In new research published in Cell Chemical Biology, researchers at The Scripps Research Institute (TSRI) reported that exposure to some xenoestrogens – compounds found in lentils, nuts and cereals – reversed the effects of palbociclib and letrozole on tumour growth, in ER-positive breast cancer cells in the lab.

Monday 15 January 2018      Latest research

The team found that xenoestrogens only had an effect on cells which had been administered with palbociclib and letrozole in combination, and not when the drugs were given alone.

Holly Palmer, Research Communications Officer at Breast Cancer Now, said;

“It’s intriguing that, in experiments in the lab, xenoestrogens such as those found in common foods reduced the effects of palbociclib and letrozole – a highly effective drug combination used to treat women with ER+, HER2+ breast cancer. But it’s difficult draw any conclusions about any possible effects for patients, as the interplay of metabolic processes in the body is far more complex than those seen in cells in the lab.

“Diet varies from person to person, and we don’t know what average levels are of xenoestrogens generally present in the blood, making it difficult to assess how different levels impact drug effectiveness. Further investigation is now needed to understand whether the effects of these xenoestrogens may be as strong in patients, before determining whether any guidance may be required about any foods to avoid when taking these treatments.

“Based on current evidence, patients taking palbociclib and letrozole shouldn’t be concerned about eating foods containing these compounds. We’d simply encourage them to follow a healthy and balanced diet, to keep active and to try to maintain a healthy weight.”