Short-Term Fasting During Ovarian Cancer Chemotherapy May Improve Response
A small randomized ASCO 2026 study suggests carefully supervised short-term fasting around chemotherapy may lower insulin levels and improve treatment response in advanced ovarian cancer.
A small Italian randomized trial found that patients with advanced high-grade serous ovarian cancer who followed a short-term fasting protocol during neoadjuvant chemotherapy had lower insulin levels, higher pathologic complete response rates, and longer median progression-free survival compared with patients who continued a regular diet. The results are promising but early, and fasting during cancer treatment should only be considered under medical supervision.
Study Details
Advanced ovarian cancer remains difficult to treat, especially for patients who are not candidates for immediate surgery. Many patients first receive neoadjuvant chemotherapy, usually before interval debulking surgery. The goal is to shrink the cancer, improve the chance of complete surgery, and delay progression.
This study focused on a simple but biologically interesting idea: could reducing insulin and related growth signals make chemotherapy work better? Investigators hypothesized that short-term fasting may create a metabolic environment that is less supportive of tumor growth and more favorable for chemotherapy response.
Methodology
Researchers conducted a prospective, open-label, exploratory randomized trial in patients with newly diagnosed advanced high-grade serous ovarian cancer who were not suitable for primary cytoreductive surgery.
Patients in the fasting group began fasting 36 hours before each chemotherapy cycle and continued until 24 hours after chemotherapy. During that fasting window, they consumed about 350 calories per day, with water, herbal tea, vegetable juice, and small amounts of light vegetable broth. Between chemotherapy cycles, they returned to their regular diet. Patients in the control group continued their regular diet throughout treatment.
The primary endpoint was the change in mean insulin levels, measured during the neoadjuvant chemotherapy period. Patients received three chemotherapy cycles at 21-day intervals.
Key Findings
Lower insulin levels: At the end of neoadjuvant chemotherapy, insulin levels were significantly lower in the fasting group than in the regular-diet group.
Higher pathologic complete response: The fasting group had a pathologic complete response rate of 58.8%, compared with 17.6% in the control group.
Longer progression-free survival: Median progression-free survival was 38 months in the fasting group versus 24 months in the control group.
Tolerability looked reasonable but needs caution: Overall chemotherapy toxicity did not differ significantly between groups, although grade 3/4 hematologic toxicity was numerically higher in the fasting group.
Possible immune effect: Translational analyses suggested better anticancer immune activity in the fasting group, including lower levels of suppressor granulocytes and monocytes.
Implications for Practice
For patients, this study is important because it points to a low-cost supportive strategy that may improve chemotherapy response. But the most important practical message is caution. Cancer treatment is already physically demanding, and fasting can be risky for some patients, especially those with frailty, diabetes, poor nutrition, low body weight, kidney disease, or treatment-related nausea. This should not be attempted without an oncology team and nutrition support.
For healthcare providers, the study adds to a growing interest in metabolic modulation during cancer therapy. The signal is clinically meaningful, but the evidence remains early because this was a small pilot trial with 36 adherent patients in the final analysis. The findings should be viewed as hypothesis-generating until larger randomized multicenter trials confirm whether the benefit is real, reproducible, and safe across broader ovarian cancer populations.
The larger idea is not that fasting is a replacement for chemotherapy. It is that metabolic timing around chemotherapy may eventually become part of a more personalized supportive-care strategy. If confirmed, this could be especially relevant because it does not depend on a new expensive drug and may be feasible across many treatment settings.