Risk factors for breast cancer and their association with molecular subtypes in a population of Northeast Brazil

The unique risk factor profile of triple-negative breast cancer: a comprehensive meta-analysis

BACKGROUND

Triple-negative breast cancer (TNBC) has a poor prognosis compared with other breast cancer subtypes. This systematic review and meta-analysis examines whether known risk factors for breast cancer are also associated with TNBC in adult women.

METHODS

EMBASE, Medline, SCOPUS, and gray literature were queried with no limit on the date or language of publication. The exposures of interest included parity, breastfeeding, duration of breastfeeding, age at menarche, age at first live birth, oral contraceptive (OC) use, duration of OC use, use of menopausal hormone therapy (MHT), family history, body mass index (BMI), alcohol use, smoking, and breast density. The main outcome of interest was TNBC. Study quality was determined using the Newcastle-Ottawa scale for case control studies and cohort studies. We estimated weighted odds ratios from random effects models to study the exposure-outcome associations. Protocol was registered under the number: PROSPERO 2021 CRD42021254594.

RESULTS

Thirty-three studies were included. Family history, longer duration of OC use, and higher breast density were significantly associated with increased risk for TNBC, whereas later age at menarche, later age at first birth, and breastfeeding were protective against TNBC. Parity, MHT, alcohol, smoking, and BMI were not significantly associated with TNBC overall, but higher parity was associated with higher risk among Black women.

CONCLUSION

Our findings highlight that TNBC has a distinct risk factor profile compared with overall breast cancer. This can be the foundational work in identification of actionable TNBC risk factors to improve prevention and early detection of these poor prognosis breast tumors.

Cancer Risk Factors in Southern Brazil: Report of a Comprehensive, Matched Case-Control Study

PURPOSE

To evaluate cancer risk factors among cancer cases and controls from Southern Brazil, to analyze a multigene hereditary panel testing (MGPT, 26 genes) for breast cancer (BC) and colorectal cancer (CCR) cases diagnosed age younger than 50 years and to characterize them for hereditary cancer syndrome (HCS) phenotypes.

METHODS

A case-control (matched by age group and sex) study was conducted on regional cancer. Data on exposure factors and first-/second-degree family history of cancer (1/2FHC) were collected. The MGPT was performed using Illumina next-generation sequencing technology.

RESULTS

A total of 1,007 cases and 1,007 controls were included. The most frequent cancers were BC (n = 311), CCR (n = 147), prostate (n = 132), and lung cancers (n = 89). It was independently associated with cancer, 1/2FHC, tobacco consumption (TC), pesticide exposure (PE), solvent/glue exposure, and BMI <24. BC was associated with 1/2FHC, TC, and hormone replacement therapy use; CCR with 1/2FHC, TC, and BMI <24; prostate cancer with 1/2FHC, TC, and alcohol consumption; and lung cancer with 1/2FHC, TC, PE, and BMI <24. MGPT identified pathogenic/likely pathogenic mutations in 24 (32%) women with BC and in three (18%) women and four (24%) men diagnosed with CCR at under 50 years. Among the tested patients under 50 years with diagnosed BC and CCR, 98.6% and 97% present criteria for HCS, respectively.

CONCLUSION

This study confirmed the association of several factors associated with BC, CCR, prostate, and lung cancers and reinforced the importance of evaluating FHC and genetic testing, especially for patients under 50 years with diagnosed BC or CCR. A better understanding of population-specific cancer risk factors builds on sustainable data for developing prevention strategies. These efforts increase the commitment to early detection and surveillance.