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

INTRODUCTION: Waiting-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 METHODS: In 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. RESULTS: Median 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. INTERPRETATION: This 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.