Researchers presented intriguing findings at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, suggesting that a short period of fasting around chemotherapy treatments may help some patients with advanced ovarian cancer respond better to treatment.
While the study was small and more research is needed, the results have generated excitement because fasting is a relatively simple, low-cost intervention that could potentially improve outcomes alongside standard cancer care.
What did the study find?
The phase II study included 36 women with newly diagnosed stage III or IV high-grade serous ovarian cancer who were receiving chemotherapy before surgery.
Half of the participants followed a fasting protocol, consuming very limited calories for 36 hours before chemotherapy and 24 hours afterward. The other half continued eating normally during treatment.
The results were encouraging:
- Nearly 60% of patients in the fasting group achieved a near-complete or complete tumor response before surgery, compared with 17% of patients who ate normally.
- Patients who fasted experienced a median progression-free survival of 38 months, compared with 24 months in the control group.
- Insulin levels decreased in the fasting group but increased in the control group, supporting the researchers’ theory that fasting may help create a less favorable environment for cancer growth.
- The fasting approach appeared safe and feasible, with all patients in the fasting group completing treatment and experiencing similar rates of chemotherapy-related side effects as those who did not fast.
Researchers think fasting may improve chemotherapy response by lowering insulin and IGF-1 levels, which have been linked to tumor growth and resistance to cancer treatment.
Why is this important?
Advanced ovarian cancer remains challenging to treat. Although chemotherapy and surgery have improved outcomes, many patients eventually experience disease recurrence.
These findings suggest that something as simple as carefully timed fasting could potentially make chemotherapy more effective. If larger studies confirm these results, fasting could become an accessible strategy that patients may be able to use alongside standard treatment.
Another reason these findings are attracting attention is that fasting doesn’t involve a new drug, specialized equipment, or expensive technology. Instead, researchers are exploring whether changing the body’s metabolism for a short period can help cancer treatments work better.
What could this mean for patients?
For patients currently undergoing treatment for ovarian cancer, this study offers hope that researchers are continuing to explore new ways to improve outcomes beyond traditional therapies.
However, it’s important to remember that fasting isn’t considered a standard part of ovarian cancer treatment. The results come from a small, early-stage study, and larger clinical trials are needed before doctors can confidently recommend this approach for everyone.
Still, the findings may encourage conversations between patients and their healthcare teams about nutrition, metabolism, and supportive strategies that could complement treatment.
Should you try fasting with ovarian cancer?
Although fasting appeared safe in this study, it may not be appropriate for every patient. Cancer treatment can already place significant stress on the body. Some patients may be at risk for:
- Weight loss
- Malnutrition
- Dehydration
- Low energy levels
- Other medical complications that could make fasting unsafe
Factors such as age, overall health, body weight, treatment type, and existing medical conditions can all affect whether fasting is appropriate.
Importantly, the patients enrolled in this study were carefully selected, monitored by medical professionals, and followed a structured fasting plan. Attempting to fast on your own during chemotherapy without medical guidance could potentially do more harm than good.
If you’re interested in fasting or other dietary approaches during treatment, speak with your oncologist and oncology dietitian first. They can help determine what is safe and appropriate for your individual situation.
Understanding the study’s limitations
While the results are promising, several limitations should be considered:
- The study was small. Only 36 patients participated, making it difficult to know whether the results would be the same in a larger population.
- The findings need confirmation. Larger, multicenter clinical trials are necessary to verify that fasting truly improves treatment outcomes.
- Overall survival has not been determined. While patients who fasted went longer before their cancer progressed, researchers don’t yet know whether fasting ultimately helps patients live longer.
- The study focused on a specific group of patients. Participants had advanced high-grade serous ovarian cancer and were healthy enough to tolerate the fasting protocol. The results may not apply to all ovarian cancer patients.
Looking ahead
Researchers are already planning larger studies to better understand whether fasting can consistently improve outcomes and which patients might benefit most.
As scientists continue to explore the connection between metabolism, nutrition, and cancer treatment, studies like this may help uncover additional ways to support patients and improve outcomes in ovarian cancer.
Looking for more information? Access trusted educational resources designed to help you navigate ovarian cancer treatment.
