After breast-conserving surgery for invasive breast cancer, women with high breast density tend to have a higher risk of local (within the breast) cancer recurrence than women with low breast density. The effect of breast density is most apparent among women who do not receive radiation therapy. These results were published in the journal Cancer.
Breast density refers to the extent of glandular and connective tissue in the breast. Breasts with more glandular and connective tissue—and less fat—are denser. Women with higher breast density are at increased risk of developing breast cancer. Breast density can be assessed by mammography.
To explore whether breast density influences risk of breast cancer recurrence, researchers reviewed the medical records of 335 women who underwent breast-conserving surgery (lumpectomy) for invasive breast cancer.
Mammographic density was classified as low (<25% density), intermediate (25-50% density), or high (>50% density).
- 10-year risk of local (within the breast) cancer recurrence was 21% among women with high breast density and 5% among women with low breast density.
- The relationship between breast density and risk of local breast cancer recurrence was most apparent in the subset of women who did not receive radiation therapy. In these women the 10-year risk of local recurrence was 40% among women with high breast density and 0% among women with low breast density.
These results suggest that breast density is an important risk factor for local breast cancer recurrence among women who do not receive radiation therapy after breast-conserving surgery.
Reference: Cil T, Fishell E, Hanna W et al. Mammographic density and the risk of breast cancer recurrence after breast-conserving surgery. Cancer [early online publication]. November 9, 2009.