Abstract 4369342: A single-center experience of oncology rehabilitation to facilitate cardiopulmonary fitness recovery among breast cancer patients receiving chemotherapy.

Background: Oncology rehabilitation (OR) may facilitate recovery of cardiopulmonary fitness (CRF) following cytotoxic chemotherapy in breast cancer (BC), however there is no consensus on who should be referred, or the optimal timing in relation to chemotherapy. We aimed to characterize OR utilization, timing, and efficacy among patients referred for OR within our institution. Methods: BC patients were eligible for this retrospective cohort study if they received chemotherapy, participated in OR, and underwent at least one CRF assessment. The OR program (Providence Cancer Institute (Anchorage, Alaska)) was modeled after cardiac rehabilitation, consisting of individualized exercise programs prescribed by a licensed cancer physical therapist. Metrics of OR utilization included timing of initiation (before during, or after chemotherapy) and number of therapeutic sessions. Metrics of OR efficacy included maximal oxygen consumption (VO 2 max) estimated from a sit-to-stand and/or six-minute walk test and left ventricular ejection fraction (LVEF) measured by transthoracic echocardiogram. Results: Between 2015-2024, 162 early stage BC patients participated in OR. Timing of OR initiation varied, with 31% (n=49) enrolling before chemotherapy, 26% (n=43) during chemotherapy, and 43% (n=70) after. Participants received a mean of 17 OR sessions, with patients enrolling after chemotherapy attending less sessions than those that attended before or during chemotherapy. Baseline VO 2 max was higher in patients commencing OR before chemotherapy (p<0.05). However, the change in VO 2 max was greater in patients commencing OR after chemotherapy (before: 0.47; during: 0.51; after: 0.70) although not significant. and in patients that attended ≥ 10 compared to <10 OR sessions (p<0.01; before: 0.90 vs. -0.97, during: 1.20 vs. -0.97, after: 0.75 vs. 0.47ml/kg/min). LVEF did not differ appreciably across subgroups or following OR. Results shown in the Table. Conclusion: BC chemotherapy patients receiving OR in our institution experienced modest improvements in VO2max, with greater improvement among patients that attended ≥ 10 sessions. Timing of initiation did not influence outcomes significantly, therefore it would be reasonable to encourage OR referral either before, during, or after receipt of chemotherapy. Additional patient advocacy and research is required to increase OR utilization, determine best practices, and elucidate the benefits of OR.