Obesity might block breast cancer treatment: NZ study

Obesity could hinder the effects of a common drug that is used as part of a treatment to fight breast cancer in post-menopausal women, New Zealand scientists said Wednesday.

Aromatase inhibitor (AI) drugs stopped the production of estrogen which stimulated the growth of hormone-receptor-positive breast cancer cells, but they could be less effective in obese women because of the greater quantity of aromatase in peripheral fatty tissue, said Auckland University cancer epidemiologist Professor Mark Elwood.

A review of eight earlier studies to assess the effect of obesity on AI efficacy in breast cancer treatment showed a trend towards a negative effect, Elwood said in a statement.

"Many questions remain unanswered in this complex scenario and information is needed before recommendations for the improved use of AIs for obese patients could or should be made," said Elwood.

Obesity was defined as a global pandemic and more than half of the world's population was expected to be obese by 2030.

Obesity was associated with an increased risk of several cancers and poorer outcomes for cancers such as colon, endometrial and post-menopausal breast cancer.

AIs were considered the best hormonal therapy to start with when treating early-stage, hormone-receptor-positive breast cancer.