The failure patterns of oral cavity squamous cell carcinoma after intensity-modulated radiotherapy-the university of iowa experience.
OBJECTIVE
Determine the failure patterns of oral cavity squamous cell carcinoma (SCC) treated with intensity-modulated radiotherapy (IMRT).


METHODS
Between May 2001 and July 2005, 55 patients with oral cavity SCC were treated with IMRT for curative intent. Forty-nine received postoperative IMRT, 5 definitive IMRT, and 1 neoadjuvant. Three target volumes were defined (clinical target CTV1, CTV2, and CTV3). The failure patterns were determined by coregistration or comparison of the treatment planning computed tomography to the images obtained at the time of recurrence.


RESULTS
The median follow-up for all patients was 17.1 months (range, 0.27-59.3 months). The median follow-up for living patients was 23.9 months (range, 9.3-59.3 months). Nine patients had locoregional failures: 4 local failures only, 2 regional failures only, and 3 had both local and regional failures. Five patients failed distantly; of these, 3 also had locoregional failures. The 2-year overall survival, disease-specific survival, local recurrence-free survival, locoregional recurrence-free survival, and distant disease-free survival was 68%, 74%, 85%, 82%, and 89%, respectively. The median time from treatment completion to locoregional recurrence was 4.1 months (range, 3.0-12.1 months). Except for 1 patient who failed in contralateral lower neck outside the radiation field, all failed in areas that had received a high dose of radiation. The locoregional control is strongly correlated with extracapsular extension.


CONCLUSIONS
Intensity-modulated RT is effective for oral cavity SCC. Most failures are in-field failures. Further clinical studies are necessary to improve the outcomes of patients with high-risk features, particularly for those with extracapsular extension.
Yao
Min
M
Department of Radiation Oncology, University of Iowa Health Care, Iowa City, IA 52242, USA. min-yao@uiowa.edu
Chang
Kristi
K
Funk
Gerry F
GF
Lu
Heming
H
Tan
Huaming
H
Wacha
Judith
J
Dornfeld
Kenneth J
KJ
Buatti
John M
JM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000401:mortality / Q000532:radiotherapy* / Q000556:secondary; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D009361:Neoplasm Invasiveness; D016609:Neoplasms, Second Primary / Q000000981:diagnostic imaging / Q000209:etiology; D011859:Radiography; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D017211:Treatment Failure