Study Identifies Barriers to Endocrine Therapy Adherence in Breast Cancer Survivors


In this study, researchers found that 59% of the participants reported at least 1 barrier to endocrine therapy adherence, though over half reported that taking endocrine therapy was a joint decision between themselves and their doctor.

In a study published in Psycho-Oncology, researchers were able to characterize barriers to endocrine therapy by 3 distinct factors, including habit-formation, perceptions of low risk and benefit tradeoffs, and inadequate resources, and strongly correlated with sociodemographic attributes.1

Additionally, the data suggested that barriers to endocrine therapy adherence seem inadequately addressed for younger, black, and publicly insured breast cancer survivors. 

“As doctors and researchers continue to develop strategies to support women with a history of breast cancer, it will be important to develop patient-centered, multi-faceted strategies to improve (endocrine therapy) adherence across the full breast cancer population,” the authors wrote. 

Using 1,231 women included in the Carolina Breast Cancer Study, which oversampled black and young women, researchers found that 59% of the women reported at least one barrier to endocrine therapy adherence. They were able to identify 3 latent factors, which were defined as:

  • Habit: challenges developing medication-taking behavior

  • Tradeoffs: high perceived side effect burden and medication safety concerns

  • Resource barriers: challenges related to cost or accessibility

Over half (52.2%) of the patients reported that taking endocrine therapy was a joint decision between themselves and their doctor, while 22.3% felt that their doctor led the decision, 17.2% felt that they led the decision, and 6.9% reported no discussion of endocrine therapy before being prescribed medication.

Women were most likely to say they miss pills because they “just forget” (27.2% reported “sometimes” or “often”) or because they forget their pills when they are away from home (22.7%). Overall, 31.3% of the women identified at least 1 item in the habit factor that affected adherence. Further, a sizeable percentage of women also reported challenges related to risk/benefit tradeoffs of endocrine therapy, with 27.6% endorsing at least one tradeoff item. The least common reason for endocrine therapy nonadherence were resource barriers, as only 12.1% of women responded that either medication cost or the refilling of prescriptions was a barrier, though the prevalence of this barrier varied across the groups.

Older age, defined as those older than 50 years of age, was correlated with less reporting of habit (adjusted risk ratio, 0.54; 95% CI, 0.43-0.69) and resource barriers (adjusted risk ratio, 0.66; 95% CI, 0.43-0.997), but was not associated with tradeoff barriers. Moreover, Medicaid-insured women were more likely than those who were privately-insured to report tradeoff (adjusted risk ratio, 1.53; 95% CI, 1.10-2.13) or resource barriers (adjusted risk ratio, 4.43; 95% CI, 2.49-6.57). Black race was also associated with increased reporting of habit (adjusted risk ratio, 1.29; 95% CI, 1.09-1.53), tradeoffs (adjusted risk ratio, 1.32; 95% CI, 1.09-1.60), and resources (adjusted risk ratio, 1.65; 95% CI, 1.18-2.30).

“Endocrine therapy can offer a big benefit for breast cancer survivors, but many of the strategies we use to help women who are struggling with medication adherence are only designed to address one barrier at a time,” lead author Jennifer Spencer, PhD, of the University of North Carolina at Chapel Hill, said in a press release.2 “Our study finds that there are at least 3 distinct kinds of barriers that women might experience when taking endocrine therapy – suggesting that intervention strategies that can help address multiple barriers at once might be more effective, especially for black women.” 

According to the study, endocrine therapy medication taken for 5 to 10 years after completing primary treatments can reduce the risk of cancer recurrence by up to 50%. However, non-adherence rates are estimated to range from 20% to 50%, even among those initiate endocrine therapy. 


1. Spencer JC, Reeve BB, Troester MA, Wheeler SB. Factors Associated with Endocrine Therapy Non-Adherence in Breast Cancer Survivors. Psycho-Oncology. doi:10.1002/pon.5289. 

2. Certain Factors Linked with Discontinuing Breast Cancer Therapy [news release]. Published February 19, 2020. Accessed February 21, 2020. 

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