FEMALES diagnosed with breast cancer and carrying harmful BRCA gene mutations face higher overall mortality risk, if the diagnosis occurs within a decade after giving birth. The study adds to the growing evidence suggesting that the time following childbirth poses a heightened risk for the development and aggressive progression of breast cancer. Meta-analyses focusing on young females diagnosed with breast cancer within 10 years postpartum consistently showed an increased likelihood of cancer spreading to distant sites, as well as mortality. Given the significant impact of recent childbirth on breast cancer outcomes in the general population, it is important to explore whether females with inherited BRCA mutations experience similar poor prognoses.
Zhenzhen Zhang, Division of Oncological Sciences, Knight Cancer Institute, Oregon Health & Science University, Portland, USA, and colleagues, analysed the data of 903 females (median age of diagnosis: 34.7 years) with BRAC1 and BRAC2 gene mutations who were diagnosed with Stage I–III breast cancer between the ages of 15–45 years in the UK. All participants had comprehensive information regarding the time elapsed since their most recent childbirth. The researchers examined the duration between the latest childbirth and the subsequent diagnosis of breast cancer, studying its correlation with overall mortality rates.
Over a mean follow-up duration of 10.8 years, 419 females were diagnosed with breast cancer within 10 years after childbirth. Among them, 228 were diagnosed within <5 years postpartum, while 191 were diagnosed between 5 to less than 10 years postpartum.
Those diagnosed with breast cancer within 5 to less than 10 years after childbirth faced an increased risk of all-cause mortality compared to those who hadn’t given birth and those diagnosed 10 years or more postpartum (hazard ration [HR]: 1.56; 95% confidence interval [CI]: 1.05–2.30). When compared to females who had not given birth, those with oestrogen receptor-positive breast cancer diagnosed within 5 years postpartum had a higher risk of all-cause mortality (HR: 2.35; 95% CI: 1.02–5.42), while those with oestrogen receptor-negative breast cancer diagnosed within 5 to less than 10 years postpartum had an even greater risk (HR: 3.12; 95% CI: 1.22–7.97).
Furthermore, among females diagnosed within 5 to less than 10 years postpartum, those carrying the BRCA1 gene had a higher risk of all-cause mortality compared to those with the BRCA2 gene (HR: 2.03; 95% CI: 1.15–3.58).
The researchers noted that taking into account how childbirth might affect breast cancer outcomes in young females with inherited harmful BRCA gene mutations could enhance the quality of care in genetic counselling, disease prevention, and clinical settings.
Reference
Zhang Z et al. Postpartum breast cancer and survival in women with germline BRCA pathogenic variants. JAMA Netw Open. 2024;7(4):e247421.
