Intensity-modulated radiation therapy reduces late salivary toxicity without compromising tumor control in patients with oropharyngeal carcinoma: a comparison with conventional techniques.
OBJECTIVE
Intensity-modulated radiation therapy (IMRT) offers superior dosimetric conformity for normal tissue sparing in patients with oropharyngeal cancer. In this study, acute and late toxicity, and tumor control were compared between conventional beam arrangement (CRT) and IMRT.


METHODS
Between January 1970 and December 1999, 430 patients with carcinoma of the oropharynx were treated at the Mallinckrodt Institute of Radiology. There were 260 patients with tonsil primary tumors and 170 patients with tumors arising from the base of the tongue. Twenty-four (6%) patients had stage I disease, 88 (20%) had stage II, 128 (30%) had stage III, and 190 (44%) had stage IV disease. Patients were divided into five treatment groups. Group I consisted of 109 patients who received preoperative CRT. Group II consisted of 142 patients who received postoperative CRT. Group III consisted of 153 patients who received definitive CRT. Inverse planning IMRT (Peacock, NOMOS) was used to treat 14 patients postoperatively (Group IV) and 12 patients definitively without surgery (Group V). Acute and late normal tissue side-effects were scored according to the Radiation Therapy Oncology Group radiation morbidity criteria. The median follow-up was 3.9 years.


RESULTS
The 2-year local-regional control values for the five studied groups were 78, 76, 68, 100 and 88%, respectively. The 2-year disease-free survival values for the five studied groups were 68, 74, 58, 92 and 80%, respectively. IMRT significantly reduced the incidence of late xerostomia.


CONCLUSIONS
When IMRT was compared with conventional techniques, the dosimetric advantage of IMRT did translate into a significant reduction of late salivary toxicity in patients with oropharyngeal carcinoma. No adverse impact on tumor control and disease-free survival was observed in patients treated with IMRT.
Chao
K S
KS
Department of Radiation Oncology, Washington University Medical Center, St. Louis, MO, USA. chao@radonc.wustl.edu
Majhail
N
N
Huang
C J
CJ
Simpson
J R
JR
Perez
C A
CA
Haughey
B
B
Spector
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D014062:Tongue Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D014067:Tonsillar Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D014987:Xerostomia / Q000517:prevention & control*