Fish oil supplements may help alleviate the painful side effects of some cancer treatments, research suggests.
Two separate studies, presented at the American Society of Clinical Oncology (ASCO) meeting in Chicago, show Omega-3 fatty acids can reduce discomfort caused by certain therapies.
The benefits were seen in some breast and bowel cancer patients, with the supplement thought to reduce inflammation.
Dr Andrew Epstein, speaking as an expert for ASCO, said: “It’s adding to the evidence base that nutritionally supplemental therapies like Omega-3 may have a place in supporting patients as they go through their cancer care.”
Around half of women taking aromatase inhibitors, a common drug for postmenopausal women with hormone receptor positive breast cancer, experience joint pain.
The hormone treatment is usually taken for between five to 10 years after surgery.
However an estimated 25% of patients stop within two years because they cannot endure the side effects, lead author Dr Sherry Shen, of the New York Presbyterian Hospital, said.
“This is a real problem, the joint pain,” she told the Press Association.
“And it’s really preventing women from taking these medications that are designed to prevent them getting a recurrence of their breast cancer.”
An analysis of a 2015 study of 249 patients found Omega-3 helped relieve symptoms among obese women taking the drug, who are more likely to experience joint pain.
Those with a BMI above 30 – around 140 patients – recorded an average “worst pain” score of seven out of 10 before taking the supplement or a placebo.
This figure had dropped to 4.36 among the Omega-3 group and 5.7 in the placebo group after six months, the research found.
There was no significant change among non-obese patients.
Omega-3 fatty acids also appear to help some bowel cancer patients experiencing inflammation, a separate study by researchers at the Camargo Cancer Centre in Brazil suggests.
The side effect is extremely common among those receiving chemoradiotherapy.
A study of 114 patients with locally advanced rectal cancer found those given fish oil capsules during the preoperative treatment went on to have fewer of these symptoms.
At the end of treatment they had less difficulty urinating, while in the next month they experienced less general pain and less discomfort while having sex than those who had not taken the supplement.
In the immediate run-up to surgery, around eight weeks after chemoradiation, these patients had less appetite loss, buttock pain and bloating.
Dr Epstein, a clinical oncologist at Memorial Sloan Kettering Cancer Centre in New York, said the two studies show “the anti-inflammatory benefits of a relatively cheap, well-tolerated supplement”.
Dr Lisa Wilde, director of research at Bowel Cancer UK and Beating Bowel Cancer, said: “This small study explores how fish oil could help improve treatment success and quality of life for some patients with late stage rectal cancer.
“Over half of all bowel cancer patients in the UK are diagnosed at a late stage.
“Furthering our understanding of who might benefit from dietary supplements and at what stage in their treatment could ultimately help improve the lives of those living with and beyond the disease.”
Jane Murphy, clinical nurse specialist at Breast Cancer Care, said: “It’s really interesting to see different avenues are being explored to help women adapt to life after breast cancer, which can be incredibly daunting and difficult.
“Women regularly call our helpline struggling with debilitating side effects from long-term breast cancer treatments, like aromatase inhibitors, and joint pain is a particularly common problem.
“While these drugs are invaluable in helping to stop the cancer returning, they can make moving forward feel like an uphill struggle.
“However, this is a small study so more research is needed before we have clear-cut answers on the benefits of fish oil for easing pain from breast cancer treatment.”