Pilot Comparison of N-of-1 Trials of Light Therapy

This study compares the effect of two N-of-1 trials on study compliance with an N-of-1 protocol and on satisfaction with participation in an N-of-1 trial. Using within-person analyses, the study also compares the effect of different types of light therapy on mood, fatigue, sleep, physical activity, and side effects within a mild to moderately depressed cancer survivor population. Ten participants will be randomized to the bright white versus dim red light therapy N-of-1 trial, while the remaining 5 participants will be randomized to a dim white versus dim red light comparator N-of-1 trial.

Fatigue or low energy levels, trouble sleeping and feeling down are symptoms that represent some of the most important concerns in cancer survivors, across a range of cancer types. Despite the impact of these symptoms on quality of life, previous studies have shown that few cancer survivors are receiving adequate treatment for these symptoms. Light therapy involves the use of a light box (a box that lights up) in close proximity for a specified amount of time each day. There can be big differences in the way light therapy affects individual patients. Patients can learn whether this therapy is helpful to them by engaging in an N-of-1 trial. An N-of-1 trial is an experiment conducted with one individual (N refers to "number of individuals in the trial"). In an N-of-1 trial of light therapy, a patient can try light therapy to learn whether it is beneficial to them. All participants will receive two light boxes. The boxes will be labeled "A" and "B." Each light box will emit a different intensity of light. An app will send reminder notifications to participants' smartphones each morning to remind them which light box they should be using, depending on the week. They will be asked to use Box A or Box B each morning for 30 minutes per day for 12 weeks The purpose of this study is to empower cancer survivors with symptoms of fatigue, trouble sleeping or who are feeling down to learn whether light therapy is helpful for them.

This study aims to assess the feasibility of conducting a randomized trial comparing two N-of-1 trials of light therapy in cancer survivors with depressive symptoms. In the first N-of-1 trial, participants will compare bright white light with dim red light therapy. In the second N-of-1 trial, participants will compare dim white light with dim red light. Participants will be randomized in a 2:1 ratio to either the N-of-1 bright white light vs dim red light experimental arm (N=20) or to a dim white vs dim red light therapy active comparator (N=10).

A balanced sequence (ABBA) over a 12 week period of bright white light and dim red light; alternating bright white and dim red light every 3 weeks. Subjects will receive 2 Litebook® Advantage lightboxes - 1 bright white and 1 dim red. Information such as mood, fatigue, sleep and light therapy side effects will be self-reported using a smartphone diary; physical activity and sleep will also be reported using a Fitbit Flex2 TM. Data visualization at 12 weeks.

A balanced sequence (ABBA) over a 12 week period of dim white light and dim red light; alternating dim white and dim red light every 3 weeks. Subjects will receive 2 Litebook® Advantage lightboxes - 1 dim white and 1 dim red. Information such as mood, fatigue, sleep and light therapy side effects will be self-reported using a smartphone diary; physical activity and sleep will also be reported using a Fitbit Flex2 TM. Data visualization at 12 weeks.

Standard system light therapy device used in an investigation to assess the feasibility of conducting a randomized trial design. The lightbox produces different wavelengths of the light identical to the peak wavelengths of the sun - bright white, dim white and red light.

The proportion of participants randomized to the N-of-1 trial group who are compliant with the N-of-1 trial protocol

The proportion of participants randomized to the N-of-1 trial who are satisfied with the N-of-1 trial protocol

At the single-patient level in the bright white light experimental arm, effect of bright light versus dim white light on mood as measured by a daily visual analog scale.

At the single-patient level in the bright white light experimental arm, effect of bright light versus dim white light on fatigue as measured by a daily visual analog scale.

At the single-patient level in the bright white light experimental arm, effect of bright light versus dim white light on days with perceived side-effects as measured by a smart phone daily diary.

At the single-patient level in the bright white light experimental arm, effect of bright light versus dim white light on physical activity as measured by a Fitbit.

Within the bright white light experimental arm, the proportion who preferred to continue bright white light after the conclusion of the N-of-1 trial.

Inclusion Criteria: History of cancer (not including basal cell or squamous cell carcinoma, or carcinoma in situ) Current mild to moderate severity depressive symptoms (PHQ-8 score 5 to 19) iPhone user Exclusion Criteria: Has not completed primary cancer treatment including initial chemotherapy, surgical resection, or radiation therapy Non-English speaking Severe depression (PHQ-8 score >=20) or active suicidal ideations Other severe mental illness that would preclude participation in a study that requires extensive self-monitoring, including depression with psychotic features, other psychotic disorder, bipolar disorder, severe personality disorder <6 months life expectancy due to cancer or other severe medical illness Other severe medical illness that would preclude ability to do daily self-tracking Unavailable for follow-up over the course of the 3 month trial