Hi there.
Adenocarcinomas of the salivary glands are slower growing than the other head and neck cancers. However, these tumors can be invasive and spread to local and regional lymph nodes of the head and neck, including those at the side of the throat area. Some tumors would tend to metastasize to the lungs but this is seen in very late stages. Without further treatment, the 3-year survival rates for patients with this condition ranges from about 20-30%. You might want to discuss with her doctors regarding insertion of feeding tubes, or having a tracheostomy ( a tube inserted at the trachea area), so that whatever happens, no matter how large the tumor becomes, she will still be able to breath and be fed properly.
Regards and God bless.
Thank you so much. Much more Info than we had. And God's Blessings to you for, MaryS454