Breast cancer chemoprevention: the saga of underuse continues

Patient and Provider Web-Based Decision Support for Breast Cancer Chemoprevention: A Randomized Controlled Trial

Significant underutilization of breast cancer chemoprevention remains, despite guidelines stating that physicians should recommend chemoprevention with antiestrogen therapy to high-risk women. We randomized women, ages 35 to 75 years, who met high-risk criteria for breast cancer, without a personal history of breast cancer or prior chemoprevention use, to standard educational materials alone or combined with a web-based decision aid. All healthcare providers, including primary care providers and breast specialists, were given access to a web-based decision support tool. The primary endpoint was chemoprevention uptake at 6 months. Secondary outcomes included decision antecedents (perceived breast cancer risk/worry, chemoprevention knowledge, self-efficacy) and decision quality (decision conflict, chemoprevention informed choice) based upon patient surveys administered at baseline, 1 and 6 months after randomization. Among 282 evaluable high-risk women enrolled from November 2016 to March 2020, mean age was 57 years (SD, 9.9) and mean 5-year invasive breast cancer risk was 2.98% (SD, 1.42). There was no significant difference in chemoprevention uptake at 6 months between the intervention and control groups (2.1% vs. 3.5%). Comparing the intervention and control arms at 1 month, there were significant differences among high-risk women in accurate breast cancer risk perceptions (56% vs. 39%, P = 0.017), adequate chemoprevention knowledge (49% vs. 27%, P < 0.001), mean decision conflict (34.0 vs. 47.0, P < 0.001), and informed choice (41% vs. 23%, P = 0.003). These differences were no longer significant at 6 months. Although our decision support tools did not result in a significant increase in chemoprevention uptake, we did observe improvements in decision antecedents and decision quality measures.

PREVENTION RELEVANCE

In this randomized controlled trial of decision support for 300 high-risk women and 50 healthcare providers, we did not observe a significant increase in chemoprevention uptake, which remained low at under 5%. However, these decision support tools may increase knowledge and informed choice about breast cancer chemoprevention.

Implementation of Risk-reducing Strategies for Breast Cancer is Long Overdue

Despite strong evidence that it is efficacious, chemoprevention has been underused in eligible women. Reasons offered not to adopt and initiate strategies to reduce the risk of breast cancer include the fear of adverse effects, medication costs, lack of reasonably accurate and feasible methods for assessing an individual's personal risk, and lack of established risk thresholds that maximize benefit and minimize harms. The article by Macdonald and colleagues remind us that the problem of lack of uptake of risk-reducing medications for breast cancer remains a worldwide clinical challenge despite endorsements from national and international organizations that recommend the use of risk-reducing medications for breast cancer with level I evidence. Several strategies are suggested to improve uptake and utilization of safe and effective chemoprevention medications with high therapeutic indices.See related article by Macdonald et al., p. 131.

Breast cancer risk reduction: Notable achievements and remaining challenges

Millions of women in the United States are at increased risk of breast cancer. Multiple prospective, randomized clinical trials have demonstrated both the efficacy and safety of selective estrogen receptor modulators and aromatase inhibitors in reducing substantially the risk of invasive breast cancer in women at increased risk. Published tables are available to aid clinicians in shared decision-making regarding drug interventions with their patients who are at increased risk of breast cancer. Both professional and governmental agencies have advised that these interventions should be offered to women at increased risk of breast cancer. Doing so would reduce breast cancer morbidity substantially.

Use of raloxifene and tamoxifen by breast cancer risk level in a Medicare-eligible cohort

BACKGROUND

Raloxifene and tamoxifen are Food and Drug Administration-approved for breast cancer risk reduction; in 2013, the US Preventive Services Task Force recommended these drugs for breast cancer risk reduction in high-risk women. Information on the use of raloxifene and tamoxifen for breast cancer risk reduction in the general population indicates that the risk is believed to be low; however, there is little literature.

OBJECTIVE

The purpose of this study was to assess the use of breast cancer risk reduction medications by breast cancer risk level in an older cohort of women.

STUDY DESIGN

Women who were enrolled in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial were assessed for the use of raloxifene, tamoxifen, and other medications. The data sources for use of the drugs were a mailed medication use questionnaire in 2013 and linked Medicare Part D claims files from 2010-2014. Estimated breast cancer risk within 5 years was assessed with the use of the modified Gail model and self-reported breast cancer risk factors; comorbidities were assessed through a questionnaire.

RESULTS

A total of 22,235 women completed the medication use questionnaire; of these, 13,640 women (61%) had linked Part D data. In 2013, 45% of the women were 65-74 years old, and 55% of the women were 75-84 years old. From the medication use questionnaire, raloxifene use (past month) was 1.8%, 2.5%, and 4.0% for women with breast cancer risk within 5 years of <1.66%, 1.66-3.0%, and ≥3%, respectively (probability value trend, <.0001). From Part D, for any use during the period among women with coverage, raloxifene rates were 3.3%, 4.0%, and 6.6% for the 3 categories for breast cancer risk within 5 years (probability value trend, <.0001); use was 7.4% and 3.3% in women with and without osteoporosis, respectively. Raloxifene use significantly decreased from 2010-2014, and specifically from 2012-2014, both for all women and for women with breast cancer risk within 5 years of ≥3%. Tamoxifen use from Part D was 0.36%, 0.45%, and 0.85% for the 3 categories for breast cancer risk within 5 years (probability value trend, .009).

CONCLUSION

Raloxifene use was low overall but increased modestly with breast cancer risk, and usage decreased from 2010-2014. Tamoxifen use was very low.

Breast cancer chemoprevention pharmacogenomics: Deep sequencing and functional genomics of the ZNF423 and CTSO genes

Our previous GWAS using samples from the NSABP P-1 and P-2 selective estrogen receptor modulator (SERM) breast cancer prevention trials identified SNPs in ZNF423 and near CTSO that were associated with breast cancer risk during SERM chemoprevention. We have now performed Next Generation DNA sequencing to identify additional SNPs that might contribute to breast cancer risk and to extend our observation that SNPs located hundreds of bp from estrogen response elements (EREs) can alter estrogen receptor alpha (ERα) binding in a SERM-dependent fashion. Our study utilized a nested case-control cohort selected from patients enrolled in the original GWAS, with 199 cases who developed breast cancer during SERM therapy and 201 matched controls who did not. We resequenced approximately 500 kb across both ZNF423 and CTSO, followed by functional genomic studies. We identified 4079 SNPs across ZNF423 and 3876 across CTSO, with 9 SNPs in ZNF423 and 12 in CTSO with p < 1E-02 that were within 500 bp of an ERE motif. The rs746157 (p = 8.44E-04) and rs12918288 SNPs (p = 3.43E-03) in intron 5 of ZNF423, were in linkage equilibrium and were associated with alterations in ER-binding to an ERE motif distant from these SNPs. We also studied all nonsynonymous SNPs in both genes and observed that one nsSNP in ZNF423 displayed decreased protein expression. In conclusion, we identified additional functional SNPs in ZNF423 that were associated with SNP and SERM-dependent alternations in ER binding and transcriptional regulation for an ERE at a distance from the SNPs, thus providing novel insight into mechanisms of SERM effect.

The Burdens and Uncertainties of Doing What One Should Do

Despite FDA approval of drugs to reduce the risk of breast cancer in women at increased risk, uptake of these drugs has been poor despite the publication of numerous studies that demonstrate both their effectives and safety. National organizations have made recommendations for their use, but both physicians and their patients do not fully understand either breast cancer risk factors or risk assessment or the indications for using risk-reducing agents. Histologically predisposing conditions, such as ductal or lobular atypia and lobular carcinoma in situ, impart particularly high risks of developing subsequent invasive breast cancer. Resources should be committed to both provider and patient education to reduce the risk of breast cancer in women who are at increased risk. Cancer Prev Res; 10(8); 431-3. ©2017 AACR.

An exploratory study of patients' views about being at high-risk for breast cancer and risk management beliefs and intentions, before and after risk counselling: Preliminary evidence of the influence of beliefs on post-counselling prevention intentions

OBJECTIVES

1) To describe how women at high-risk for breast cancer (BC) perceive their at-risk status and the options available to manage this risk, before and after risk counselling; 2) to explore the contributions of pre-counselling demographic, clinical, cognitive and emotional factors to post-counselling risk management intentions.

METHODS

58 of 173 eligible patients (34%) enrolled and were asked to fill surveys including measures of 1) subjective risk, 2) illness (being at high-risk for BC) and 3) treatment (surveillance, lifestyle modifications, and chemoprevention) cognitions, 4) BC fear and 5) future risk management intentions, prior to and 3 months after risk consultation.

RESULTS

48 of 58 participants (83%) completed both surveys. Beliefs and emotions about their condition and its management were stable over time. Surveillance and lifestyle were associated with stronger intentions, higher perceived need, and lower concerns than chemoprevention (all ps <0.001). The strongest predictors of intentions strengths were the women's beliefs about the risk reduction methods, especially for lifestyle and chemoprevention (all ps <0.01).

CONCLUSIONS

The findings emphasize the importance of patients' beliefs in risk management decisions.

PRACTICAL IMPLICATIONS

Patients' treatment beliefs appear to influence their choice of BC risk reduction strategies and should be discussed during risk reduction consultations.

Breast Density and Benign Breast Disease: Risk Assessment to Identify Women at High Risk of Breast Cancer

PURPOSE

Women with proliferative breast lesions are candidates for primary prevention, but few risk models incorporate benign findings to assess breast cancer risk. We incorporated benign breast disease (BBD) diagnoses into the Breast Cancer Surveillance Consortium (BCSC) risk model, the only breast cancer risk assessment tool that uses breast density.

METHODS

We developed and validated a competing-risk model using 2000 to 2010 SEER data for breast cancer incidence and 2010 vital statistics to adjust for the competing risk of death. We used Cox proportional hazards regression to estimate the relative hazards for age, race/ethnicity, family history of breast cancer, history of breast biopsy, BBD diagnoses, and breast density in the BCSC.

RESULTS

We included 1,135,977 women age 35 to 74 years undergoing mammography with no history of breast cancer; 17% of the women had a prior breast biopsy. During a mean follow-up of 6.9 years, 17,908 women were diagnosed with invasive breast cancer. The BCSC BBD model slightly overpredicted risk (expected-to-observed ratio, 1.04; 95% CI, 1.03 to 1.06) and had modest discriminatory accuracy (area under the receiver operator characteristic curve, 0.665). Among women with proliferative findings, adding BBD to the model increased the proportion of women with an estimated 5-year risk of 3% or higher from 9.3% to 27.8% (P<.001).

CONCLUSION

The BCSC BBD model accurately estimates women's risk for breast cancer using breast density and BBD diagnoses. Greater numbers of high-risk women eligible for primary prevention after BBD diagnosis are identified using the BCSC BBD model.

JNCI and cancer prevention

The Journal of the National Cancer Institute (JNCI), with its broad coverage of bench research, epidemiologic studies, and clinical trials, has a long history of publishing practice-changing studies in cancer prevention and public health. These include studies of tobacco cessation, chemoprevention, and nutrition. The landmark Breast Cancer Prevention Trial (BCPT)-the first large trial to prove efficacy of a preventive medication for a major malignancy-was published in the Journal, as were key ancillary papers to the BCPT. Even when JNCI was not the publication venue for the main trial outcomes, conceptual and design discussions leading to the trial as well as critical follow-up analyses based on trial data from the Prostate Cancer Prevention Trial (PCPT) and the Selenium and Vitamin E Chemoprevention Trial (SELECT) were published in the Journal. The Journal has also published important evidence on very charged topics, such as the purported link between abortion and breast cancer risk. In summary, JNCI has been at the forefront of numerous major publications related to cancer prevention.