Do you attempt to spare the submandibular glands in head and neck IMRT?

I do too. The primaries I consider electively treating 1B nodal station are: oral cavity, nose and anterior nasal cavity, lip, medial cheek/mid face, and node positive parotid. The submandibular gland itself is devoid of lymph nodes and is rarely ever involved by Sq cell Ca (versus the parotid gland). With unilateral techniques using proton therapy, I am finding that it is also possible to spare the SMG while treating level 1B. Dr. Eisbruch's group established a guideline for a mean dose of 39 Gy. We do try to push as low as possible. One of the main take home messages is that 1B is at very low risk of involvement in oropharynx ca that have not crept into the oral cavity.

There are no lymph nodes in the submandibular gland! Avoiding the gland in the CTV minimizes dose to the oral cavity, which is critical.

I do and I spare as low as possible.