Tumor progression in waiting time for radiotherapy in head and neck cancer

IntroductionWaiting-time prior to radiotherapy is a well-known problem. This study aims to determine the impact of time on tumor growth in a patient population with squamous-cell carcinoma of the head and neck (SCCHN).Material and methodsIn a consecutive cohort, all patients with both a diagnostic scan and a treatment-planning scan were identified. In total 648 patients were seen, and 414 treated with primary radiotherapy. Ninety-five had two scans and 61 sets were eligible for comparison. Endpoints were change in tumor volume, tumor volume doubling time (TVD) and disease progression measured by TNM-classification and RECIST criteria.ResultsMedian interval between eligible scans was 28 (5–95) days. Thirty-eight (62%) had measurable increase in tumor volume, median 46% (6–495%). For all patients TVD was median 99 days, but for the half of patients with fastest growing tumors TVD was 30 days (15–41). Tumor volume increase was significantly correlated to time and histological differentiation. Twelve (20%) developed new lymph-node metastasis and 10 (16%) progressed in TNM-classification. Evaluated by RECIST criteria 18 (30%) patients had progressive disease.InterpretationThis study shows a negative impact of waiting time in patients with SCCHN. Within an average time of 4 weeks the majority of the patients developed significant signs of tumor progression. It was not possible to define a threshold for acceptable time intervals in order to avoid volume changes, or to define a subgroup that has no negative impact of delay.