They found that the drug Fenretinide reduced second cancers in pre-menopausal women by 38 percent and halved the risk in those under 40. However, the cancer rate actually increased among post-menopausal women taking the drug, it said.
Fenretinide is a synthetic version of Retinol or active vitamin A, which can combat certain types of tumour.
However, Sarah Rawlings from Breakthrough Breast Cancer said: "Significantly more research is needed before any conclusions can be drawn."
"The researchers themselves say they are not yet in a position to make any clinical recommendations."
She warned that high doses of vitamin A could be harmful to unborn babies and cause other health problems.
--Edited IANS