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Erschienen in:
12.08.2019 | Original Research
Patterns of utilization and comparative efficacy of altered fractionation and concurrent chemoradiation for treatment for T2N0M0 glottic carcinoma
Erschienen in: Journal of Radiation Oncology | Ausgabe 3/2019
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Objectives
To study radiotherapeutic treatment approaches in larynx-preservation for T2N0M0 glottic carcinoma at free-standing centers in the USA.
Methods
We retrospectively audited fractionation and chemoradiation at 59 centers in 5 geographic regions from 2000 to 2015. Chi-squared test and Fisher’s exact test were used to compare frequencies, the Cox proportional hazards model and Kaplan-Meier procedure were used for survival analyses, and log-rank test to compare survival curves.
Results
Among 180 patients, chemoradiation, accelerated hypofractionation (2.25 Gy/fraction), and hyperfractionation was given to 14.4%, 13.3%, and 13.3%, respectively. Hypofractionation rates varied by geographic location: western/southern 33%, northeast 18.6%, Florida 5.6%, and Michigan 0% (p < 0.001). Conversely, hyperfractionation rates were as follows: Florida 23.6%, Michigan 14%, southern 9.5%, northeast and western 0% (p < 0.001). Hypofractionation increased from 6.3% in 2000–2004 to 25.0% in 2010–2015 (p < 0.001) and steadily declined for hyperfractionation. Chemoradiation did not vary by region but increased over time: 0% in 2000–2004, 17.6% in 2010–2015(p = 0.029).
At mean follow-up at 32.3 months, 36 months survivals were as follows: accelerated fractionation 85%, hyperfractionation 81%, and standard fractionation 66%, (p = 0.01); treatment duration < 50 days 82%, > 50 days 59% (p = 0.03). There was no difference in overall survival, progression-free survival, or locoregional-recurrence-free survival between chemoradiation and radiotherapy-only (all fractionations). Accelerated fractionation, (the fractionation with the highest survival) gave similar 36 months survivals as chemoradiation: 85% and 68%, respectively (p = 0.69). Chemoradiation worsened acute grades 2–4 toxicity rate versus radiotherapy-only: 80.8% and 54.5%, respectively (p = 0.01, univariate and multivariate).
Conclusions
Hypofractionation gave superior survival than standard fractionation for glottic T2N0M0 tumors. Its use varies among treatment centers but is increasing with time. Chemoradiation gave a lower therapeutic ratio: more than 30% greater acute toxicity without improvement of survival; yet, its use is growing over time. More explicit guidelines are needed.