) data come from hospital Patient Administration Systems and include patient, clinical, administrative and geographical details. Self-assigned ethnic- ity was introduced to the HES data in April 1995 using the codes from the England and Wales Census. Records on female breast cancer cases resident in South East England who were diagnosed between 1998 and 2003 were extracted from the Thames Cancer Registry database. Ethnicity information from inpatient HES records was linked to the registry records using NHS number (a unique person identifier), or sex, date of birth and postcode of residence. If there was no link, ethnicity information routinely recorded by the Thames Cancer Registry was used, if available. Popula- tion data on female residents of the same area of South East England were obtained from the 2001 Census (the most recent England and Wales census) by age and ethnic group. Age-specific rates were calculated for each 5-year age group, and age-standardized incidence rate ratios (ASRRs) were cal- culated for Black Caribbean and Black African women com- pared with the baseline of White women in 10-year age groups. The ASRRs are therefore the ratio of breast cancer incidence in Black Caribbean or Black African women com- pared with White women of the same age. Results There were 31,698 White, 659 Black Caribbean and 345 Black African women diagnosed with breast cancer between 1998 and 2003. During this period there were also 20,079 female South East England residents diagnosed with breast cancer who had no ethnicity recorded. The proportion of women without ethnicity information varied by age: 31% of Key words: breast cancer, ethnicity, age DOI: 10.1002/ijc.26088 History: Received 8 Dec 2010; Accepted 10 Mar 2011; Online 28 Mar 2011 Correspondence to: Ruth H. Jack, King’s College London, Thames Cancer Registry, 1st Floor Capital House, 42 Weston Street, London, UK, SE1 3QD, Tel. þ[44 (0)20 7378 7688], E-mail: ruth.jack@kcl.ac.uk Short Report Int. J. Cancer: 130, 1227–1229 (2012) V C 2011 UICC International Journal of Cancer IJC