Changing failure patterns in oropharyngeal squamous cell carcinoma treated with intensity modulated radiotherapy and implications for future research.
OBJECTIVE
Review the University of Iowa experience with intensity modulated radiation treatment (IMRT) in oropharyngeal squamous cell carcinoma.


METHODS
From January 2000 to July 2004, 66 patients with oropharyngeal cancer were treated with IMRT, 62 with definitive IMRT and 4 postoperative IMRT. Three target volumes (CTV1, CTV2, and CTV3) were defined. The prescribed doses to CTV1, CTV2, and CTV3 were 70 to 74 Gy, 60 Gy, and 54 Gy, respectively, for definitive IMRT, and 60 to 66 Gy, 60 Gy, and 54 Gy, respectively, for postoperative IMRT.


RESULTS
Median follow-up was 27.3 months and all living patients had a follow-up of at least 11.5 months. The 3-year estimate of locoregional progression free survival was 98.8%. However, there is a high incidence of distant metastasis with a 3-year estimate of distant metastasis-free survival of 80.4%. In addition, there is a high incidence of second primary tumor. The 3-year overall survival and 3-year disease-free survival were 78.1% and 64.4%, respectively. Treatment was well tolerated with 1 death resulting from treatment toxicity.


CONCLUSIONS
IMRT offers an excellent locoregional control for oropharyngeal cancer patients. Failure patterns have changed with an increased portion of patients who failed distantly, either with metastasis or second primary tumor. Therefore, survival for these patients is still poor. Future research should focus on identifying patients at high risk of distant diseases and developing effective systemic treatment and prevention for distant diseases.
Yao
Min
M
Department of Radiation Oncology, University of Iowa Health Care, Iowa City, IA, USA. min-yao@uiowa.edu
Nguyen
Thanh
T
Buatti
John M
JM
Dornfeld
Kenneth J
KJ
Tan
Huaming
H
Wacha
Judith
J
Bayouth
John E
JE
Clamon
Gerald H
GH
Funk
Gerry F
GF
Smith
Russell B
RB
Chang
Kristi
K
Hoffman
Henry T
HT
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000532:radiotherapy*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D016609:Neoplasms, Second Primary; D009959:Oropharyngeal Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D016896:Treatment Outcome