Materials and Methods
After obtaining approval from the Institutional Review Board, a
case-series reviewing patients treated surgically for squamous cell
carcinoma of the upper aerodigestive tract at our academic institution
who then underwent post-operative radiation therapy between 2012 and
2016 was conducted. Due to the retrospective nature of this study,
consent was waived. A database of head and neck cancer patients treated
at INSTITUTION BLINDED FOR REVIEW during these years was used to
identify individuals who met the criteria for the study.
Patients were included if over eighteen years of age at the time of
surgery, a pathology-confirmed diagnosis of squamous cell carcinoma,
primary surgical resection at INSTITUTION BLINDED FOR REVIEW, and the
need for PORT following primary resection. Patients who underwent
induction chemotherapy prior to surgery, those who received salvage
surgery following prior treatment with radiation therapy, and patients
who declined recommended PORT were excluded from the study.
After identifying subjects through the database, data points on patient
demographics, pathology reports, surgery, and treatment characteristics
were collected. Patient demographic characteristics included: age,
gender, race, insurance status, alcohol use, and tobacco use. Pathology
characteristics included: primary tumor site, TNM staging,
human-papillomavirus (HPV) status, and any recurrence as diagnosed by
biopsy, imaging, or clinical diagnosis. Surgery characteristics
included: surgery date, discharge date, post-operative length of stay
greater than or equal to eight days, post-operative complications
(including wound complications, wound infections, pneumonia, or need for
repeat operation), readmissions within thirty days of surgery,
post-operative rehabilitation center admission, post-operative dental
extractions, and post-operative feeding tube placement. Finally,
adjuvant therapy characteristics included: history of prior head and
neck cancer treatment, facility location of adjuvant therapy, need for
concurrent chemotherapy, date of first and last radiation session, days
to initiation of radiation from surgery, prescribed number of radiation
fractions, completed number of radiation fractions, prescribed number of
chemotherapy treatments, and completed number of chemotherapy
treatments.
We utilized available scanned treatment reports in our electronic
medical record for patients who received adjuvant therapy at outside
institutions. Facilities were contacted if this information was
incomplete or missing from the record and updated accordingly.
Descriptive statistics, including frequencies and proportions for
categorical variables and means, standard deviations, medians,
25th and 75th percentiles for
continuous measures, were calculated for all measures of interest.
Non-parametric tests (Wilcoxon Two-Sample Test and Kruskal-Wallis Test)
were used to test for differences in continuous measures among study
groups, while Fisher’s Exact Test was used to test if the measure was
categorical. The Kaplan-Meier method was used to estimate delays in
treatment; Cox Proportional Hazards models were used to assess the
association between delays and study measures in both univariate and
multivariate models. P-values < 0.05 were considered to be
statistically significant; SAS (version 9.4, Cary, NC, USA) was used for
all analyses.