Failure patterns of head and neck squamous cell carcinoma treated with radical radiotherapy by intensity modulated radiotherapy technique using focal volume and dosimetric method.

BACKGROUND: Labeling locoregional failures in head and neck cancer (HNC) as "local" and "regional" becomes incomplete when treating with intensity modulated radiotherapy (IMRT). Target delineation and delivery errors, dose in-homogeneity complicate the assessment of failures. A combination of focal point and dosimetric method might attempt at simplifying failure analysis. METHODS: One hundred eleven patients with locally advanced HNC treated with chemoradiation using IMRT were enrolled. Patients with documented failure had their recurrence volume assessed using focal point and dosimetric method. RESULTS: With a median follow-up of 20 (range 0-39) months and median locoregional control (LRC) of 30 (range 24.8-34.5) months, the patients had a 3-year overall survival and LRC of 70.6% and 48.9%, respectively. Of 39 failures, there were 69.2%, 7.6%, 5.1%, 12.8%, and 5.1% type A, B, C, D, and E, respectively using the focal point and dosimetric method. CONCLUSION: With the current classification, majority of the recurrences were high dose failures suggesting inherent radioresistance. While minority of failures were potentially preventable and needed modifying existing IMRT workflow.

Randomized controlled study comparing simultaneous modulated accelerated radiotherapy versus simultaneous integrated boost intensity modulated radiotherapy in the treatment of locally advanced head and neck cancer.

OBJECTIVES: Comparison of two fractionation schedules of intensity modulated radiotherapy (IMRT) for locally advanced head and neck cancer - simultaneous integrated boost (SIB-IMRT) and simultaneous modulated accelerated radiotherapy (SMART) boost in terms of toxicity and survival end-point measures. PATIENTS AND METHODS: Sixty patients with locally advanced head and neck cancer were randomized in two treatment arms (SIB-IMRT [control arm] and SMART boost arm [study arm]). In the control arm, patients received 70, 63 and 56 Gy in 35 fractions to clinical target volumes (CTV) 1, 2 and 3, respectively. In the study arm, patients received 60 and 50 Gy to CTV 1 and CTV 3, respectively. Toxicities, progression free survival (PFS) and overall survival (OS) were compared between both arms. RESULTS: Baseline patient-related characteristics were comparable between the arms except for primary site of tumour. No significant differences were noted in acute toxicities between the arms except for fatigue which was statistically higher for control arm. No significant differences in 2-year late toxicities were observed. The median follow-up duration was 25.5 (range, 1.8-39.9) months. The 2-year PFS was 53.3% and 80.0% (p = 0.028) for control and study arm, respectively. The 2-year OS was 60.0% and 86.7% (p = 0.020) in control and study arms, respectively. Multivariate analysis showed clinical stage and site to be significant predictors for OS and PFS, respectively. CONCLUSIONS: The SMART boost technique can be a feasible alternative fractionation schedule that reduces the overall treatment time, maintaining comparable toxicity and survival compared with SIB-IMRT.