Can Lezra Be Taken For Infertility?

Hi! I have been married for 5 and a half years, but still not able to concieve. 2 years back I had a D & C to remove a polyp due to which I had irregular menstural bleeding. After D & C, my periods have been regulated to some extent. Then about 6 month ago, I had my periods disappeared for 2 months, which on diagnosis doctor determined a cyst in my ovary. she gave me injection of IVF-C 1/m stat and tablet primolute-N for 3days, after which i get my periods back to normal. Now, in order to concieve, my gynaecologist Dr. Shaheen Zaffar gave me Ovi-f for 3 cycles, but still i didnt concieve. Now , after one month gap, she recommended me Lezra (letrozole 2.5 mg) for 3 cycles. to be taken from 1st to 5th day of mensus. I come to know from few sources, tht lezra is given for the cure of breast cancer. I want to ask can I take this drug for my case (infertility), as suggested by my doctor?