title: Postoperative intensity-modulated radiotherapy for squamous cell carcinoma of the external auditory canal and middle ear: treatment outcomes, marginal misses, and perspective on target delineation.
abstract: OBJECTIVE
  To report outcomes of the rare disease of squamous cell carcinoma (SCC) of the external auditory canal (EAC) and middle ear treated with surgery and postoperative intensity-modulated radiotherapy (IMRT). Failure patterns related to spatial dose distribution were also analyzed to provide insight into target delineation.
  
  
  METHODS
  A retrospective review was conducted of the records of 11 consecutive patients with SCC of the EAC and middle ear who were treated with curative surgery and postoperative IMRT at one institution between January 2007 and February 2010. The prescribed IMRT dose was 60 to 66 Gy at 2 Gy per fraction. Three patients also received concurrent cisplatin-based chemotherapy, and 1 patient received concurrent oral tegafur/uracil. The median follow-up time was 19 months (range, 6-33 months).
  
  
  RESULTS
  Four patients had locoregional recurrence, yielding an estimated 2-year locoregional control rate of 70.7%. Among them, 1 patient had persistent disease after treatment, and 3 had marginal recurrence. Distant metastasis occurred in 1 patient after extensive locoregional recurrence, yielding an estimated 2-year distant control rate of 85.7%. The estimated 2-year overall survival was 67.5%. The three cases of marginal recurrence were near the preauricular space and glenoid fossa of the temporomandibular joint, adjacent to the apex of the ear canal and glenoid fossa of the temporomandibular joint, and in the postauricular subcutaneous area and ipsilateral parotid nodes, respectively.
  
  
  CONCLUSIONS
  Marginal misses should be recognized to improve target delineation. When treating SCC of the EAC and middle ear, care should be taken to cover the glenoid fossa of the temporomandibular joint and periauricular soft tissue. Elective ipsilateral parotid irradiation should be considered. The treatment planning procedure should also be refined to balance subcutaneous soft-tissue dosimetry and toxicity.
authors.affiliation: Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Wan-Yu
authors.initials: WY
authors.lastname: Chen
authors.forename: Sung-Hsin
authors.initials: SH
authors.lastname: Kuo
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Chen
authors.forename: Szu-Huai
authors.initials: SH
authors.lastname: Lu
authors.forename: Chiao-Ling
authors.initials: CL
authors.lastname: Tsai
authors.forename: Jason Chia-Hsien
authors.initials: JC
authors.lastname: Cheng
authors.forename: Ruey-Long
authors.initials: RL
authors.lastname: Hong
authors.forename: Ya-Fang
authors.initials: YF
authors.lastname: Chen
authors.forename: Chuan-Jen
authors.initials: CJ
authors.lastname: Hsu
authors.forename: Kai-Nan
authors.initials: KN
authors.lastname: Lin
authors.forename: Jenq-Yuh
authors.initials: JY
authors.lastname: Ko
authors.forename: Pei-Jen
authors.initials: PJ
authors.lastname: Lou
authors.forename: Cheng-Ping
authors.initials: CP
authors.lastname: Wang
authors.forename: Fok-Ching
authors.initials: FC
authors.lastname: Chong
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary / Q000601:surgery; D004424:Ear Canal; D004428:Ear Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D004432:Ear, Middle; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D011182:Postoperative Care; D061106:Radiotherapy Setup Errors; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D035583:Rare Diseases / Q000532:radiotherapy* / Q000601:surgery; D016896:Treatment Outcome