Screen detection of ductal carcinoma in situ and subsequent incidence of invasive interval breast cancers: a retrospective population-based study.

BACKGROUND: The value of screen detection and treatment of ductal carcinoma in situ (DCIS) is a matter of controversy. At present, the extent to which the diagnosis and treatment of DCIS could prevent the occurrence of invasive breast cancer in the future is not clear. We sought to estimate the association between detection of DCIS at screening and invasive interval cancers subsequent to the relevant screen. METHODS: We obtained aggregate data for screen-detected cancers from 84 local screening units within 11 regional Quality Assurance Reference Centres in England, Wales, and Northern Ireland from the National Health Service Breast Screening Programme. Data for DCIS diagnoses were obtained for women aged 50-64 years who were invited to and attended mammographic breast screening from April 1, 2003, to March 31, 2007 (4 screening years). Patient-level data for interval cancer arising in the 36 months after each of these were analysed by Poisson regression with invasive interval cancer screen detection rate as the outcome variable; DCIS detection frequencies were fitted first as a continuous and then as a categorical variable. We repeated this analysis after adjustment with both small size and high-grade invasive screen-detected cancers. FINDINGS: We analysed data for 5,243,658 women and on interval cancers occurring in the 36 months after the relevant screen. The average frequency of DCIS detected at screening was 1·60 per 1000 women screened (median 1·50 [unit range 0·54-3·56] [corrected to] per 1000 women). There was a significant negative association of screen-detected DCIS cases with the rate of invasive interval cancers (Poisson regression coefficient -0·084 [95% CI -0·13 to -0·03]; p=0·002). 90% of units had a DCIS detection frequency within the range of 1·00 to 2·22 per 1000 women; in these units, for every three screen-detected cases of DCIS, there was one fewer invasive interval cancer in the next 3 years. This association remained after adjustment for numbers of small screen-detected invasive cancers and for numbers of grade 3 invasive screen-detected cancers. INTERPRETATION: The association between screen-detected DCIS and subsequent invasive interval cancers suggests that detection and treatment of DCIS is worthwhile in prevention of future invasive disease. FUNDING: UK Department of Health Policy Research Programme and NHS Cancer Screening Programmes.

The varying influence of socioeconomic deprivation on breast cancer screening uptake in London.

BACKGROUND: We assessed the relationship between screening uptake and socioeconomic deprivation for London women aged 50-52 invited to their first routine screening appointment between 2006 and 2009. METHODS: We examined uptake for London overall and within six screening areas, using deprivation quintile, based on post code of residence. RESULTS: After adjustment for age, area and ethnicity, overall uptake decreased with increasing deprivation (adjusted odds ratio (OR) = 0.95, P < 0.001). However, in two screening areas with lower uptake, women living in deprived areas had higher uptake than women from affluent areas. CONCLUSIONS: These potential inequalities in early diagnosis across London require further investigation.

Breast cancer screening uptake among women from different ethnic groups in London: a population-based cohort study.

OBJECTIVE: To use newly available self-assigned ethnicity information to investigate variation in breast cancer screening uptake for women from the 16 specific ethnic groups within the broad Asian, Black and White groups that previous studies report. SETTING: National cancer screening programme services within London. PARTICIPANTS: 655,516 female residents aged 50-69, invited for screening between March 2006 and December 2009. Ethnicity information was available for 475,478 (72.5%). White British women were the largest group (306,689, 46.8%), followed by Indian (34,687, 5.3%), White Other (30,053, 4.6%), Black Caribbean (25,607, 3.9%), White Irish (17,271, 2.6%), Black African (17,071, 2.6%) and Asian Other (10,579, 1.6%). OUTCOME MEASURES: Uptake for women in different ethnic groups aged 50-52 for a first call invitation to the programme, and for women aged 50-69 for a routine recall invitation after a previous mammography. Uptake is reported (1) for London overall, adjusted using logistic regression, for age at invitation, socioeconomic deprivation and geographical screening area, and (2) for individual areas, adjusted for age and deprivation. RESULTS: White British women attended their first call (67%) and routine recall (78%) invitations most often. Indian women were more likely to attend their first (61%) or routine recall (74%) than Bangladeshi women (43% and 61%, respectively), and Black Caribbean women were more likely than Black African women to attend first call (63% vs 49%, respectively) and routine recall (74% vs 64%, respectively). There was less variation between ethnic groups in some screening areas. CONCLUSIONS: Breast cancer screening uptake in London varies by specific ethnic group for first and subsequent invitations, with White British women being more likely to attend. The variation in the uptake for women from the same ethnic groups in different geographical areas suggests that collaboration about the successful engagement of services with different communities could improve uptake for all women.