A feasibility randomised controlled trial of short-term fasting prior to CAPOX chemotherapy for stage 2/3 colorectal cancer: SWiFT protocol

BACKGROUND: Capecitabine and oxaliplatin (CAPOX) chemotherapy is a standard treatment for stage 2/3 colorectal cancer. Treatment is associated with dose-limiting toxicities such as neutropenia, vomiting, diarrhoea, and stomatitis. Short-term fasting prior to chemotherapy may help protect normal cells from the toxic effects of chemotherapy by allowing them to conserve energy for maintenance and repair. However, there is a lack of evidence to support the efficacy of short-term fasting in protecting against chemotherapy-related toxicities in humans, and it is not known whether people due to undergo chemotherapy will be willing and able to follow a short-term fast. Preliminary data confirming this is feasible are required before adequately powered trials can be designed and conducted. METHODS: The short-term, water only, fasting trial (SWiFT) is a two-armed feasibility randomised controlled trial, aiming to recruit 30 people scheduled to begin routine treatment with CAPOX chemotherapy for stage 2/3 colorectal cancer. Participants will be randomly allocated, in a 1:1 ratio, to either a 36-h fast or standard dietary advice prior to chemotherapy administration for the first 3 cycles of chemotherapy. The primary outcome measures will assess the feasibility of the trial and include: adherence to intervention, recruitment, retention, and data completion rates as well as the acceptability of the intervention which will be qualitatively assessed. The secondary outcome measures aim to provide further information on possible outcomes of interest for a definitive trial and include side effects of chemotherapy, quality of life, markers of cellular metabolism and inflammation, appetite, and sarcopenia. DISCUSSION: It is not known whether it is possible to recruit to a trial of short-term fasting in this population, or whether participants would be able to adhere to the intervention. Therefore, we aim to test the feasibility of a pre-chemotherapy, 36-h, water-only fast in people receiving CAPOX chemotherapy for stage 2/3 colorectal cancer. TRIAL REGISTRATION: This trial has been registered with the ISRCTN Registry. Trial registration no: ISRCTN17994717. Date of registration: 23 October 2018. URL: http://www.isrctn.com/ISRCTN17994717