Erin Roesch, MD
A positive family history of cancer and obesity are established risk factors for development of breast cancer among women.[4,5] A population-based cohort study that included 15,055 Chinese women evaluated the association and interaction between body mass index (BMI) and family history of cancer on the risk for breast cancer (Cao et al). The incidence risk for breast cancer was highest in the group with obesity vs the group with normal weight (adjusted HR 2.09; 95% CI 1.42-3.07), and those with a family history of cancer also had an increased risk vs those without a family history of cancer (adjusted HR 1.63; 95% CI 1.22-2.49). Furthermore, women with a BMI ≥ 24 and family history of cancer had a higher risk for breast cancer development compared with women with a BMI < 24 and no family history of cancer (adjusted HR 2.06; 95% CI 1.39-3.06). This study indicates a heightened breast cancer risk when cancer family history and obesity coexist, suggesting the importance of addressing modifiable risk factors and targeting lifestyle interventions in this population.
Triple-negative breast cancer (TNBC), although exhibiting its own heterogeneity, has various features that differentiate this subtype from luminal breast cancers. For example, TNBC generally has a more aggressive course, increased responsiveness to chemotherapy, and earlier pattern of recurrence compared with hormone receptor–positive disease. Prior studies have also shown that established breast cancer risk factors reflect those for the luminal A subtype, whereas those for TNBC are less consistent.[6] A meta-analysis that included 33 studies evaluated the association between traditional breast cancer risk factors and TNBC incidence (Kumar et al). Family history (odds ratio [OR] 1.55; 95% CI 1.34-1.81; P < .001), longer duration of oral contraceptive use (OR 1.29; 95% CI 1.08-1.55; P < .001), and higher breast density (OR 2.19; 95% CI 1.67-2.88; P < .001) were significantly associated with an increased risk for TNBC. Factors including later age at menarche, later age at first birth, and breastfeeding were associated with reduced risk for TNBC. Furthermore, there was no significant association with parity, menopausal hormone therapy, alcohol, smoking, and BMI. This study highlights distinct risk factors that may contribute to a higher risk for TNBC, and future research will be valuable to better elucidate the mechanisms at play and to further understand the differences within this subtype itself.
Additional References
- National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology. Genetic/familial high-risk assessment: breast, ovarian, and pancreatic. Version 3.2024. Source
- Saadatmand S, Geuzinge HA, Rutgers EJT, et al; on behalf of the FaMRIsc study group. MRI versus mammography for breast cancer screening in women with familial risk (FaMRIsc): A multicentre, randomised, controlled trial. Lancet Oncol. 2019;20:1136-1147. doi: 10.1016/S1470-2045(19)30275-X Source
- Warner E, Zhu S, Plewes DB, et al. Breast cancer mortality among women with a BRCA1 or BRCA2 mutation in a magnetic resonance imaging plus mammography screening program. Cancers (Basel). 2020;12:3479. doi: 10.3390/cancers12113479 Source
- Picon-Ruiz M, Morata-Tarifa C, Valle-Goffin JJ, et al. Obesity and adverse breast cancer risk and outcome: Mechanistic insights and strategies for intervention. CA Cancer J Clin. 2017;67:378-397. doi: 10.3322/caac.21405 Source
- Engmann NJ, Golmakani MK, Miglioretti DL, et al; for the Breast Cancer Surveillance Consortium. Population-attributable risk proportion of clinical risk factors for breast cancer. JAMA Oncol. 2017;3:1228-1236. doi: 10.1001/jamaoncol.2016.6326 Source
- Barnard ME, Boeke CE, Tamimi RM. Established breast cancer risk factors and risk of intrinsic tumor subtypes. Biochim Biophys Acta Rev Cancer. 2015;1856:73-85. doi: 10.1016/j.bbcan.2015.0002 Source