What mucosal surfaces do you commonly cover with HPV-positive squamous cell carcinoma of the head and neck of unknown primary?

This is an interesting question. Many radiation oncologists are eliminating the nasopharyngeal mucosa from the field when designing plans for “comprehensive mucosal irradiation” in cases of unknown primary head and neck cancers with HPV or p16 positive squamous histology. I am currently not comforta...

Oropharynx bilaterally in the US and Europe. You have to treat the RP nodes so include the nasopharynx with tight margins plus bilateral necks.

In the words of @Dr. First Last, "the cervical lymph node area most often involved with cancer from an unknown H&N primary site is level II. The most likely primary tumor sites are the base of tongue and the tonsillar fossa. Accordingly, our philosophy has been to treat the unknown primary of the H&...

Worked with ASCO on a guideline paper for unknown primary where we address this: Maghami et al., PMID 32324430.

Ultimately, I think the highest risk areas will be ipsilateral oropharynx (tonsil & BoT). These odds probably don't change much between HPV+ and HPV-.

For an HPV-associated CUP, if we are covering mucosal sites, we treat the entire oropharynx and nasopharynx. The latter is biased by our a) treating RP nodes, and b) ~ 1/3 of our NPC population is HPV-associated. Granted it is hard to make a strong argument that even more tailored approaches such as...

Ofo et al., PMID 30419564.

None for well selected patients if you believe in TORS/TOLM/SOHND —> observation. Should include in the informed consent discussion.

The UKP issue is somewhat complex and there are 2 main schools of thought. Treat comprehensively the involved neck + electively the mucosal sites + CL neck vs. only the involved neck. When a surgeon manages an N1 neck w/o RT, he/she is not concerned about CL neck or mucosal sites. To me, the first s...

2 interesting articles on the subject:

Perkins et al., PMID 22801890.

Distribution of primaries found by random biopsy/tonsillectomy at UF

There have been several more series, omitting contralateral neck and elective mucosa depending on the scenario. Guidelines from Spain.

Rodríguez et al., PMID 30196912