- Interval breast cancers (a breast cancer diagnosed between 2 mammographic screenings) are associated with greater likelihood of other tumor types both before and after the detection of the interval breast cancer, according to a combined analysis of 2 Swedish cohorts and 1 American cohort.
Why this matters
- Clinicians should maintain a high index of suspicion for tumors of other types when interval breast cancers are diagnosed.
- Prospective combined cohort (n=14,846) study consisting of 3 cohorts: KARMA, LIBRO (both Swedish), and the Women's Health Initiative (the American cohort).
- Funding: Swedish Research Council; NIH; others.
- The combined cohort consisted of 11.9% (n=1771) interval breast cancers and 88.1% (n=13,074) screen-detected breast cancers.
- Interval breast cancer patients were more likely than screen-detected breast cancer patients to:
- Have nonbreast cancer tumor before the interval diagnosis (OR, 1.43; 95% CI, 1.19-1.70).
- Have nonbreast cancer tumor after the interval diagnosis (OR, 1.28; 95% CI, 1.14-1.44).
- Report a family history of nonbreast cancer tumors (OR, 1.94; 95% CI, 1.00-3.68).
- Have a lower genetic risk score based on common variants for 12 different nonbreast cancer tumors (OR per standard deviation, 0.85; 95% CI, 0.76-0.95).
- Observational design.