<prompt> Aromatase inhibitors in Ca breastLetrozoleAnastrozoleExemestaneTamoxifen  <response>: letrozole is nonsteroidal competitive inhibitor of enzyme aromatase this enzyme conves adrenal androgen to oestrogens it is used an adjuvant endocrine therapy in post menopausal women with hormone sensitive breast carcinoma ref ;page no;551 5th edition of SRB;S Manual of SURGERY 