Randomized Trial of Text Messaging to Reduce Early Discontinuation of Adjuvant Aromatase Inhibitor Therapy in Women With Early-Stage Breast Cancer: SWOG S1105

PURPOSE

Nonadherence to aromatase inhibitors (AIs) for breast cancer is common and increases the risk of recurrence. Text messaging increases adherence to medications for chronic conditions.

METHODS

We conducted a randomized clinical trial of text messaging (TM) versus no text messaging (No-TM) at 40 sites in the United States. Eligible patients were postmenopausal women with early-stage breast cancer taking an AI for > 30 days with a planned duration of ≥ 36 months. Test messages were sent twice a week over 36 months. Content themes focused on overcoming barriers to medication adherence and 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 (AF), where AF was defined as urine AI metabolite assay results satisfying one of the following: < 10 ng/mL, undetectable, or no submitted specimen. A stratified log-rank test was conducted. Multiple sensitivity analyses were performed.

RESULTS

In total, 724 patients were registered between May 2012 and September 2013, among 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 TM and 55.4% for No-TM. The primary analysis showed no difference in time to AF by arm (3-year AF: 81.9% TM v 85.6% No-TM; HR, 0.89 [95% CI, 0.76 to 1.05]; P = .18). Multiple time to AF sensitivity analyses showed similar nonsignificant results. Three-year self-reported time to AF (10.4% v 10.3%; HR, 1.16 [95% CI, 0.69 to 1.98]; P = .57) and site-reported time to AF (21.9% v 18.9%; HR, 1.31 [95% CI, 0.86 to 2.01]; P = .21) also did not differ by arm.

CONCLUSION

To our knowledge, this was the first large, long-term, randomized trial of an intervention directed at improving AI adherence. We found high rates of AI AF. Twice-weekly text reminders did not improve adherence to AIs. Improving long-term adherence will likely require personalized and sustained behavioral interventions.

Randomized trial of text messaging (TM) to reduce early discontinuation of aromatase inhibitor (AI) therapy in women with breast cancer: SWOG S1105

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Background: Non-adherence to AI’s for breast cancer is common and increases risk of recurrence. Text messaging (TM) has been shown to increase adherence to medications for chronic conditions. We conducted a multicenter randomized trial to evaluate if TM reminders improve AI adherence. Methods: Patients taking an AI for ≥30 days and having ≥36 mos of planned therapy were eligible. Patients were randomly assigned 1:1 to receive either TM or NO-TM twice a week for 36 mos. Randomization was stratified by length of time on prior AI therapy ( < 12 (64%) vs. 12-24 mos (36%)) and AI class (anastrozole, letrozole, exemestane). Content themes of the 36 TMs focused on overcoming barriers to adherence. Patients were assessed for discontinuation of AIs every 3 mos for 36 mos. The primary outcome was time to non-adherence, where non-adherence was defined as urine AI metabolite assay results satisfying the following: < 10 [units], undetectable, or no submitted specimen. A stratified Log-rank test was conducted. Multiple sensitivity analyses were performed using Cox regression. Results: In total, 724 patients were registered between May, 2012 and September, 2013, among whom 696 (338/360 (93.9%) on TM and 338/364 (92.9%) on NO-TM) were eligible and adherent at baseline. Observed (time-independent) adherence at 36 mos was 55.4% for TM and 55.4% for NO-TM. The primary analysis showed no difference in time-to-adherence failure between patients on the TM and NO-TM arms (HR = 0.89, 95% CI:0.76,1.05 p = .18). An analysis of negative urine tests alone resulted in similar non-significant results. With missed appointments not counted as failures, time to self-reported discontinuation (89.6% vs. 89.7%; HR = 1.17, 95% CI:0.69-1.98, p = .57) and site reported discontinuation (78.1% vs. 81.1%; HR = 1.31, 95% CI:0.86-2.01, p = .21) were also similar between the 2 groups. Conclusions: As the first large long-term randomized trial of an intervention directed at improving AI adherence, we found high rates of AI discontinuation. Bi-weekly text reminders did not improve adherence to AIs compared to usual care. Improving long—term adherence will likely require sustained behavioral interventions and support. Clinical trial information: NCT01515800.