Single Vocal Cord Irradiation: Image Guided Intensity Modulated Hypofractionated Radiation Therapy for T1a Glottic Cancer: Early Clinical Results.
OBJECTIVE
To report, from a retrospective analysis of prospectively collected data, on the feasibility, outcome, toxicity, and voice-handicap index (VHI) of patients with T1a glottic cancer treated by a novel intensity modulated radiation therapy technique developed at our institution to treat only the involved vocal cord: single vocal cord irradiation (SVCI).


METHODS
Thirty patients with T1a glottic cancer were treated by means of SVCI. Dose prescription was set to 16 × 3.63 Gy (total dose 58.08 Gy). The clinical target volume was the entire vocal cord. Setup verification was done by means of an online correction protocol using cone beam computed tomography. Data for voice quality assessment were collected prospectively at baseline, end of treatment, and 4, 6, and 12 weeks and 6, 12, and 18 months after treatment using VHI questionnaires.


RESULTS
After a median follow-up of 30 months (range, 7-50 months), the 2-year local control and overall survival rates were 100% and 90% because no single local recurrence was reported and 3 patients died because of comorbidity. All patients have completed the intended treatment schedule; no treatment interruptions and no grade 3 acute toxicity were reported. Grade 2 acute dermatitis or dysphagia was reported in only 5 patients (17%). No serious late toxicity was reported; only 1 patient developed temporary grade 2 laryngeal edema, and responded to a short-course of corticosteroid. The VHI improved significantly, from 33.5 at baseline to 9.5 and 10 at 6 weeks and 18 months, respectively (P<.001). The control group, treated to the whole larynx, had comparable local control rates (92.2% vs 100%, P=.24) but more acute toxicity (66% vs 17%, P<.0001) and higher VHI scores (23.8 and 16.7 at 6 weeks and 18 months, respectively, P<.0001).


CONCLUSIONS
Single vocal cord irradiation is feasible and resulted in maximal local control rate at 2 years. The deterioration in VHI scores was slight and temporary and subsequently improved to normal levels. Long-term follow-up is needed to consolidate these promising results.
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: a.almamgani@nki.nl.
Abrahim
A
Al-Mamgani
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Stefan L S
SL
Kwa
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Lisa
L
Tans
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Michael
M
Moring
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Dennie
D
Fransen
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Robert
R
Mehilal
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Gerda M
GM
Verduijn
Department of Otolaryngology and Head and Neck Surgery - Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Rob J
RJ
Baatenburg de Jong
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Ben J M
BJ
Heijmen
Department of Radiation Oncology - Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Peter C
PC
Levendag
D000368:Aged; D000369:Aged, 80 and over; D054893:Cone-Beam Computed Tomography; D005240:Feasibility Studies; D005260:Female; D005931:Glottis; D006801:Humans; D007822:Laryngeal Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D000069473:Radiation Dose Hypofractionation; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D015996:Survival Rate; D014827:Vocal Cords / Q000000981:diagnostic imaging / Q000528:radiation effects*; D014832:Voice Disorders / Q000209:etiology; D014833:Voice Quality / Q000528:radiation effects