Patterns of failure and toxicity after intensity-modulated radiotherapy for head and neck cancer.
OBJECTIVE
To determine the outcome of patients treated with intensity-modulated radiotherapy (IMRT) for head and neck cancer.


METHODS
We reviewed the charts of 100 consecutive patients treated with IMRT for squamous cell carcinoma of the oropharynx (64%), nasopharynx (16%), hypopharynx (14%), and larynx (6%). Most patients were treated with a concomitant boost schedule to 72 Gy. Of the 100 patients, 54 (54%) received adjuvant chemotherapy, mostly concurrent cisplatin. The dosimetry plans for patients with either locoregional failure or Grade 4-5 complications were reviewed and fused over the computed tomography images corresponding with the location of the event. Marginal failures were defined as those that occurred at a region of high-dose falloff, where conventional fields would have provided better coverage.


RESULTS
The median follow-up of living patients was 3.1 years (range, 1-5.2 years). The 3-year rate of local control, locoregional control, freedom from relapse, cause-specific survival, and overall survival for all patients was 89%, 87%, 72%, 78%, and 71%, respectively. The 3-year rate of freedom from relapse, cause-specific survival, and overall survival for the 64 oropharynx patients was 86%, 92%, and 84%, respectively. Of the 10 local failures, 2 occurred at the margin of the high-dose planning target volume. Both regional failures occurred within the planning target volume. No locoregional failures occurred outside the planning target volume. Of the 100 patients, 8 and 5 had Grade 4 and 5 complications from treatment, respectively. All patients with Grade 5 complications had received adjuvant chemotherapy. No attempt was made to discriminate between the complications from IMRT and other aspects of the patients' treatment.


CONCLUSIONS
Intensity-modulated radiotherapy did not compromise the outcome compared with what we have achieved with conventional techniques. The 2 cases of recurrence in the high-dose gradient region highlight the potential hazard of approaches that involve highly conformal dose distributions.
Schoenfeld
Gordon O
GO
Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL 32610-0385, USA.
Amdur
Robert J
RJ
Morris
Christopher G
CG
Li
Jonathan G
JG
Hinerman
Russell W
RW
Mendenhall
William M
WM
D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D017024:Chemotherapy, Adjuvant; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D011832:Radiation Injuries / Q000473:pathology; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012189:Retrospective Studies; D017211:Treatment Failure