Abstract PD5-11: Pilot study to assess prolonged nightly fasting in breast cancer survivors (LONGFAST)
Authors: O'Donnell Elizabeth K. , Shapiro Yael N. , Comander Amy , Isakoff Steven J. , Moy Beverly , Spring Laura , Wander Seth , Kuter Irene , Shin Jennifer , Younger Jerry , Specht Michelle , Kourniotis Chryssanthi , Sullivan Carol , Winters Loren , Horick Nora , Peppercorn Jeffrey 
Published: March 2022

Background: Prior, retrospective analysis of nightly fasting among women with breast cancer suggests that fasting less than 13 hours per night may be associated with higher risk of breast cancer recurrence. Small studies suggest that fasting duration can influence inflammation, obesity, sleep, and other potential mediators of breast cancer recurrence risk. Prolonged overnight fasting is a simple, nonpharmacological behavioral intervention strategy that may be doable for most patients. We designed this pilot study to prospectively evaluate the feasibility of prolonged overnight fasting among breast cancer survivors. Methods: We designed a single-arm, pilot study to evaluate the feasibility of fasting for 13 hours overnight for a 12-week period among women with a history of early stage breast cancer (I to III) who had completed initial cancer therapy at least 6 months prior. Baseline and end of study assessments included measurements of body mass index (BMI), quality of life (QOL) (Functional Assessment of Cancer Therapy - General (FACT-G)), mood (Hospital Anxiety and Depression Scale (HADS)), fatigue (Functional Assessment of Chronic Illness Therapy (FACIT) - Fatigue), levels of physical activity (Godin Leisure-Time Exercise Questionnaire), and blood biomarkers (expanded lipid profile, hemoglobin A1c, C-reactive protein, interleukin-6, tumor necrosis factor alpha, leptin, adiponectin). Patient-reported outcome (PRO) surveys were also administered at 6 weeks. Feasibility was defined as ≥ 60% of participants documenting fasting in the food diary for 13 hours on at least 70% of nights during the study period. Changes in study measures from baseline were evaluated using Wilcoxon signed-rank tests. Results: Between July 2020 and January 2021, we enrolled 40 women with a history of breast cancer. Participants had a median age of 59.9 (range 34.9-76.3) and median time since diagnosis was 4.5 years (range 0.8-20.7). At baseline, BMI was normal (18.5-24.9) in 40.0%, overweight (25-29.9) in 37.5%, and obese (≥30) in 22.5%. Forty-two and a half percent had Stage I cancer, 42.5% stage II, and 15.0% stage III. Sixty-five percent were on hormonal therapy. Ninety-five percent of participants fasted ≥ 13 hours for at least 70% of study days (95% CI 83%-99%). At 6 weeks, there was a statistically significant improvement in anxiety (p=.0007). No other significant changes were seen in PROs. At 12 weeks, there were statistically significant improvements in BMI (p=.0072), anxiety (p=.0141), depression (p=.0048), and fatigue (p=.0105). There was no association between change in BMI during the study and baseline BMI category, age, or endocrine therapy. There was no significant change in overall QOL, physical activity levels, or blood biomarkers at 12 weeks. Conclusions: Prolonged overnight fasting is feasible in the breast cancer population and may improve BMI, mood, and fatigue without a detrimental effect on overall QOL. The data from this study support the need for a larger, longer randomized study of prolonged overnight fasting in the breast cancer population to further evaluate the effects on body composition, mood, QOL, metabolic markers, and risk of recurrence.

Table 1.Impact of Prolonged Overnight Fasting among Breast Cancer SurvivorsStudy AssessmentMedian at baselineMedian at 12 weeksMedian within-participant changep-valueBody Mass Index (kg/m2)26.4225.80-0.380.0072HADS - Depression1.001.00-1.000.0048HADS - Anxiety4.504.00-0.500.0141FACIT - Fatigue47.5049.821.000.0105FACT-G - Quality of Life95.2096.840.910.4933Physical Activity Level40.5039.000.000.3340Hemoglobin A1c (mg/dL)5.455.400.000.2758High-density lipoprotein (mg/dL)72.0073.00-2.000.4688Low-density lipoprotein (mg/dL)92.0099.001.000.5626Total Cholesterol (mg/dL)193.00192.003.000.6569C-reactive protein (mg/L)1.500.90-0.100.1043Interleukin-6 (pg/mL)2.001.90-0.300.1213Tumor Necrosis Factor α (pg/mL)0.740.74-0.050.2898Adiponectin (ug/mL)12.0012.000.000.0682Leptin (ng/mL)7.158.30-0.100.8418

Citation Format: Elizabeth K. O'Donnell, Yael N. Shapiro, Amy Comander, Steven J. Isakoff, Beverly Moy, Laura Spring, Seth Wander, Irene Kuter, Jennifer Shin, Jerry Younger, Michelle Specht, Chryssanthi Kourniotis, Carol Sullivan, Loren Winters, Nora Horick, Jeffrey Peppercorn. Pilot study to assess prolonged nightly fasting in breast cancer survivors (LONGFAST) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD5-11.