title: Treatment results of post-operative radiotherapy in patients with salivary duct carcinoma of the major salivary glands.
abstract: OBJECTIVE
  Salivary duct carcinoma (SDC) is a rare malignancy of high-grade pathological type. We evaluated clinical outcomes and prognostic factors in 35 patients with SDC treated post-operatively with adjuvant radiation.
  
  
  METHODS
  We retrospectively assessed overall survival, locoregional control and disease-free survival in 35 patients with SDC of the major salivary glands who underwent surgery and were subsequently treated with radiotherapy. The evaluated prognostic factors included gender, age, symptom duration, tumour site, tumour size, TNM classification, and the following pathological features: perineural invasion, lymphovascular invasion, extraparenchymal invasion and resection-margin status.
  
  
  RESULTS
  Of the 35 patients, 30 (85.7%) were male. Median age at initial diagnosis was 62 years (range 38-75 years). The parotid gland was the main site affected in 22 patients (62.9%). 18 patients (51.5%) had pathological T3/T4 tumours, and 26 (74.3%) showed pathological nodal involvement. Actuarial 5-year locoregional control, disease-free survival and overall survival rates were 63.3%, 47.4% and 55.1%, respectively. The cause-specific death rate was 31.4% (n=11). Pathological nodal involvement was correlated with distant metastasis (p=0.011). Lymphovascular invasion was significantly prognostic for distant metastasis-free survival (p=0.049), locoregional control (p=0.012) and overall survival (p=0.003) in a Cox proportional hazard model, whereas perineural invasion was only significantly prognostic for overall survival (p=0.005).
  
  
  CONCLUSIONS
  Surgery and post-operative radiotherapy were effective for locoregional control. Lymphovascular invasion and perineural invasion were significant prognostic factors in patients with SDC.
authors.affiliation: Department of Radiation Oncology, Bundang CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea.
authors.forename: J Y
authors.initials: JY
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: K-J
authors.initials: KJ
authors.lastname: Cho
authors.forename: S Y
authors.initials: SY
authors.lastname: Kim
authors.forename: S Y
authors.initials: SY
authors.lastname: Nam
authors.forename: S-H
authors.initials: SH
authors.lastname: Choi
authors.forename: J-L
authors.initials: JL
authors.lastname: Roh
authors.forename: E K
authors.initials: EK
authors.lastname: Choi
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
authors.forename: S Y
authors.initials: SY
authors.lastname: Song
authors.forename: H S
authors.initials: HS
authors.lastname: Shin
authors.forename: S-K
authors.initials: SK
authors.lastname: Chang
authors.forename: S D
authors.initials: SD
authors.lastname: Ahn
mesh_terms: D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D009364:Neoplasm Recurrence, Local / Q000209:etiology; D011182:Postoperative Care / Q000379:methods*; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D012468:Salivary Gland Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D016896:Treatment Outcome