Improving the prediction of advanced breast cancer in women of different races and ethnicities

While regular screenings can decrease the chances of being diagnosed with advanced breast cancer in some women and lead to a 20% reduction in breast cancer mortality, other women will be diagnosed with advanced breast cancer despite screening at regular intervals. The chances of being diagnosed with advanced breast cancer are higher among Black or Hispanic/Latinx women as well as overweight and obese women.

In a study published in JAMA Oncology, researchers at UC San Francisco have found that regular screening is not always enough to prevent an advanced diagnosis of breast cancer. To reduce the number of advanced cancer diagnoses, primary prevention is also necessary and should aim to help overweight or obese women achieve a normal weight, particularly women of color.

Advanced breast cancer is defined as American Joint Committee on Cancer prognostic pathologic stage II or higher. Advanced breast cancers are tumors that are large and/or have spread to the lymph nodes or have other characteristics associated with a poorer prognosis, such as being high grade and estrogen receptor negative. They require surgery and systemic treatment, and detecting breast cancers through screening before they become advanced can prevent deaths from breast cancer.

Advanced calculation of breast cancer risk in women who undergo regular screening can guide screening frequency and additional imaging. Clinical risk factors associated with advanced breast cancer include high breast density, high body mass index, age, family history of a first-degree relative with breast cancer, history of biopsies anterior breasts and the postmenopausal state.

Black women have twice the rate of advanced breast cancer as white women among regular screeners.

To assess population attributable risk proportions (PARPs) for advanced breast cancer – the proportion of advanced cancer incidence in the population attributed to a risk factor – researchers conducted a cohort study using data prospectively collected from the Breast Cancer Surveillance Consortium (BCSC) community. territory-based imaging facilities from January 2005 to June 2018.

The participants followed were 904,615 women aged 40 to 74 years (with a median age of 57 years) undergoing 3,331,740 annual or biennial screening mammograms. Among them, 1,815 advanced breast cancers were diagnosed within two years of screening examinations.

Risk factors examined included heterogeneous or extremely dense breasts, family history of first-degree breast cancer, overweight/obesity (body mass index greater than 25), history of benign breast biopsy, and screening interval ( biennial or annual) stratified by menopausal status, race, and ethnicity (Asian or Pacific Islander, Black, Hispanic/Latinx, White, Other/Multiracial).

Body mass index PARPs were higher in postmenopausal women than in premenopausal women (30% vs. 22%) and highest in postmenopausal black women (38.6%) and Hispanic/Latinx women ( 31.8%) as well as in pre-menopausal women. Postmenopausal black women (30.3%). Additionally, the overall prevalence of overweight/obesity was highest among premenopausal (84.4%) and postmenopausal (85.1%) Black women, as well as Hispanic/Latinx women (72.4%).

“Black and Hispanic/Latinx women are at higher risk of being diagnosed with advanced cancer than white, Asian, or Pacific Islander women, and this difference is only partially explained by screening,” said the first author. , Karla Kerlikowske, MD, professor of medicine at UCSF. Medicine and Epidemiology and Biostatistics and Co-PI of the BCSC.

“Identifying the risk factors that account for the largest proportion of advanced breast cancers among people undergoing regular screening and understanding differences in factors associated with advanced cancer risk by race and ethnicity is important to develop personalized and equitable screening strategies and primary preventions. »

Breast density PARPs were greater among premenopausal women than postmenopausal women (37% versus 24%, respectively) and premenopausal white women (39.8%), whose prevalence of dense breasts was high (62%). . For premenopausal and postmenopausal women, PARPs were low in terms of family history of breast cancer (5% to 8%), history of breast biopsy (7% to 12%), and screening interval (2 .1% to 2.3%).

Obesity a bigger risk factor than family history in study

Among regularly screened women, researchers found that screening frequency was a weak risk factor for advanced cancer, and that biannual rather than annual screening accounted for only a small proportion of advanced cancer diagnoses in this study population. . Overweight or obesity accounted for the largest proportion of advanced cancers in postmenopausal women (30%), while dense breasts accounted for the largest proportion of advanced cancers in premenopausal women (37%).

“This is the first study, to our knowledge, to calculate PARPs for advanced breast cancer,” Kerlikowske said. “We found that overweight or obesity accounted for the largest proportion of advanced breast cancers among postmenopausal Black and Hispanic/Latinx women. This contrasts with previous studies, reporting that overweight/obesity accounted for the largest proportion of invasive breast cancers among postmenopausal black women, but not Hispanic/Latinx women.”

Family history of breast cancer accounted for a small proportion of advanced breast cancer among premenopausal (8%) and postmenopausal (5%) women in the study. Previous studies have shown that women perceive a family history of breast cancer as the main risk factor for breast cancer, while others, such as being overweight or obese or breast density, are less important predictors. .

Kerlikowske adds that patients should be informed about the factors that most contribute to the development of advanced breast cancer and the primary prevention interventions that can modify these risk factors. Offering additional imaging with MRI or ultrasound to women at high risk for advanced cancer could also reduce the risk of being diagnosed with advanced cancer.