Is Family History Associated With Breast Cancer Prognosis in Sweden?

By: Chris Schimpf, BS
Posted: Wednesday, September 6, 2023

Citing conflicting data, Yuqi Zhang, PhD, of the Karolinska Institute, Stockholm, and colleagues conducted a cohort study to evaluate whether family history may be associated with the prognosis of overall and estrogen receptor (ER)-specific breast cancer in female patients in Sweden. Their findings, reported in JAMA Network Open, suggest that individuals with family histories of breast cancer did not necessarily have worse outcomes and that some may have better outcomes—possibly related to motivation to receive and adhere to treatment. The researchers reported that patients with ER-negative breast cancer and a family history of breast cancer had more favorable outcomes in the first 5 years after diagnosis, but patients with a family history of early-onset breast cancer had worse outcomes.

“To our knowledge, this study included one of the largest and most well-characterized cohorts of patients with breast cancer,” the investigators stated. “The data…can be used as a starting point for further studies addressing issues such as the cost-effectiveness of breast cancer variant screening for all newly diagnosed patients who have early-onset family history.”

A total of 28,649 women with breast cancer were included in the study, drawn from multiple national registers in Sweden. Overall, 17.7% had at least one female first-degree relative diagnosed with breast cancer, and 1.3% had a family history of early-onset breast cancer (defined as a first-degree relative diagnosed before the age of 40). During the follow-up period, 9.6% died of breast cancer. Multivariable analyses revealed that a family history of breast cancer was associated with a lower risk of breast cancer–specific death among the full cohort (hazard ratio [HR] = 0.78; 95% confidence interval [CI] = 0.65–0.95) and those with ER-negative breast cancer (HR = 0.57; 95% CI = 0.40–0.82) in the first 5 years, after which no association was observed. However, an early-onset family history was associated with a higher risk of breast cancer–specific death (HR = 1.41; 95% CI = 1.03–2.34).

Disclosure: The study authors reported no conflicts of interest.

JAMA Network Open