Outcomes and prognostic factors for surgery followed by modern radiation therapy in parotid gland carcinomas.
OBJECTIVE
To evaluate the outcomes and prognostic factors in patients with parotid gland cancers treated with adjuvant radiotherapy with or without chemotherapy.


METHODS
Eighty-five patients with parotid gland cancers were identified between October 2001 and September 2011. The median radiation dose was 66 Gy (range, 9-76 Gy). The outcomes assessment included overall survival, locoregional control, distant metastasis-free survival and disease-free survival.


RESULTS
The stage distribution was 20 patients  (23.5%) in stage I, 28 (32.9%) stage II, 14 (16.5%) stage III and 23 (27.1%) stage IV. Fifty-five patients (64.7%) had positive margins and 23 patients (27.1%) had close margins (<0.5 cm). Lymph node extracapsular spreading occurred in nine patients. The adjuvant therapy included radiotherapy alone in 47 patients (55.3%) and concurrent chemoradiotherapy in 38 patients (44.7%). With a median follow-up of 4.5 years (range, 0.4-11 years), the 5-year overall survival, locoregional control, distant metastasis-free survival and disease-free survival were 82.0, 88.4, 82.4 and 77.5%, respectively. Based on multivariate analysis, N1/N2 was a significant negative prognostic factor for distant metastasis-free survival, disease-free survival and overall survival. Perineural invasion was a significant negative prognostic factor for locoregional control, distant metastasis-free survival and disease-free survival. Patients 50 years or older had significantly worse distant metastasis-free survival, disease-free survival and overall survival.


CONCLUSIONS
Surgery and radiotherapy treatment could achieve excellent outcomes in a modern cohort. However, N1/N2, perineural invasion and age ≥50 years, but not positive margins, are significant factors associated with a worse prognosis.
Department of Radiation Oncology, Chang Gung Memorial Hospital, Taoyuan, Taiwan Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan Graduate Institute of Clinical Medical Science, Chang Gung University, Taoyuan.
Bing-Shen
BS
Huang
Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital, Taipei Cancer Research Center, National Taiwan University College of Medicine, Taipei Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei.
Wan-Yu
WY
Chen
Department of Radiation Oncology, Chang Gung Memorial Hospital, Taoyuan, Taiwan Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan.
Cheng-En
CE
Hsieh
Department of Radiation Oncology, Chang Gung Memorial Hospital, Taoyuan, Taiwan Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan.
Chien-Yu
CY
Lin
Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan Department of Pathology, Chang Gung Memorial Hospital, Taoyuan.
Li-Yu
LY
Lee
Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan Graduate Institute of Clinical Medical Science, Chang Gung University, Taoyuan Department of Otorhinolaryngology, Chang Gung Memorial Hospital, Taoyuan.
Ku-Hao
KH
Fang
Department of Radiation Oncology, Chang Gung Memorial Hospital, Taoyuan, Taiwan Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan.
Ngan-Ming
NM
Tsang
Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan Department of Otorhinolaryngology, Chang Gung Memorial Hospital, Taoyuan.
Chung-Jan
CJ
Kang
Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan Division of Hematology/Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan.
Hung-Ming
HM
Wang
Department of Radiation Oncology, Chang Gung Memorial Hospital, Taoyuan, Taiwan Head and Neck Oncology Group, Chang Gung Memorial Hospital, Taoyuan jtchang@adm.cgmh.org.tw.
Joseph Tung-Chieh
JT
Chang
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy; D002945:Cisplatin / Q000627:therapeutic use; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D005720:Gamma Rays / Q000627:therapeutic use*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D010307:Parotid Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
D002945:Cisplatin
head and neck; radiation therapy; salivary gland cancer