Implant-supported prosthetic rehabilitation after jaws reconstruction for malignancies of the oral cavity

S60 -

Posters group B was administered five fractions per week, 2 Gy per fraction, up to 60-66 Gy radiation schedule. Chemotherapy starts on the first day of RT. Therapeutic protocol consists of 5 days 5FU venous infusion x 600 mg/m 2 and cis-Platinum x 1O0 mg/m 2 on 6th day. Results:Survival estimation is done by Kaplan-Meier method. Group A - 39 dead, 13 survived. Group B - 40 dead, 12 alive. According to the Log Rank test, no significant difference appears (p=0.9) in the two groups concerning the 5-years overall survival-23.0 % versus 26.9%. In both groups the total tumor control reflects in better survival 44% against 8 % in partial tumor control (p=0.002). Conclusions: Radiotherapy is the prevailing method chosen in locally advanced or nonresectable head and neck carcinomas notwithstanding the late results of 23-25%. Hypo fractionated radiation schedule is a curative management and is an alternative method with similar toxicity to the combined RT/CT in Ioco advanced neck and head tumors. Therefore further improvement of hypofractiona~ tion schemes should be sought in order to consolidate on the favorable early results. 165 poster IDENTIFYING DOSIMETRIC PREDICTORS OF SWALLOWING DYSFUNCTION IN HEAD AND NECK CANCER PATIENTSTREATED WITH IMRT N. Ohri ~,W.L. Thorstad 1, B. Nussenbaum 2,D.R. Adkins ~,I.M. El Naqa ~, B. H. Haughey2,J.O. Deasy~

clinical factors predicting each of the four toxicity outcomes. Results: 16 patients (25%) received MBS evaluations following the initiation of RT. 11 patients (17%) demonstrated aspiration on MBS. 17 patients (27%) had G-tubes in place one year following RT initiation. 11 patients (17%) received late pharyngeal toxicity scores of 2 or higher. The V40, V45, VSO, V55, and V60 of the PC were the only dosimetric parameters that demonstrated significant correlation with all four clinical outcomes on univariate analysis. Gender, chemotherapy, and surgery were not significantly correlated with any of the four toxicity outcomes. Age at the onset of RT correlated with late pharyngeal toxicity scores, and follow-up time correlated with MBS evaluation. On multivariate logistic regression analysis using each of the four toxicity outcomes, the V60 of the PC most frequently emerged as the most predictive factor of swallowing dysfunction. Laryngeal dosimetric variables and clinical parameters such as use of chemotherapy or surgery were not significant predictors of toxicity in the multivariate analyses. Conclusions: Radiation dose to the pharyngeal constrictor muscles was the most significant predictive factor for each indicator of swallowing dysfunction. While adequate dosimetric coverage of the planning target volume remains the primary goal of RT planning, the addition of parameters to limit irradiation on the pharyngeal constrictor muscles may decrease the incidence of swallowing dysfunction as a complication of RT. 166 poster

/WASHINGTONUNIVERSITYSCHOOLOFMEDICINE,Department of Radiation On-

tology, St. Louis,MO, USA, ZWASH~NGTONUNIVERSITYSCHOOLOF MEDICtNE,Department of Otolaryngol-

ogy, St. Louis,MO, USA,

IMPLANT-SUPPORTED PROSTHETIC REHABILITATION AFTER JAWS RECONSTRUCTION FOR MALIGNANCIES OF THE ORAL CAVITY M. Turco, M. Di Cosola, M. Petruzzi

~VASHINGTONUNIVERSITYSCHOOLOFMEOIONE,Department of Medical Oncol-

AZIENDAOSPEDAUERAPOLICLINICODI BARbDepartment of Odontostomatol-

ogy, St. Louis, MO, USA

ogy and Surgery, Bari, Italy

Purpose/Objective: Swallowing dysfunction is a common complication of radiotherapy (RT) for head and neck cancer. Previous studies have suggested that this toxicity may be related to the irradiation of the larynx and pharyngeal constrictor muscles (PC). Our aim was to determine if the dose delivered to these structures is predictive of swallowing dysfunction in relation to other clinical and treatmentrelated factors. Materials/Methods: Dose-volume information was gathered for 64 patients receiving either postoperative or definitive intensity-modulated RT for head and neck cancer at our institution with at least one year of follow-up. All patients were treated to doses of 60-70 Gy (median 66 Gy) delivered in single daily fractions of 2.0-2.2 Gy (median 2.0 Gy). 35 patients (55%) received chemotherapy, either before RT or concurrently. Patient records were also reviewed for modified barium swallow (MBS) evaluations, gastric feeding tube (G-tube) insertions and removals, and late pharyngeal toxicity scores. Median follow-up was 18.2 months (12.2-35.7). Four indicators of swallowing dysfunction were followed: (1) MBS evaluation performed after the initiation of RT, considered indicative of subjective dysphagia; (2) finding of aspiration on any MBS evaluation performed after the initiation of RT; (3) use of G-tube for feeding 1 year following RT initiation; (4) RTOG late pharyngeal toxicity score of 2 or higher. To determine the importance of irradiation of the larynx and PC, contours of those structures were added to the original treatment plans and dose-volume information was calculated. Spearman's rank correlation was used to measure the univariate association of each of the four indicators of swallowing dysfunction with Vx, where V represents the fraction of volume receiving the dose x (in Gray) or greater, for both the larynx and PC. Clinical parameters, including patient age, gender, use of chemotherapy, use of surgery, and duration of follow-up were also included in the univariate analysis. Step-wise logistic regression analysis with statistical resampling validation was then used to determine the statistically significant dosimetric and

Purpose/Objective: Surgical resections of mandible or maxilla for malignancies of the oral cavity heavily (greatly) affect masticatory functions, aesthetics and impair patients' social life. Primary reconstruciotn of bony support and soft tissue coverage becomes mandatory and free tissue transfer techniques offer undeniable advantages. Moreover, implant-supported prosthetic rehabilitation in reconstructed patients represents a major goal. Materials/Methods: From 2001 and 2005, we selected a group of 17 patients treated for malignancies of the oral cavity (12 squamous cell carcinomas, 2 odontogenic malignant tumours, 2 salivary malignant tumours, 1 sarcoma). Seven maxillectomies were performed and primarily reconstructed using 5 fibula osteo-muscular free flaps and 2 DCIA osteo-muscular free flap, while 11 mandibular defects required harvesting 6 fibula osteo-muscular free flaps and 5 DCIA osteo-muscular free flap. Ten patients (squamous cell carcinoma) underwent radiotherapy after surgery. All patients received endosseus implants and muco-gingival surgery. Within 1-1,5 years after primary surgery all were able to wear an implant-supported dental prosthesis. Results: The follow-up period ranged from 1 to 6 years. A total of 75 endosseus implants were placed, 2 of which were lost during the follow-up, leading to a survival implant rate of 97,4%. The resonance frequency analysis (Osstell TM device) and the damping capacity evaluation (Periotest TM device) were used to assess implants stability after loading. Measures results indicated complete implant osteointegration with great stability in the long time. All the patients were able to resume a normal diet and speech articulation and considerably improved their facial aesthetic appearance and social life. Conclusions: Oral rehabilitation using implants inserted in osseus free flaps, namely fibula and lilac crest, represents a reliable method to restore the masticatory function and facial appearance in patients with oro-facial defects following ablative surgery.