I am a GP and my wife has breast cancer and is on letrozole an aromatase inhibitor.

Hi Catherine,

I am a GP and my wife has breast cancer and is on letrozole an aromatase inhibitor. I want to know if we add progesterone cream to her treatment whether it will have an adverse effect when she is already on letrozole.

Thank you,

Paul

Dear Paul,

I would first want to know whether the surgeons have also assessed her tumour for progesterone receptor status.

There are some tumours that seem to be progesterone sensitive as well as oestrogen sensitive.

Having said that and if they have not done this test I would add that in general I and other GPs using these creams and also Dr J Lee (USA) and Dr J Wright (USA) seem to aggree that we have not seen any undue tumour progression when Ca patients are on progesterone creams.

Often the patients I see feel generally better when taking the cream.

The overall impression is that progesterone is carcinoprotective and it certainly will help counteract the carcinogenic effects of oestrogen and particularly the 16-hydroxy metabolites of oestrogen metabolism.