“Benign breast disease is a key risk factor for breast cancer risk prediction,” commented presenting investigator, of the Hospital del Mar Medical Research Institute in Barcelona. “Those women who have had a benign breast disease diagnosis have an increased risk that lasts for at least 20 years.”
To assess the combined influence of various attributes of benign breast disease, the investigators studied 629,087 women, aged 50-69 years, in Spain who underwent population-based mammographic breast cancer screening during 1994-2015 and did not have breast cancer at their prevalent (first) screen. The mean follow-up was 7.8 years.
Results showed that breast cancer risk was about three times higher for women with benign breast disease that was proliferative or that was detected on an incident screen, relative to peers with no benign breast disease. When combinations of factors were considered, breast cancer risk was most elevated – more than four times higher – for women with proliferative benign breast disease with atypia detected on an incident screen.
“We believe that these findings should be considered when discussing risk-based personalized screening strategies because these differences between prevalent and incident screens might be important if we want to personalize the screening, whether it’s the first time a woman comes to the screening program or a subsequent screen,” Dr. Román said.
The study’s large size and population-based design, likely permitting capture of most biopsy results, are strengths,, of the University of Michigan, Ann Arbor, commented in an interview.
But its observational, retrospective nature opens the study up to biases, such as uncertainty as to how many women were symptomatic at the time of their mammogram and the likelihood of heightened monitoring after a biopsy showing hyperplasia, Dr. Pearlman cautioned.
“Moreover, the relative risk in this study for proliferative benign breast disease without atypia is substantially higher than prior observations of this group. This discrepancy was not discussed by the authors,” Dr. Pearlman said.
At present, women’s risk of breast cancer is predicted using well-validated models that include the question of prior breast biopsies, such as the, the Tyrer-Cuzick model ( ), and the , Dr. Pearlman noted.
“This study, without further validation within a model, would not change risk assessment,” he said, disagreeing with the investigators’ conclusions. “What I would say is that further study to determine how to use this observation to decide if any change in screening or management should occur would be more appropriate.”
The 629,087 women studied underwent 2,327,384 screens, Dr. Román reported. In total, screening detected 9,184 cases of benign breast disease and 9,431 breast cancers.
Breast cancer was diagnosed in 2.4% and 3.0% of women with benign breast disease detected on prevalent and incident screens, respectively, compared with 1.5% of women without any benign breast disease detected.
Elevation of breast cancer risk varied across benign breast disease subtype. Relative to peers without any benign disease, risk was significantly elevated for women with nonproliferative disease (adjusted hazard ratio, 1.95), proliferative disease without atypia (aHR, 3.19), and proliferative disease with atypia (aHR, 3.82).
Similarly, elevation of risk varied depending on the screening at which the benign disease was detected. Risk was significantly elevated when the disease was found at prevalent screens (aHR, 1.87) and more so when it was found at incident screens (aHR, 2.67).
There was no significant interaction of these two factors (P = .83). However, when combinations were considered, risk was highest for women with proliferative benign breast disease with atypia detected on incident screens (aHR, 4.35) or prevalent screens (aHR, 3.35), and women with proliferative benign breast disease without atypia detected on incident screens (aHR, 3.83).
This study was supported by grants from Instituto de Salud Carlos III FEDER and by the Research Network on Health Services in Chronic Diseases. Dr. Román and Dr. Pearlman disclosed no conflicts of interest.
SOURCE: Román M et al. EBCC-12 Virtual Conference, .