Radiotherapy for glottic T1N0 carcinoma with slight hypofractionation and standard overall treatment time: importance of overall treatment time.
OBJECTIVE
We retrospectively investigated treatment outcomes in patients with glottic T1 carcinoma treated with 65 Gy in 26 fractions four times a week and discuss the importance of the overall treatment time.


METHODS
Two hundred one patients with glottic T1 carcinoma were evaluated. Sixty-five Gray in 26 fractions were delivered for 200 patients, whereas 1 patient received 62.5 Gy in 25 fractions. We delivered radiotherapy once daily four times a week in this period, for a weekly dose of 10 Gy. Weekdays except Wednesday were treatment days.


RESULTS
The overall survival rate was 96.8 ± 1.3% (standard error) at 3 years and 90.8 ± 2.2% at 5 years. The local control rate was 91.9 ± 2.0% at 3 years and 89.8 ± 2.3% at 5 years. In patients with an overall treatment time equal to or longer than 47 days, the local control rate was 82.6 ± 6.0% at both 3 and 5 years. In the patients with overall treatment time equal to or less than 46 days, the local control rate was 94.6 ± 1.9% at 3 years and 91.8 ± 2.4% at 5 years. There was a significant difference between these two groups (P = 0.0349). A severe late radiation reaction occurred in one patient. He experienced severe laryngeal edema that required tracheotomy at 6 months after the completion of radiotherapy. The tracheotomy was closed at 14 months after completion of radiotherapy.


CONCLUSIONS
Overall treatment time seems to be an important factor for a good local control rate for glottic T1N0 carcinoma even when treated with slight hypofractionation.
Onimaru
Rikiya
R
Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan. ronimaru@pop.med.hokudai.ac.jp
Hasegawa
Masakazu
M
Yasuda
Kouichi
K
Homma
Akihiro
A
Oridate
Nobuhiko
N
Fukuda
Satoshi
S
Shirato
Hiroki
H
D000328:Adult; D000368:Aged; D019583:Dose Fractionation, Radiation; D005260:Female; D005931:Glottis / Q000473:pathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D007822:Laryngeal Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome