Chemoprevention for breast cancer: overcoming barriers to treatment

Screening High-Risk Women Veterans for Breast Cancer

BACKGROUND

Within the US Department of Veterans Affairs (VA), breast cancer prevalence has more than tripled from 1995 to 2012. Women veterans may be at an increased breast cancer risk based on service-related exposures and posttraumatic stress disorder (PTSD).

METHODS

Women veterans aged ≥ 35 years with no personal history of breast cancer were enrolled at 2 urban VA medical centers. We surveyed women veterans for 5-year and lifetime risks of invasive breast cancer using the Gail Breast Cancer Risk Assessment Tool (BCRAT). Data regarding demographics, PTSD status, eligibility for chemoprevention, and genetic counseling were also collected. Descriptive statistics were used to determine results.

RESULTS

A total of 99 women veterans participated, of which 60% were Black. In total, 35% were high risk with a 5-year BCRAT > 1.66%. Breast biopsies had been performed in 22% of our entire population; 57% had a family history positive for breast cancer. Comparatively, in our high-risk Black population, 33% had breast biopsies and 94% had a family history. High-risk patients were referred for chemoprevention; 5 accepted and 13 were referred for genetic counseling. PTSD was present in 31% of the high-risk subgroup.

CONCLUSIONS

A high percentage of Black patients participated in this pilot study, which also showed an above average rate of PTSD among women veterans who are at high risk for developing breast cancer. Historically, breast cancer rates among Black women are lower than those found in the general population. High participation among Black women veterans in this pilot study uncovered the potential for further study of this population, which is otherwise underrepresented in research. Limitations included a small sample size, exclusively urban population, and self-selection for screening. Future directions include the evaluation of genetic and molecular mutations in high risk Black women veterans, possibly even a role for PTSD epigenetic changes.

Management of intracranial melanomas in the era of precision medicine

Melanoma is the most lethal of skin cancers, in part because of its proclivity for rapid and distant metastasis. It is also potentially the most neurotropic cancer in terms of probability of CNS metastasis from the primary lesion. Despite surgical resection and radiotherapy, prognosis remains guarded for patients with brain metastases. Over the past five years, a new domain of personalized therapy has emerged for advanced melanoma patients with the introduction of BRAF and other MAP kinase pathway inhibitors, immunotherapy, and combinatory therapeutic strategies. By targeting critical cellular signaling pathways and unleashing the adaptive immune response against tumor antigens, a subset of melanoma patients have demonstrated remarkable responses to these treatments. Over time, acquired resistance to these modalities inexorably develops, providing new challenges to overcome. We review the rapidly evolving terrain for intracranial melanoma treatment, address likely and potential mechanisms of resistance, as well as evaluate promising future therapeutic approaches currently under clinical investigation.

Chemoprevention Uptake among Women with Atypical Hyperplasia and Lobular and Ductal Carcinoma In Situ

Women with atypical hyperplasia and lobular or ductal carcinoma in situ (LCIS/DCIS) are at increased risk of developing invasive breast cancer. Chemoprevention with selective estrogen receptor modulators or aromatase inhibitors can reduce breast cancer risk; however, uptake is estimated to be less than 15% in these populations. We sought to determine which factors are associated with chemoprevention uptake in a population of women with atypical hyperplasia, LCIS, and DCIS. Women diagnosed with atypical hyperplasia/LCIS/DCIS between 2007 and 2015 without a history of invasive breast cancer were identified (N = 1,719). A subset of women (n = 73) completed questionnaires on breast cancer and chemoprevention knowledge, risk perception, and behavioral intentions. Descriptive statistics were generated and univariate and multivariable log-binomial regression were used to estimate the association between sociodemographic and clinical factors and chemoprevention uptake. In our sample, 29.3% had atypical hyperplasia, 23.3% had LCIS, and 47.4% had DCIS; 29.4% used chemoprevention. Compared with women with atypical hyperplasia, LCIS [RR, 1.43; 95% confidence interval (CI), 1.16-1.76] and DCIS (RR, 1.54; 95% CI, 1.28-1.86) were significantly associated with chemoprevention uptake, as was medical oncology referral (RR, 5.79; 95% CI, 4.80-6.98). Younger women were less likely to take chemoprevention (RR, 0.61; 95% CI, 0.42-0.87), and there was a trend toward increased uptake in Hispanic compared with non-Hispanic white women. The survey data revealed a strong interest in learning about chemoprevention, but there were misperceptions in personal breast cancer risk and side effects of chemoprevention. Improving communication about breast cancer risk and chemoprevention may allow clinicians to facilitate informed decision-making about preventative therapy. Cancer Prev Res; 10(8); 434-41. ©2017 AACR.

Physician and Patient Barriers to Breast Cancer Preventive Therapy

The uptake of selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs) for the primary prevention of breast cancer is low, despite their proven efficacy in several randomized clinical trials. This review summarizes the latest data on physicians' and women's barriers to breast cancer preventive therapy. Physicians' challenges include: identifying suitable candidates for preventive therapy, inadequate training and confidence in risk assessment and counselling, insufficient knowledge of risk-reducing medications, and lack of time. High-risk women fear medication side effects, and they often weigh experiences of others more heavily than statistical probabilities to guide their decision-making. Despite decision aid interventions to help women make an informed decision, acceptance of preventive therapy will remain low until: risk/benefit profiles are more favorable, physicians are better educated and skilled in having these discussions, and suitable biomarkers to monitor drug efficacy and better clinical risk prediction models to assess true individual risk are available.

Decision making in the context of breast cancer chemoprevention: patient perceptions and the meaning of risk

Chemoprevention with selective estrogen receptor modulators (SERMs) is considered one of the most promising risk reduction options to date in the United States. Tamoxifen and raloxifene are both approved by the U.S. Food and Drug Administration (FDA) for breast cancer risk reduction. However, despite endorsement from the American Society for Clinical Oncology and the National Comprehensive Cancer Network, uptake remains low. Decision aids have been successful in improving women's understanding and knowledge about the risk-benefit trade-offs in decision making regarding SERMs. However, increased knowledge does not lead to increased uptake of chemoprevention for the purpose of reducing breast cancer risk; instead, women become more reluctant to take medication that is itself associated with risks. Reasons for this include a lack of awareness that SERMs are effective in reducing breast cancer risk, an unwillingness to increase the risk of other disease, reluctance to take a daily medication, and the perception of tamoxifen as a "cancer drug." In studies on hypothetical decision making in the context of chemoprevention women indicate greater willingness to take a SERM when they are determined to be at risk. These findings suggest a differential understanding of what risk means among the general public, health professionals, and researchers. Feeling at risk is related to bodily signs and symptoms and not to population-derived probabilities. Such differential understanding may in part explain women's perception of the low efficacy of SERMs and their decision making regarding SERM use.