Definitions and Data Collection

The care pathway interval (CPI) was defined as the number of calendar days between the first visit in the HNOC and the start of treatment (ie, the first day of radiotherapy or chemoradiation or the day of surgery). ²¹ CPI and all analysis involving CPI as a dependent or independent parameter were calculated for cases managed with curative intention. Based on internationally used cutoffs and the quality indicator norm set by the Dutch Head and Neck Society, CPI was dichotomized into patients starting treatment <30 days and ≥30 days (delayed group). ¹⁶

Patient, tumor, and treatment characteristics were collected and supplemented with CPI and follow-up data. Tumor stage was reported with the UICC TNM classification (seventh edition; Union for International Cancer Control). ²² The presence of comorbidities was graded with the ACE-27 (Adult Comorbidity Evaluation–27). ²³ Polypharmacy was defined as use of ≥5 medications.

The number of days spent in hospital (any department, excluding outpatient clinic visits) was measured in the first year after treatment initiation. For analyses, hospital admission days were dichotomized into ≤14 vs >14 days, as defined by Chesney et al. ⁹