More treatment

I have not been on the site for ages but have a query I think someone may be able to help with. I am 4 years past op etc and 2 1/2 years post Herceptin. I have now been diagnosed with a lesion on my lung. It is not known what it is and a biopsy is said to be almost impossible to get. Lots of discussions going on between the medics. CT scans show that the lesion has grown very slightly since I stopped the Herceptin. I suspect that the Herceptin may have held it in abeyance. Can anyone with knowledge of this help please?