I gave been taking letrozole pre op to shrink a 3.5cm cancer in the left breast - been on it since beginning of May, went for ultra sound on August 18th and it had reduced by 33% the breast surgeon had advised staying on this for a further 3 months to enable a lumpectomy- will it continue to work? Has said the cut off point for pre op letrozole is 9 months - if it's shrunk by 33% in the first 3 months will it continue to keep working in the next 3 months - my breast has become tender, is that a good sign of tumour shrinkage? Thank you so much...