This multicenter randomized (1:1) phase 2 study is designed to assess the efficacy of the Walk with Ease exercise program on improving fatigue after adjuvant radiotherapy compared to usual care in 50 women with stage 0-3 breast cancer who have undergone breast surgery.

Prior to initiation of radiation, during the last week, and 4-6 weeks post radiation, women in both arms will complete a number of surveys including questionnaires on fatigue, pain, depression, sleep, and social support. In addition, a blood sample will be collected prior to, during the last week of radiation, and 4-6 weeks post radiation to explore measures of inflammatory biomarkers, and their potential association with exercise and fatigue.

Recruitment, consent, and randomization will occur at first postoperative visit with a radiation oncologist. A 1:1 randomization will occur between WWE program and usual care (scripted discussion on benefit of exercise during radiotherapy). Prior to initiation of radiation, women in both arms will complete 68 questions from questionnaires on pain, depression, sleep, and social support. In addition, peripheral blood will be drawn for analysis of pre-radiation measures of inflammatory biomarkers. Women randomized to the WWE program will also receive a daily walking log that they will be asked to fill out and return on the last week of radiation (6 weeks for standard fractionation and 4.5 weeks for hypofractionation), and at 4-6 weeks post radiotherapy. Also, on their last week of radiotherapy and 4-6 weeks after radiotherapy all patients will repeat the questionnaires and a blood draw for measures of inflammatory biomarkers.

Contact with study participants will be at 3 points in time after enrollment and randomization:

Baseline: At this meeting, requirements of the study will be reviewed, and study materials provided (for control arm: a one page explanation discussing the potential benefits of exercise on fatigue, for experimental arm: WWE workbook, and printed walking log). Participants will complete questionnaires and undergo other assessments including a blood draw. For those on the experimental arm, they will be asked to begin the walking program within a week, noting their walking experience in their daily log.

Last week of radiation: All participants will repeat questionnaires and other assessments during any day of their last week of radiation. A repeat blood draw will be taken. In addition those on the WWE arm will have their walking log reviewed. For those receiving hypofractionated radiotherapy, this will occur at week 4. For those receiving standard fractionation this will occur at week 6.

4-6 weeks following end of radiation: All participants will repeat questionnaires and other assessments. A repeat blood draw will be taken. In addition those on the WWE arm will have their walking log reviewed.

Patients randomized to the usual care arm will receive a document with information on exercise to improve fatigue during radiotherapy. The sheet will summarize the findings of the 3 randomized studies on exercise intervention during radiotherapy.

The primary activity required of study subjects is a 4-6-week self-directed (non-group) WWE walking program that participants do at a place and time that is convenient for them. Participants are asked to walk at a safe and comfortable pace, increasing their minutes per day at a rate they can sustain, with the ultimate goal of 30 minutes/day for at least 5 days/week. They are asked to maintain a daily walking log that is provided to them, entering total minutes per day.

Inclusion Criteria:

• ≥65 years of age
• Histologically confirmed Stage I, II or III breast cancer status post breast surgery with or without adjuvant chemotherapy.
• Scheduled to undergo hypofractionated or standard fractionated radiation therapy to the breast or chest wall.
• English speaking.
• IRB approved, signed written informed consent.
• Approval from their treating radiation oncologist to engage in moderate-intensity physical activity. This will be obtained by the study research coordinator and documented on the study screening form (attached).
• Patient-assessed ability to walk and engage in moderate physical activity Willing and able to meet all study requirements.

Exclusion Criteria:

• One or more significant medical conditions that in the physician's judgment preclude participation in the walking intervention.
• Receiving accelerated partial breast irradiation.
• Unable to walk or engage in moderate-intensity physical activity.
• Already participated in Walk with Ease Program.
• Already actively walking (≥120 minutes per week).