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.