Prediction of Cancer Prevention: From Mammogram Screening to Identification of BRCA1/ 2 Mutation Carriers in Underserved Populations

Abstract

Background

The US Preventative Service Task Force recommends that physicians perform a genetic risk assessment to identify women at risk for BRCA1/ 2 mutations associated with hereditary breast and ovarian cancer (HBOC) syndrome. However, outcomes data after a diagnosis of HBOC syndrome especially in diverse populations, are minimal. Here we asked if genetic screening of high-risk underserved women identified in the mammogram population reduces cancer incidence.

Methods

We evaluated 61,924 underserved women at screening mammography for family histories suggestive of HBOC syndrome over the course of 21 months. Data were collected retrospectively from patients at two safety net hospitals through chart review. A computer model was used to calculate the long-term effect of this screening on cancer incidence by assessing both the mutation detection rate and the completion of prophylactic surgeries in BRCA1/ 2 mutation carriers.

Findings

We identified 20 of the 85 (23.5%) expected BRCA1/ 2 mutation carriers in the underserved population. The frequencies of prophylactic mastectomies and oophorectomies in the mutation carriers were 25% and 40%, respectively. Using these data, our model predicted only an 8.8% reduction in both breast and ovarian cancer in the underserved patients. This contrasts with a 57% reduction in breast cancer and 51% reduction in ovarian cancer in an insured reference population. Our data indicate that underserved patients with HBOC syndrome are difficult to identify and when identified are limited in their ability to adhere to NCCN guidelines for cancer prevention.

Interpretation

Screening for women at risk for HBOC syndrome in mammogram populations will only prevent cancers if we can increase compliance with management guidelines. This study provides prototypic baseline data for step-wise analysis of the efficacy of the use of family history analysis in the mammography setting for detection and management of HBOC syndrome.

Highlights

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  We report outcomes from screening underserved populations at mammography for risk of having a hereditary cancer syndrome.

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  Despite the screening program, discovery of BRCA mutations and prophylactic surgery rates were low in the underserved.

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  A prototype model used the study's outcomes to predict population cancer reduction and identify how to improve prevention.

This study evaluated 96,055 individuals at mammography for a family history of cancer to identify BRCA mutation carriers who have a genetic predisposition to breast and ovarian cancer.

The level of success in identification of high risk individuals and completion of cancer prevention activities was used to quantify cancer prevention as a result of our screening program.

We observed suboptimal outcomes, especially in the underserved populations, where screening for high risk individuals did not reduce cancer incidence. This study's model can be used for screening programs to find high risk patients and identify ways to improve outcomes for these patients.