Text-Messaging Interventions Did Not Reduce Aromatase Inhibitor Adherence Failure

This study found that a biweekly unidirectional text-messaging intervention did not reduce aromatase inhibitor adherence failure in women with breast cancer.

A randomized clinical trial published in the Journal of Clinical Oncology indicated that a biweekly unidirectional text-messaging intervention did not reduce aromatase inhibitor (AI) adherence failure in women with breast cancer, regardless of the definition of the metric.1

Given the implications of this trial, researchers suggested that improving long-term adherence will likely require sustained and personalized behavioral interventions, symptom management, and support.

“This trial has design implications for other medication adherence interventions that are often of short duration,” the authors wrote. “Future trials may focus on enhancing two-way communication to increase early interventions to prevent discontinuation.” 

The trial evaluated text messaging versus no text messaging at 40 sites across the US. Eligible patients were postmenopausal women with early-stage breast cancer taking an AI for >30 days with a planned duration of ≥36 months.

Messages were sent twice a week over 36 months, and the content themes focused on overcoming barriers to medication adherence. Moreover, the texts included cues to action, statements related to medication efficacy, and reinforcements of the recommendation to take AIs. 

Both groups were assessed every 3 months. The primary outcome was time to adherence failure, defined as urine AI metabolite assay results which were classified as either <10 ng/mL, undetectable, or submitted specimen. 

Overall, 724 patients were registered between May 2012 and September 2013, of whom 702 patients (348 in the text-messaging arm and 354 in the no-text-messaging arm) were eligible at baseline. Observed adherence at 36 months was 55.5% for those receiving the text messages and 55.4% for those who were not. 

Even further, the primary analysis demonstrated no difference in time to adherence failure by arm (3-year adherence failure, 81.9% for text-messaging vs 85.6% for no-text-messaging; HR, 0.89; 95% CI, 0.76-1.05; P = 0.18). Multiple time to adherence failure sensitivity analyses saw similar nonsignificant results. Additionally, 3-year self-reported time to adherence failure (10.4% vs 10.3%, respectively; HR, 1.16; 95% CI, 0.69-1.98; P = 0.57) and site-reported time to adherence failure (21.9% vs 18.9%; HR, 1.31; 95% CI, 0.86-2.01; P = 0.21) did not differ by arm. 

“Short-term adherence does not likely translate to improved outcomes in breast cancer, and no prior study has evaluated the long-term effects of an intervention,” the authors wrote. “Furthermore, the simple receipt of text messages represents a passive experience for patients, and the messages themselves may become repetitive. Thus, the unidirectional text-messaging intervention used in this study that did not actively engage the patient may have been insufficient to produce behavioral change.”

In an editorial written by Elizabeth J. Cathcart-Rake, MD, and Kathryn J. Ruddy, MPH, MD, it was indicated that regardless of the negative results presented in this study, further investigations into how technological interventions might improve adherence to endocrine therapy should still be pursued.2 Additionally, the editorial authors suggested that future studies may do well to focus on premenopausal breast cancer survivors, as young women are more likely to be non-adherent than older women and also tend to be more reliant on mobile devices and receptive to technology.

“Because more than a million women around the world are diagnosed with hormonally sensitive breast cancer each year, it is important that we continue to study ways to improve adherence to endocrine therapy, taking into account patient preferences and individualized barriers to adherence and tailoring technological solutions to these concerns and values,” the editorial authors wrote.


1. Hershman DL, Unger JM, Hillyer GC, et al. Randomized Trial of Text Messaging to Reduce Early Discontinuation of Adjuvant Aromatase Inhibitor Therapy in Women With Early-Stage Breast Cancer: SWOG S1105. Journal of Clinical Oncology. doi:10.1200/JCO.19.02699.

2. Cathcart-Rake EJ, Ruddy KJ. Smart Technology and Endocrine Therapy Adherence. Journal of Clinical Oncology. doi:10.1200/JCO.20.0078.