Evaluation of mammographic surveillance services in women aged 40-49 years with a moderate family history of breast cancer: A single-arm cohort study

Background: Women with a significant family history of breast cancer are often offered more intensive and earlier surveillance than is offered to the general population in the National Breast Screening Programme. Up to now, this strategy has not been fully evaluated. Objective: To evaluate the benefit of mammographic surveillance for women aged 40-49 years at moderate risk of breast cancer due to family history. The study is referred to as FH01. Design: This was a single-arm cohort study with recruitment taking place between January 2003 and February 2007. Recruits were women aged < 50 years with a family history of breast or ovarian cancer conferring at least a 3% risk of breast cancer between ages 40 and 49 years. The women were offered annual mammography for at least 5 years and observed for the occurrence of breast cancer during the surveillance period. The age group 40-44 years was targeted so that they would still be aged < 50 years after 5 years of surveillance. Setting: Seventy-four surveillance centres in England, Wales, Scotland and Northern Ireland. Participants: A total of 6710 women, 94% of whom were aged < 45 years at recruitment, with a family history of breast cancer estimated to imply at least a 3% risk of the disease between the ages of 40 and 50 years. Interventions: Annual mammography for at least 5 years. Main outcome measures: The primary study end point was the predicted risk of death from breast cancer as estimated from the size, lymph node status and grade of the tumours diagnosed. This was compared with the control group from the UK Breast Screening Age Trial (Age Trial), adjusting for the different underlying incidence in the two populations. Results: As of December 2010, there were 165 breast cancers diagnosed in 37,025 person-years of observation and 30,556 mammographic screening episodes. Of these, 122 (74%) were diagnosed at screening. The cancers included 44 (27%) cases of ductal carcinoma in situ. There were 19 predicted deaths in 37,025 person-years in FH01, with an estimated incidence of 6.3 per 1000 per year. The corresponding figures for the Age Trial control group were 204 predicted deaths in 622,127 person-years and an incidence of 2.4 per 1000 per year. This gave an estimated 40% reduction in breast cancer mortality (relative risk = 0.60; 95% confidence interval 0.37 to 0.98; p = 0.04). Conclusions: Annual mammography in women aged 40-49 years with a significant family history of breast or ovarian cancer is both clinically effective in reducing breast cancer mortality and cost-effective. There is a need to further standardise familial risk assessment, to research the impact of digital mammography and to clarify the role of breast density in this population. Trial registration: National Research Register N0484114809.