Abstract PO4-11-03: Impact of Short Term Fasting (STF) on Fatigue developing in primary breast cancer (BC) patients receiving the Henderson or Sparano Scheme in the prospective multicentre FIT2- cohort

Abstract Background: Experimentally, it has been shown that short-term fasting (STF) induces a “protective mode” in healthy cells against chemotherapeutic toxicity while it enhances the susceptibility of tumor cells to chemotherapy. In healthy cells, fasting triggers distinct protective metabolic and gene expression changes, such as upregulation of DNA repair mechanisms, autophagy, and downshift of metabolic pathways including IGF-1-dependent signaling. This study was conducted to assess feasibility, quality of life (QoL) including chemotherapy-induced fatigue (CTF) comparing STF around each chemotherapy (4xAC or 4xEC) to a plant-based low-sugar diet (PBD). Methods: Newly diagnosed BC-patients treated by the Henderson or Sparano scheme were included in this randomised, controlled, multicenter study. CTF was assessed by the FACIT-F questionnaire before (day 0) and after chemotherapy (day 7) as well as at months 4 (V1) and 6 (V2). Results: Of the included n=106 patients, 52 were randomized to STF and 54 to PBD. n=90 (84.9%) patients obtained AC/EC+Pac and 16 (15.1%) AC/EC+Doc. FACIT-F showed no significant difference at baseline (STF 42.8; PBD 41.3; p=0.708). The differences between the corresponding FACIT-F Trial Outcome Index resp. Total FACIT-F at cycle 4 day 7 were 13.1 (SE 4.7) resp. 15.8 (SE 5.6), both in favor of STF (statistically significant (p < 0.007) and clinically relevant (minimal important difference (MID) > 5). This difference was visible for all breast cancer subtypes, i.e. luminal A & B, as well as HER2 overexpressed and triple negative tumors, with the STF group showing no clinically relevant fatigue after 4 cycles of chemotherapy (FACIT-F > 34), across all subtypes. The opposite was true for the PBD group (FACIT-F < 34) across all subtypes. FACIT-F (22.7) for PBD in HER2 overexpressed and triple negative tumors was significantly worse than those in luminal A and B patients (FACIT-F= 29.1; difference 6.4 > MID=3). STF was well tolerated and there were no serious adverse effects. Conclusion: STF during chemotherapy is well tolerated and appears to improve QoL including fatigue during chemotherapy compared to a plant-based low-sugar diet, independent of intrinsic subtypes. Citation Format: Daniela Koppold, Christian Kessler, Manfred Wischnewsky, Ixquic Alvarado, Nico Steckhan, Cornelia Kempter, Marion Paul, Barbara Brückner, Dorothea Fischer, Aysen Wunschel, Rainer Stange, Etienne Hanslian, Michael Jeitler, Andreas Michalsen. Impact of Short Term Fasting (STF) on Fatigue developing in primary breast cancer (BC) patients receiving the Henderson or Sparano Scheme in the prospective multicentre FIT2- cohort [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-11-03.