1008P - Effect of protracted radiotherapy treatment on outcome of head and neck SCC patients (NEMROCK experience)

Abstract

Patients with head and neck cancer receiving radiation therapy alone or with concurrent chemotherapy often develop mucositis that may lead to unplanned treatment interruptions, these decreases in treatment intensity may reduce rates of loco-regional tumor control and survival. A total number of one hundred twenty head and neck cancer patients included in this retrospective study presented to NEMROCK between January 2005 and December 2010 after they underwent surgery and received their post operative adjuvant radiotherapy with or without concomitant chemotherapy. The impact of both overall treatment time of radiation and treatment gaps on loco regional tumor control and overall survival were studied. Radiation treatment gaps lasting 5 days or less did not influence LC (86%) at 3-years, which may suggest that the average dose intensity (>9 Gy/week), appeared high enough to compensate for few days of treatment break meanwhile patients received low DI (<9 Gy/week) had three times risk of recurrence (HR = 3.13; 95% CI, 1.47-6.64; p = 0.003). However prolongation of treatment gaps more than 10 days are related to a decrease in 3-years LCR to 40% (from 86% to 46% p = 0.001). Similar statistically significant difference in 3 years OAS was also observed among the patients with no or up to 5 days treatment gap and the patients experienced > 10 days gap (87.8% vs. 61%, p = 0.001). An increased OTT (> 60 days) and low DI (9 Gy/week) are seem to be related to a decreased OAS among our patients in multivariate analysis. In this retrospective study, patients with head-and-neck cancer, who have unplanned interruptions in radiotherapy have an increased risk of death and tumor recurrence. This analysis have several limitations. It is impossible to fully remove the effect of unmeasured factors that are associated both with presence of treatment interruptions and risk of death like mucositis, xerostomia, dysphagia, and aspiration, each of which may also be associated with decreased survival time. Thus, the observed increased risk of death associated with interruptions in radiotherapy may not be entirely attributable to the interruptions themselves.