The pattern of failure after reirradiation of recurrent squamous cell head and neck cancer: implications for defining the targets.
OBJECTIVE
Reirradiation (re-RT) of recurrent head and neck cancer (HNC) may achieve long-term disease control in some patients, at the expense of high rates of late sequelae. Limiting the re-RT targets to the recurrent gross tumor volume (rGTV) would reduce the volumes of reirradiated tissues; however, its effect on tumor recurrence pattern is unknown.


METHODS
This is a retrospective review of 66 patients who underwent curative-intent re-RT for nonresectable recurrent or second primary mucosal squamous cell HNC. Treatment was delivered with three-dimensional conformal (3D) RT or intensity-modulated RT (IMRT). The targets in all patients consisted of the rGTVs with tight (0.5-cm) margins, with no intent to treat prophylactically lymph nodes or subclinical disease in the vicinity of the rGTVs. The sites of locoregional failures (LRFs) were determined using imaging at the time of failure and were compared with the rGTVs.


RESULTS
Median re-RT dose was 68 Gy. Forty-seven patients (71%) received concomitant chemotherapy, and 31 (47%) received hyperfractionated, accelerated RT. At a median follow-up of 42 months, 16 (23%) were alive and disease-free. Fifty patients (77%) had a third recurrence or persistent disease, including 47 LRFs. All LRFs occurred within the rGTVs except for two (4%) (95% confidence interval, 0-11%). Nineteen patients (29%) had Grade > or = 3 late complications, mostly dysphagia (12 patients).


CONCLUSIONS
Almost all LRFs occurred within the reirradiated rGTVs despite avoiding prophylactic RT of tissue at risk of subclinical disease. These results support confining the re-RT targets to the rGTVs to reduce reirradiated tissue volumes.
Popovtzer
Aron
A
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
Gluck
Iris
I
Chepeha
Douglas B
DB
Teknos
Theodoros N
TN
Moyer
Jeffrey S
JS
Prince
Mark E
ME
Bradford
Carol R
CR
Eisbruch
Avraham
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods; D019233:Retreatment / Q000009:adverse effects; D012189:Retrospective Studies; D017211:Treatment Failure; D047368:Tumor Burden; D055815:Young Adult