with improved treatment response in patients with high-grade serous ovarian cancer, according to results from a two-arm pilot randomized trial that will be presented by Marchetti at the 2026 ASCO Annual Meeting (Abstract 5517). Patients assigned to short-term fasting also had longer progression-free survival than those assigned to a free diet.
“Despite advancements in surgery and chemotherapy, patients with advanced ovarian cancer still face poor outcomes,” said lead study author Claudia Marchetti, MD, of the Fondazione Policlinico Universitario Agostino Gemelli IRCCS in Rome, during a press briefing ahead of the meeting. “This highlights the urgent need for safe, low-cost, and easily implementable strategies that can enhance treatment efficacy and improve patient prognosis.”
High-grade serous ovarian cancer is often diagnosed at an advanced stage, and many patients receive neoadjuvant chemotherapy before surgery. However, most patients with advanced ovarian cancer eventually experience disease recurrence. Because insulin may support cancer growth and reduce the effectiveness of chemotherapy, the study tested whether short-term fasting could improve metabolic parameters and treatment response.
Study Methods
The prospective, two-arm trial was conducted at a single center in Rome. Eligible patients had newly diagnosed advanced high-grade serous ovarian cancer, were not suitable for primary cytoreductive surgery, and required neoadjuvant chemotherapy. Patients also had to have a body mass index of at least 19 kg/m². Major exclusions included diabetes mellitus, food allergies, eating disorders, and malnutrition.
Participants received carboplatin- and paclitaxel-based neoadjuvant chemotherapy and were randomly assigned to short-term fasting or a free diet, with evaluation for interval cytoreductive surgery after three cycles. Although a ketogenic diet arm was initially planned, it was closed early because of low compliance.
Short-term fasting was defined as fasting from 36 hours before chemotherapy until 24 hours after the end of each chemotherapy cycle, with a maximum daily intake of 350 kcal. Patients in the fasting group could consume unrestricted amounts of water and herbal tea, up to 2 liters of vegetable juice, and small amounts of light vegetable broth. Between chemotherapy sessions, they ate regularly.
The primary endpoint was reduction in mean insulin levels after three cycles of neoadjuvant chemotherapy; secondary endpoints included oncologic outcomes and toxicity, and translational analyses assessed immune system profiles.
Key Findings
Eighteen patients in each arm completed three cycles of neoadjuvant chemotherapy and were included in the analysis. Baseline characteristics and insulin levels were well balanced between the groups.
The primary endpoint was met—after three cycles of neoadjuvant chemotherapy, insulin levels increased by 9.76 µIU/mL in the free-diet group but decreased by 1.12 µIU/mL in the short-term fasting group.
Short-term fasting was also associated with improved pathologic response. At interval cytoreductive surgery, a chemotherapy response score of 3, indicating complete or near-complete response, was observed in 58.8% of patients in the short-term fasting arm compared with 17.6% of patients in the free-diet arm.
After a median follow-up of about 18 months, median progression-free survival was longer in the short-term fasting arm than in the free-diet arm, at 38 months vs 24 months, respectively.
The investigators reported no relevant differences in chemotherapy toxicity between groups, suggesting that short-term fasting during chemotherapy was safe and well tolerated. Translational analyses also showed lower levels of immunosuppressive granulocyte and monocyte subsets in the short-term fasting arm, suggesting a potentially more favorable immune environment during chemotherapy.
Commenting on the study, Eleonora Teplinsky, MD, Head of Breast and Gynecologic Medical Oncology at Valley-Mount Sinai Comprehensive Cancer Care and an ASCO Expert in gynecologic cancers, said the findings support further research into this method.
“Fasting during chemotherapy is an area of growing research interest. This pilot randomized clinical trial showed that short-term fasting before and after each chemotherapy cycle led to a reduction in insulin levels after three neoadjuvant chemotherapy cycles and improved pathologic response and progression-free survival in patients with ovarian cancer,” Dr. Teplinsky said. “While this is a small study, the findings are encouraging, support earlier data, and highlight a promising area of cancer research, with larger clinical trials now needed to build on these results.”
The authors said the findings provide a rationale for longer follow-up and larger multicenter randomized studies to validate whether short-term fasting can improve outcomes in patients with ovarian cancer.
DISCLOSURE: This was a nonprofit study conducted without commercial funding. For full disclosures of the study authors, visit coi.asco.org.
