Comparison of the Clinical Outcomes of Patients with Squamous Cell Carcinoma of the Tonsil Receiving Postoperative Ipsilateral Versus Bilateral Neck Radiotherapy: A Propensity Score Matching Analysis (KROG 11-07).
OBJECTIVE
The impact of postoperative ipsilateral neck radiotherapy (INRT) versus bilateral neck radiotherapy (BNRT) on the clinical outcomes of patients with tonsillar squamous cell carcinoma was analyzed retrospectively.


METHODS
Between October 2001 and June 2012, 241 patients with T1-2 and N0-N2b tonsillar carcinoma from 16 institutes underwent postoperative INRT (n=84) or BNRT (n=157) following a tonsillectomy. Seventy patients were identified from each group by propensity score matching and compared in terms of the overall survival (OS), disease-free survival (DFS), locoregional relapse-free survival (LRRFS), and distant metastasis-free survival (DMFS) rates calculated using the Kaplan-Meier method with a log-rank test.


RESULTS
The median follow-up was 55 months (range, 3 to 133 months). The survival outcomes in the INRT and BNRT groups were similar: 5-year OS (92.8% vs. 94.0%, p=0.985), DFS (80.5% vs. 94.2%. p=0.085), LRRFS (88.1% vs. 97.1%, p=0.083), and DMFS (92.7% vs. 97.0%, p=0.370). Subgroup analysis revealed no contralateral neck recurrence in 61 patients with T1-2N0-2a regardless of the treatment groups. For 79 patients with N2b, contralateral neck recurrence was more common in the INRT group than in the BNRT group (7.9% vs. 0.0%), but the difference was not significant (p=0.107). The overall grade ≥ 2 toxicities were lower in the INRT group: acute (45.7% vs. 74.3%, p=0.001) and late (4.3% vs. 31.4%, p < 0.001), respectively.


CONCLUSIONS
INRT is an attractive strategy for patients with T1-2N0-2a tonsillar carcinoma compared to BNRT. For patients with N2b, there was a small risk of contralateral neck recurrence when treated with INRT, but its impact on the OS was limited with successful salvage treatment.
Proton Therapy Center, National Cancer Center, Goyang, Korea.
Youngkyong
Y
Kim
Proton Therapy Center, National Cancer Center, Goyang, Korea.
Kwan Ho
KH
Cho
Proton Therapy Center, National Cancer Center, Goyang, Korea.
Sung Ho
SH
Moon
Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea.
Chang Geol
CG
Lee
Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea.
Ki Chang
KC
Keum
Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Sang-Wook
SW
Lee
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Yong Chan
YC
Ahn
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Dongryul
D
Oh
Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Yeon-Sil
YS
Kim
Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Yong Kyun
YK
Won
Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
Hong-Gyun
HG
Wu
Department of Otolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul, Korea.
J Hun
JH
Hah
Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Korea.
Young-Taek
YT
Oh
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy / Q000009:adverse effects / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011182:Postoperative Care; D057216:Propensity Score; D018714:Radiotherapy, Adjuvant; D016019:Survival Analysis; D014067:Tonsillar Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D014068:Tonsillectomy; D017211:Treatment Failure; D016896:Treatment Outcome
Adjuvant radiotherapy; Ipsilateral neck; Radiation volume; Tonsillar neoplasms; Toxicity