The “PC-LIGHT” Study

Inclusion Criteria:

Have been diagnosed with clinical localized prostate cancer,
Are about to begin external beam radiation therapy (RT) for prostate cancer,
Are 18 years of age or older,
Are able to speak or read English,
Have internet access.

Exclusion Criteria:

History of light therapy use (e.g. systematic light exposure),
Active infection
History of chronic fatigue disorders
Confounding underlying medical illnesses such as significant pre-existing anemia (Hb<10 gm/dl)
Diagnosed or suspected psychiatric or medical condition that might contribute to fatigue (other than those caused by the cancer or its treatment)
Hypothyroidism or documented history of hypothyroidism on thyroid replacement hormone within <3 months of initiating RT
History of bipolar disorder or mania
History of seasonal affective disorder
Diagnosed sleep apnea, restless legs, or other sleep disorders (not including insomnia) known to affect fatigue
Use of photosensitizing medication
Plans to travel across more than 2 time zones during the study
Shift worker
Adults unable to consent, individuals who are not yet adults, pregnant women, and prisoners will be excluded from the study