title: Brachytherapy for early oral tongue cancer: low dose rate to high dose rate.
abstract: To examine the compatibility of low dose rate (LDR) with high dose rate (HDR) brachytherapy, we reviewed 399 patients with early oral tongue cancer (T1-2N0M0) treated solely by brachytherapy at Osaka University Hospital between 1967 and 1999. For patients in the LDR group (n = 341), the treatment sources consisted of Ir-192 pin for 227 patients (1973-1996; irradiated dose, 61-85 Gy; median, 70 Gy), Ra-226 needle for 113 patients (1967-1986; 55-93 Gy; median, 70 Gy). Ra-226 and Ir-192 were combined for one patient. Ir-192 HDR (microSelectron-HDR) was used for 58 patients in the HDR group (1991-present; 48-60 Gy; median, 60 Gy). LDR implantations were performed via oral and HDR via a submental/submandibular approach. The dose rates at the reference point for the LDR group were 0.30 to 0.8 Gy/h, and for the HDR group 1.0 to 3.4 Gy/min. The patients in the HDR group received a total dose of 48-60 Gy (8-10 fractions) during one week. Two fractions were administered per day (at least a 6-h interval). The 3- and 5-year local control rates for patients in the LDR group were 85% and 80%, respectively, and those in the HDR group were both 84%. HDR brachytherapy showed the same lymph-node control rate as did LDR brachytherapy (67% at 5 years). HDR brachytherapy achieved the same locoregional result as did LDR brachytherapy. A converting factor of 0.86 is applicable for HDR in the treatment of early oral tongue cancer.
authors.affiliation: Department of Radiology, Toyonaka Municipal Hospital, Shibahara 4-14-1, Toyonaka, 560-8565 Osaka, Japan. hideya10@hotmail.com
authors.forename: Hideya
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Takehiro
authors.initials: T
authors.lastname: Inoue
authors.forename: Ken
authors.initials: K
authors.lastname: Yoshida
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Souhei
authors.initials: S
authors.lastname: Furukawa
authors.forename: Naoya
authors.initials: N
authors.lastname: Kakimoto
authors.forename: Kimishige
authors.initials: K
authors.lastname: Shimizutani
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Inoue
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis; D014062:Tongue Neoplasms / Q000532:radiotherapy*; D016896:Treatment Outcome