Smartphone Psychotherapy Reduces Fear of Cancer Recurrence Among Breast Cancer Survivors: A Fully Decentralized Randomized Controlled Clinical Trial (J-SUPPORT 1703 Study)

PURPOSE Fear of cancer recurrence (FCR) is a common distressing condition. We investigated the efficacy of smartphone problem-solving therapy and behavioral activation applications in breast cancer survivors. METHODS This was a decentralized randomized trial. Participants were disease-free breast cancer survivors age 20-49 years who were randomly assigned to the smartphone-based intervention or waitlist control. Both groups received treatment as usual. The control group could access the smartphone apps during weeks 8-24. The intervention comprised smartphone problem-solving therapy and behavioral activation apps. The primary end point was the Concerns About Recurrence Scale at week 8. Secondary outcomes included the Fear of Cancer Recurrence Inventory-Short Form (FCRI-SF), the Hospital Anxiety and Depression Scale (HADS), the Short-form Supportive Care Needs Survey (SCNS-SF34), and the Posttraumatic Growth Inventory at weeks 8 and 24 (trial registration: UMIN-CTR: UMIN000031140). RESULTS The intervention group included 223 participants, and the control group included 224 participants. Primary outcome data were obtained for 444 participants, and 213 participants in the intervention arm completed the week 24 assessment. The intervention group had statistically greater improvements than controls at week 8 on the Concerns About Recurrence Scale (difference –1.39; 95% CI, –1.93 to –0.85; P < .001), FCRI-SF (difference –1.65; 95% CI, –2.41 to –0.89; P < .001), HADS depression (difference –0.49; 95% CI, –0.98 to 0; P < .05), and SCNS-SF34 psychological domain (difference –1.49; 95% CI, –2.67 to –0.32; P < .05). These scores at week 24 were not statistically significant compared with week 8 although the HADS depression score at week 24 was significantly reduced ( P = .03). CONCLUSION Novel smartphone psychotherapy offers a promising way to reduce FCR given the large number of survivors and a limited number of therapists to competently conduct psychotherapy.