Long-term outcomes after external beam irradiation and brachytherapy boost for base-of-tongue cancers.
OBJECTIVE
To assess long-term efficacy and toxicity associated with external beam irradiation (EBRT) and interstitial (192)Ir implantation for the treatment of squamous carcinoma of the base of tongue.


METHODS
Between April 1975 and December 1993, 41 patients with base-of-tongue carcinomas were treated with (192)Ir interstitial implants after EBRT at Stanford University. One patient had Stage I, 6 had Stage II, 7 had Stage III, and 27 had Stage IV tumors. Twenty-eight patients had cervical lymph node involvement at diagnosis. All received EBRT to a median dose of 50 Gy (range 48.9-68 Gy) to the primary tumor and regional lymph nodes before brachytherapy. Interstitial implant was performed 2-4 weeks after EBRT. Intraoperatively, nylon catheters were placed via steel trocars into the base of tongue, glossotonsillar groove, and pharyngo-epiglottic fold using a catheter looping technique. Twenty-three of 28 node-positive patients also underwent simultaneous neck dissections. Postoperatively, the (192)Ir seeds were inserted and allowed to remain in place for approximately 35 h to achieve a median tumor dose of 26 Gy (range 20-34 Gy) to a median volume of 73 cc. Survival, local control, and complications were assessed.


RESULTS
With a median follow-up of 62 months (range 9-215) for all patients and 90 months for alive patients, the 5-year Kaplan-Meier survival estimate was 66%. The 5-year local control rate was 82%, with 7 patients recurring locally, 2 of whom were salvaged with surgery. Nodal control was achieved in 93% of patients with either EBRT alone or in combination with neck dissection. The 5-year freedom from distant metastasis rate was 83%. Acute complications included transient bleeding (5%) and infection (8%). Late complication included soft-tissue necrosis/ulceration (7%), osteoradionecrosis (5%), and xerostomia.


CONCLUSIONS
Base-of-tongue carcinoma can be effectively treated with EBRT and (192)Ir implant boost. Local control is excellent and complication rates are acceptable.
Gibbs
Iris C
IC
Department of Radiation Oncology, Stanford University, Stanford, CA 94305-5302, USA. iris.gibbs@stanford.edu
Le
Quynh-Thu
QT
Shah
Rachit D
RD
Terris
David J
DJ
Fee
Willard E
WE
Goffinet
Don R
DR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011878:Radiotherapy / Q000379:methods; D016019:Survival Analysis; D014062:Tongue Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D017211:Treatment Failure
D007496:Iridium Radioisotopes