Abstract P5-09-13: Disparities in germline mutation testing: do Medi-Cal and uninsured patients with breast cancer receive genetic testing in a safety net setting?

Background: National Comprehensive Cancer Network guidelines recommend that women with breast cancer diagnosed at age ≤50 undergo cancer genetic risk assessment and that those age ≤45 undergo testing for hereditary breast and ovarian cancer (HBOC) syndromes such as BRCA. In prior studies of primarily commercially insured women, 30% of those ≤40 years of age received BRCA testing (Levy 2011), and 34% of those ≤50 years were referred for genetic assessment (Stuckey 2016). Our aim was to determine rates and predictors of genetic testing among publicly insured or uninsured women at a safety net medical center.

Methods: Women diagnosed with invasive breast cancer or ductal carcinoma in situ from 2010 through 2016 were identified from the institutional tumor registry of a Los Angeles County public hospital. Eligible for this analysis were those at high risk for HBOC syndromes as defined by 1) age ≤50 at diagnosis or 2) age ≤60 with triple negative breast cancer. Women were excluded if they received all of their cancer treatment at an outside institution. Medical records were reviewed to determine receipt of genetic testing and test results. Univariate logistic regression was used to evaluate associations between patient characteristics and receipt of testing.

Results: 307 women were included in the analysis. 92.5% (284) were age ≤50 and 54.7% (168) were age ≤45. The majority (72.1%) had Medi-Cal or Medicare and 26.1% were uninsured at diagnosis. The racial distribution was 63.8% Hispanic, 19.2% black, 11.1% Asian and 5.5% non-Hispanic white. Overall, 52.1% (160/307) underwent genetic testing and 13.1% (21/160) were found deleterious germline mutations (BRCA1=10, BRCA2=8, BRCA not specified=1, PALB2=1, TP53=1). Among women who underwent testing, 55.0% were tested for BRCA1/2 only and 36.8% received multigene panel testing; specific testing information was unavailable for the remainder. Age, race/ethnicity, and presence of metastatic disease at diagnosis were associated with differences in genetic testing rates, whereas insurance status and year of cancer diagnosis were not (Table 1).

Conclusions: In a safety net setting with mostly Medi-Cal-insured and uninsured patients, the overall rate of germline mutation testing in women with breast cancer (52.1%) was at least comparable to that in studies of commercially insured populations. Notably, testing rates in this population were significantly different when stratifying by age, race, and cancer stage. These findings highlight subgroups in this underserved population who warrant additional attention to assessment of their cancer genetic risk.

 Total (N=307)Number tested% testedP valueAge at diagnosis   P<0.001<30 years11872.7 30-39 years654569.2 40-49 years1819552.5 ≥50 years501224.0 Race/ethnicity   P=0.011Non-Hispanic white17635.3 Asian341955.9 Black592135.6 Hispanic19611458.2 Unknown100.0 Stage at diagnosis   P=0.007Non-metastatic28515554.4 Metastatic22522.7 Insurance   P=0.594Uninsured804758.8 Medi-Cal/Medicare*22311149.8 Private insurance2150.0 Unknown2150.0 Year of diagnosis   P=0.0982010421740.5 2011472348.9 2012462656.5 2013602948.3 2014392461.5 2015392153.8 2016342058.8 *1 patient had Medicare; the remainder had Medi-Cal

Citation Format: Pan K, Yan JE, Huynh KT, Peng KA, Ozao-Choy J, Dauphine C, Park S, Dickson PI. Disparities in germline mutation testing: do Medi-Cal and uninsured patients with breast cancer receive genetic testing in a safety net setting? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-09-13.

Ipilimumab for metastatic melanoma

Malignant melanoma is currently the fifth most common cancer in American men and the seventh most common in American women. Despite the advances made for early disease, the prognosis for metastatic melanoma is dismal, with an overall 5-year mortality rate of 90%. It is estimated that 8,000 Americans will die of melanoma in 2012. Recent advances in the understanding of the complex cellular interactions regulating cancer immunity have led to new strategies in the development of cancer immunotherapy. The discovery of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), a negative regulator of immune activity, has led to the development of a monoclonal antibody, ipilimumab, that can abrogate immune suppression. Ipilimumab is the first immunotherapy approved by the FDA for patients with advanced melanoma based on the overall survival benefit in a phase III setting. It represents a paradigm shift in melanoma management with its success promoting the evaluation of monoclonal antibodies targeted against a number of other regulatory checkpoints in patients with advanced melanoma.