Author/Editor		Žumer, Barbara; Pohar Perme, Maja; Jereb, Simona; Strojan, Primož
Title		Impact of delays in radiotherapy of head and neck cancer on outcome
Type		članek
Vol. and No.		Letnik 15, št. 1
Publication year		2020
Volume		str. 1-10
ISSN		1748-717X - Radiation oncology (London, England)
Language		eng
Abstract		Background: In head and neck cancer (HNC), the relationship between a delay in starting radiotherapy (RT) and the outcome is unclear. The aim of the present study was to determine the impact of the amount of time before treatment intervention (TTI) and the growth kinetics of individual tumors on treatment outcomes and survival. Methods: Two hundred sixty-two HNC patients with 273 primary tumors, treated with definitive (chemo) RT, were retrospectively analyzed. The TTI was defined as the time interval between the date of histopathologic diagnosis and the first day of the RT course. Volumetric data on 57 tumors were obtained from diagnostic and RT planning computer tomography (CT) scans in order to calculate the tumor growth kinetic parameters. Results: No significant association between locoregional control or cause-specific hazards and TTI was found. The log hazard for locoregional recurrence linearly increased during the first 40 days of waiting for RT, although this was not significant. The median tumor volume relative increase rate and tumor volume doubling time was 3.2%/day and 19 days, respectively, and neither had any impact on locoregional control or cause-specific hazards. Conclusion: The association between a delay in starting RT and the outcome is complex and does not harm all patients waiting for RT. Further research into imaging-derived kinetic data on individual tumors is warranted in order to identify patients at an increased risk of adverse outcomes due to a delay in starting RT.
Keywords		rak glave in vratu radioterapija zamuda pri zdravljenju head and neck cancer radiotherapy treatment delay