Trasias Mukama, MPH
In a study reported in JAMA Oncology, Trasias Mukama, MPH, and colleagues identified risk-adapted screening starting ages for relatives of patients with breast cancer according to the number of affected first-degree and second-degree relatives and the age at diagnosis of affected relatives.
The nationwide cohort study analyzed. Swedish family cancer data sets. Women born from 1932 onward with at least one known first-degree relative with breast cancer were included, with data on breast cancer history diagnoses from January 1958 to December 2015 being used in the analysis.
Key Findings
Among the 5,099,172 women included in the study, 118,953 (2.3%) were diagnosed with primary invasive breast cancer. Among the women in this group, 102,751 (86.4%) with a mean age at diagnosis of 55.9 years did not have a family history of breast cancer in first- or second-degree relatives at the time of diagnosis.
The age at which women with a family history of breast cancer attained a risk equal to that of women with average risk (starting guideline-recommended screening at ages 40, 45, and 50 years in the general population) varied according to the number of affected first- and second-degree relatives and the age at diagnosis of affected relatives. For example, the 10-year cumulative risk of invasive breast cancer was 2.2% in women aged 50 years in the general population, an age at which some guidelines recommend the start of mass screening. This level of risk was attained at:
- 45 years of age in women with one affected second-degree relative and no affected first-degree relatives, with no difference in risk according to whether the first-degree relative was from the paternal or maternal side
- 41 years of age in women with one or more affected second-degree relatives and no affected first-degree relatives
- 40 years of age in women with one affected first-degree relative and no affected second-degree relatives
- 38 years of age in women with one affected first-degree relative and one or more affected second-degree relative
- 35 years of age in women with multiple affected first-degree relatives with or without additional affected second-degree relatives
- 27 years of age in women with multiple affected first-degree relatives, with the youngest affected relative having received a breast cancer diagnosis before age 50 years
- 36 years of age in women with multiple affected first-degree relatives, with the youngest affected relative having received a breast cancer diagnosis after age 50 years.
The investigators concluded, “This study identifies possible risk-based starting ages for breast cancer screening based on population-based registers. These results may serve as high-quality evidence to supplement current screening guidelines for relatives of patients with breast cancer.”
Mukama T et al: JAMA Oncol. November 14, 2019 (early release online). ■
