Variables of Interest
Variables studied were divided into four separate categories: Patient,
tumor, facility, and treatment characteristics. Patient characteristics
include age, gender, race, and comorbid disease as calculated by the
Charlson-Deyo Score10. Insurance status was collected
and divided based on uninsured, private, or government insurance status.
Tumor characteristics collected include the clinical T and N
classification. The TNM editions captured in this data set include the
6th and 7th edition for which the
staging of OPSCC remained the same.11 Because the
objective of the study was to predict primary treatment modality, any
information derived from the time of treatment was excluded. This
includes pathological TNM staging, grade, extracapsular spread,
perineural invasion and other variables unless the information could
clearly be identified as obtained through pre-treatment biopsy. Facility
characteristics explored include whether the treating hospital is a
community program, academic program, integrated network cancer program,
or other. Facility location was also included to determine if
geographical location affects treatment type. The NCDB divides the
locations into New England, Middle Atlantic, South Atlantic, East North
Central, East South Central, West North Central, West South Central,
Mountain and Pacific. Primary treatment modality was divided into two
categories; surgical and non-surgical treatments. Non-surgical
treatments include primary radiation alone or with chemotherapy. The
reason for lack of surgery, radiation, or other treatment was also
collected and explored.