Oropharynx (p16-)
Notes
C019 Base of tongue, NOS
C024 Lingual tonsil
C051 Soft palate, NOS
C052 Uvula
C090 Tonsillar fossa
C091 Tonsillar pillar
C098 Overlapping lesion of tonsil
C099 Tonsil, NOS
C100 Vallecula
C102 Lateral wall of oropharynx
C103 Posterior wall of oropharynx
C104 Branchial cleft (site of neoplasm)
C108 Overlapping lesion of oropharynx
C109 Oropharynx, NOS
C111 Pharyngeal tonsil
**Note 1:** The following sources were used in the development of this schema
* SEER Extent of Disease 1988: Codes and Coding Instructions (3rd Edition, 1998) (https://seer.cancer.gov/archive/manuals/EOD10Dig.3rd.pdf)
* SEER Summary Staging Manual-2000: Codes and Coding Instructions (https://seer.cancer.gov/tools/ssm/)
* Collaborative Stage Data Collection System, version 02.05: https://cancerstaging.org/cstage/Pages/default.aspx
* Chapter 11 *Oropharynx (p16-) and Hypopharynx*, in the AJCC Cancer Staging Manual, Eighth Edition (2017) published by Springer International Publishing. Used with permission of the American College of Surgeons, Chicago, Illinois.
**Note 2:** p16 immunotesting is mandatory to use this staging system for HPV-associated cancer. HPV by in situ hybridization (ISH) may be done as an alternative. If a case of oropharyngeal cancer has p16+, then this chapter is used. If a case does not have p16 or HPV by ISH, then the case is staged by the p16- system.