Population-based screening programs


Screening family histories to identify patients with Hereditary Breast and Ovarian Cancer syndrome (HBOC) has recently been classified as a Tier 1 health application by the Centers for Disease Control (CDC). Tier 1 genomic applications are defined as those having a positive impact on public health based on available evidence. There are currently only three Tier 1 genomic screening activities, and those are: HBOC, Lynch syndrome, and familial hypercholesterolemia (the latter genetic test resulting from the pioneering work of Drs. Brown and Goldstein at UT Southwestern in defining the disease at the genetic level).

HBOC affects 1 in 500 individuals, and 1 in 40 of Ashkenazi Jewish descent. Because of its Tier 1 classification and the U.S. Preventative Services Task Force’s recommendation that all women over age 18 be screened for HBOC by obtaining a family history of cancer. Screening for HBOC should be done on a population basis and not individually.

As such, the UT Southwestern Cancer Genetics program is implementing population- based screening for family histories of cancer in its insured and underserved populations. To date, we have screened 117,759 mammogram patients in the underserved populations alone. These data serve as a baseline measure for us and others to use to improve screening as well as final outcomes. Of the unaffected women who underwent genetic testing through population screening for a family history of cancer, 4.5 percent were found to have a mutation. It is unlikely that these women would have been identified without this population-screening program. We’ve also learned that our underserved patients exhibit lower compliance with management recommendations compared to published data as well as compared to our smaller insured population. By improving compliance, we will increase the impact of cancer prevention in both populations.

Even though the CDC has given population screening for HBOC a Tier 1 classification, up until now little has been known about the effect of screening on cancer incidence in underserved populations. UT Southwestern is one of the first programs in the country to report on the effect of population screening with analysis from the program’s first 20 months of screening. We used a simple software model to calculate the long-term effect (30 years) of screening on breast and ovarian cancer incidence in patients with HBOC by assessing how often they chose to undergo surgical prevention measures. Using these data, we modeled the effect of compliance with prevention guidelines on cancer incidence over 30 years and predicted a 54 percent reduction in breast cancer and a 72 percent reduction in ovarian cancer in the insured population. However, only an 8.8 percent reduction in both breast and ovarian cancer was predicted for the underserved patients.

Our data indicate that underserved patients diagnosed with HBOC exhibit lower adherence to standard guidelines for cancer prevention compared to insured populations. However, even the insured population has much room to improve. Population screening for HBOC will be effective for cancer prevention only if more work can be done to remove barriers for underserved patients who have a genetic predisposition to cancer. We are working to increase education both of patients and their physicians to improve access to lifesaving surgeries and other prevention measures. These data provide the prototypical baseline for quantitative evaluation of efforts to improve adherence to NCCN guidelines for cancer prevention. They will be used at not only UT Southwestern but other cancer centers around the country as well.