Pattern of failure after helical tomotherapy in head and neck cancer.
OBJECTIVE
Helical tomotherapy (HT, Hi-Art TomoTherapy(®)) is a recently developed radiation device delivering highly conformal dose with a rotational gantry resulting in more uniform target doses and better avoidance of organs at risk. Treatment failure patterns in head and neck cancer (HNC) patients treated with HT were analyzed.


METHODS
63 patients with a biopsy-proven HNC were treated with HT. In patients with locoregional failure, the volume of failure (Vf) was contoured and co-registered with the initial planning computed tomography scan. With the use of dose-volume histogram (DVH) analysis, the Vf was classified as "in-field" (InF), "marginal" (MF) or "outside-field" (OutF), if ≥ 95%, 20-94%, and < 20% of Vf, respectively, were within the 95% isodose.


RESULTS
Median follow-up time was 25 months (95% confidence interval 19.4-28 months). 2-year overall survival, disease-free survival, and locoregional control were 66%, 54%, and 77%, respectively. 13 patients developed a locoregional failure (four local, eight regional, and one local and regional). After DVH analysis, there were ten InF and two MF recurrences as well as one OutF recurrence.


CONCLUSIONS
Target delineation and coverage were adequate. The majority of locoregional failures were InF, i.e., in the high-dose region. Future work on dose escalation to the highest risk regions is recommended.
Farrag
Ashraf
A
Department of Radiation Oncology, Oncologic Center UZ Brussel, Brussels, Belgium. drashraffarrag@yahoo.com
Voordeckers
Mia
M
Tournel
Koen
K
De Coninck
Peter
P
Storme
Guy
G
D001706:Biopsy; D003131:Combined Modality Therapy; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods; D015996:Survival Rate; D013997:Time Factors; D017211:Treatment Failure
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