title: Longitudinal changes over 2 years in parotid glands of patients treated with preoperative 30-Gy irradiation for oral cancer.
abstract: OBJECTIVE
  To evaluate longitudinal changes in parotid volumes and saliva production over 2 years after 30 Gy irradiation.
  
  
  METHODS
  We retrospectively evaluated 15 assessable patients treated for advanced oral cancer. Eligibility criteria were a pathologic diagnosis of squamous cell carcinoma, preoperative radiation therapy with a total dose of 30 Gy delivered in 15 fractions, and the availability of longitudinal data of morphological assessments by computed tomography and functional assessments with the Saxon test spanning 2 years after radiation therapy. In the Saxon test, saliva production was measured by weighing a folded sterile gauze pad before and after chewing; the low-normal value is 2 g/2 min. Repeated-measures analysis of variance with Bonferroni adjustment for multiple comparisons was used to determine the longitudinal changes.
  
  
  RESULTS
  The normalized ipsilateral parotid volumes 2 weeks and 6-, 12- and 24 months after radiation therapy were found to be 72.5, 63.7, 66.9 and 78.1%, respectively; the normalized contralateral volumes were 69.8, 64.6, 72.2 and 82.0%, respectively. The bilateral parotid volumes were significantly decreased after radiation therapy (P < 0.01). The nadir appeared at 6 months post-radiation therapy and the volumes substantially recuperated 24 months after radiation therapy (P < 0.01). Mean saliva production before radiation therapy was 3.7 g; the longitudinal changes after radiation therapy were 31.3, 38.0, 43.3 and 69.6%, respectively. Substantial recuperation of saliva production was observed 24 months after radiation therapy (P = 0.01).
  
  
  CONCLUSIONS
  Although parotid volumes and saliva production were decreased after 30 Gy irradiation, we observed the recuperation of morphological and functional changes in the parotid glands 2 years after radiation therapy.
authors.affiliation: Department of Radiology, National Hospital Organization Kumamoto Medical Center, Kumamoto, Japan.
authors.forename: Etsushi
authors.initials: E
authors.lastname: Tomitaka
authors.forename: Ryuji
authors.initials: R
authors.lastname: Murakami
authors.forename: Keiko
authors.initials: K
authors.lastname: Teshima
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nomura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakaguchi
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakayama
authors.forename: Mika
authors.initials: M
authors.lastname: Kitajima
authors.forename: Toshinori
authors.initials: T
authors.lastname: Hirai
authors.forename: Yushi
authors.initials: Y
authors.lastname: Araki
authors.forename: Masanori
authors.initials: M
authors.lastname: Shinohara
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000532:radiotherapy* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000532:radiotherapy* / Q000601:surgery; D020360:Neoadjuvant Therapy / Q000379:methods*; D009929:Organ Size / Q000528:radiation effects; D010306:Parotid Gland / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D020127:Recovery of Function; D012189:Retrospective Studies; D012463:Saliva / Q000378:metabolism* / Q000528:radiation effects*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014987:Xerostomia / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology