S460 I. J. Radiation Oncology d Biology d Physics Volume 69, Number 3, Supplement, 2007

2465 A Dosimetric Evaluation of Markers vs. Bony Anatomy Alignments for a Head and Neck Case

O. A. Zeidan, C. Lee, K. Langen, P. Kupelian, R. Manon, S. Meeks

M.D. Anderson Cancer Center Orlando, Orlando, FL

Purpose/Objective(s): Traditionally bony anatomy alignments have been used for the alignment of head and neck patients. It isevaluated if the implantation of markers in the tumor leads to differences in alignment and doses delivered to the tumor.

Materials/Methods: Two gold markers were implanted in the base-of-tongue of a patient. MegaVoltage CT images were acquiredfor daily image guidance using a Tomotherapy unit for a total of 35 fractions. The MVCT images were retrospectively registeredwith the planning kVCT image set using two methods: (1) marker-based alignments and (2) bony anatomy-based alignments usingthe cervical vertebrae at the level of markers. Figure 1 shows an axial MVCT/kVCT overlay through the relevant anatomy. Dif-ferences in patient alignment were evaluated. Ultimately the dosimetric consequence of each registration method is of interest. Toevaluate the dosimetric consequences a deformable image registration algorithm and a dose recalculation techniques was used.Differences in the daily and cumulative D95 to three separate target volumes (shown in Fig. 1) were scored.

Results: The average ± SD differences between the two registrations methods in the lateral and vertical directions were 2.5 ± 2.1mm (max: 7 mm) and 0.2 ± 1.6 mm (max: 3 mm). In the longitudinal direction the two registration methods were always within 1mm. The daily decrease in the D95 to the three target volumes averaged 1.5 ± 1.3, 0.8 ± 1, and 2.3 ± 4% for the bony anatomyalignments. The respective values for the marker alignments were 1.3 ± 1.1, 0.8 ± 0.9, and 5.1 ± 6.0%. This indicates that fortwo of the three target volumes the systematic decrease and random variation in the delivered target dose is almost identical.In one of the three target volumes the systematic and random decrease in D95 is slightly larger if marker alignments are used.If the cumulative effect after 35 treatment fractions is evaluated the dosimetric decrease in target D95 is smaller, as expected.For the bony anatomy alignments the three cumulative target D95 values decrease by 0.6, 0.3, and 1%. The respective valuesfor the marker alignments were 0.4, 0.2, and 2.5%.

Conclusions: Using two different registration techniques can result in different alignments in the head and neck region. This in-dicates that the implanted markers are mobile (Standard deviation of up to 2 mm) with respect to the bony anatomy. However, bothalignments result in similar dosimetric consequences on a daily and cumulative basis. For one of the three evaluated structuresmarker based alignments result in a slightly larger degrading of the delivered dose with respect to the planned dose.

Author Disclosure: O.A. Zeidan, TomoTherapy Inc., B. Research Grant; C. Lee, TomoTherapy Inc., B. Research Grant; K. Langen,TomoTherapy Inc., B. Research Grant; P. Kupelian, TomoTherapy Inc., B. Research Grant; R. Manon, TomoTherapy Inc.,B. Research Grant; S. Meeks, TomoTherapy Inc., B. Research Grant.

2466 Results for Carcinoma of the Paranasal Sinuses and Nasal Cavity Treated With Intensity Modulated

Radiation Therapy

E. D. Donnelly, W. L. Thorstad, J. O. Deasy, S. A. Fergus, D. Khullar, D. M. MacDonald

Washington University in St. Louis, St. Louis, MO

Purpose/Objectives: To review our institutional experience using intensity-modulated radiation therapy (IMRT) in the treatmentof patients with paranasal sinus and nasal cavity carcinoma.

Methods/Materials: Thirty-seven patients with carcinoma of the paranasal sinus or nasal cavity were treated using IMRT tech-niques at Washington University in St. Louis between May 1998 and January 2006. Median age at diagnosis was 60 years; 70% ofthe patients were male and 30% were female. Disease was stage II in 8.1%, stage III in 5.4%, and stage IV in 86.5%. Fifteen patientshad maxillary sinus primaries, 11 had nasal cavity, 7 had ethmoid sinus, 3 had sphenoid sinus, and 1 had a frontal sinus primary.Histologic type was squamous cell in 48%, sinonasal undifferentiated carcinoma (SNUC) in 14%, esthesioneuroblastoma in 11%,and other in 27%. In addition to radiation therapy, surgery was a component of therapy in 57% of cases, and chemotherapy wasa component in 62% of cases. The Kaplan-Meier method was used to estimate overall survival, disease-specific survival, distantmetastasis-free probability, and locoregional progression-free probability rates.

Results: Follow-up among surviving patients ranged from 7.9 months to 105.3 months (median, 50.7 months). Twenty-one pa-tients were alive at the time of this study; of these, two patients had evidence of disease at last follow-up. The 3-year local tumorcontrol rate and locoregional tumor control rate were 65% and 60%, respectively. Four patients developed isolated distant metas-tasis. The 3-year disease-specific survival and overall survival rates were 67% and 59%, respectively. Acute grade 3+ toxicity wasnoted in 24% of patients. Late toxicity encountered during the study included unilateral blindness (2 patients), cataracts (2 patients),and retinopathy (1 patient) (see Fig.).

Conclusions: Tumors of the paranasal sinuses and nasal cavity are infrequent and pose significant problems due to advanced pre-sentation at the time of diagnosis and proximity to critical structures. Locoregional tumor recurrence remains the predominant

Proceedings of the 49th Annual ASTRO Meeting S461

pattern of failure, similar to our institutional experience with conventional radiation therapy. Dose escalation protocols forparanasal sinus and nasal cavity carcinomas may be warranted.

Author Disclosure: E.D. Donnelly, None; W.L. Thorstad, None; J.O. Deasy, None; S.A. Fergus, None; D. Khullar, None;D.M. MacDonald, None.

2467 Long-Term Results of a Prospective Non-Randomized Multicenter Pilot Study to Preserve the Larynx

Function Using Concomitant Boost Radiochemotherapy With Carboplatin

V. Rudat1, H. Eckel2, P. Volling3, M. Schroder4, S. Staar5, F. Wallner6, A. Dietz7

1Saad Specialist Hospital, Al Khobar, Saudi Arabia, 2Landeskrankenhaus Klagenfurt, Klagenfurt, Austria, 3EvangelischesKrankenhaus Oldenburg, Oldenburg, Germany, 4Staedtisches Krankenhaus Kassel, Kassel, Germany, 5Klinikum Bremen-Mitte,Bremen, Germany, 6University of Heidelberg, Heidelberg, Germany, 7University of Leipzig, Leipzig, Germany

Purpose/Objective(s): This study was undertaken to assess the feasibility of a new larynx preservation protocol.

Materials/Methods: Between 3/1998 and 10/2000 42 patients with moderately advanced cancer of the larynx (n = 17) andhypopharynx (n = 25) were treated in a prospective non-randomized larynx preservation pilot study. The alternative treatmentoption for all patients was a total laryngectomy (LE). The study patients received 66 Gy in 5 weeks using a concomitant boosttechnique and 70 mg/sqm Carboplatin on day 1 to 5 in week 1 and 5. The results were retrospectively compared using a matchedpair technique with 42 patients treated with LE and postoperative radiotherapy in the same institutions.

Results: The median follow-up time of the study patients was 41 months (9–95 months). The 5-year survival was 0.65 (95% CI0.46–0.84), the 5-year locoregional failure-free survival 0.60 (95% CI 0.45–0.75), and the 5-year tracheotomy-free survival 0.67(95% CI 0.48–0.85). Cox multivariate regression analysis showed the total tumor volume to be the only statistically significantfactor on locoregional failure-free survival. The matched pair comparison showed no statistically significant difference to the pa-tients treated with LE regarding survival (p = 0.87) or locoregional failure-free survival (p = 0.23). Five of 23 tumor-free long-termsurvivors with a follow-up of greater than 36 months received a tracheotomy because of severe radiation induced fibrosis 28, 38, 38,71 and 83 months after radiochemotherapy.

Conclusions: This protocol was feasible and appeared to be an acceptable alternative to LE. Long term follow-up is essential tothoroughly assess the value of larynx preservation protocols.

Author Disclosure: V. Rudat, None; H. Eckel, None; P. Volling, None; M. Schroder, None; S. Staar, None; F. Wallner, None;A. Dietz, None.

2468 From Manual to Automatic Contouring in Head and Neck Cancer for Intensity Modulated Radiation

Therapy

H. Abbas1, P. Y. Bondiau2, G. Malandain3, S. El Said1, G. Madelis2, M. Omran1, S. Marcie2, J. P. Gerard2, R. J. Bensadoun2

1South Egypt Cancer Institute, Assiut, Egypt, 2Centre Antoine-Lacassagne, Nice, France, 3INRIA, Sophia-Antipolis, France

Background: It is highly necessary to incorporate image-based technology in modern radiotherapy for head and neck cancer,especially for recent treatment modalities as intensity-modulated radiotherapy, and this necessities standardization of CT-baseddelineation. RTOG guidelines appear to be the most widely accepted for CT-based delineation of the node levels in the node-negative neck. Manual contouring is dependent on the skills of the clinician, and to overcome this dependency, automatic contour-ing is developing to standardize way of contouring and exclude skills of the clinician.

Purpose/Objective(s): To determine feasibility of manual contouring, pitfalls of its practical application, and the validity ofautomatic atlas in contouring of the head and neck region.

Materials/Methods: This study was done on 10 patients (20 neck sides) with head and neck tumors, with clinically node negativeneck for whom radiotherapy was the primary treatment modality. Previous neck radiotherapy and/or surgical neck dissection wereexclusion criteria. CT cuts without contrast for head and neck region were done. First, manual contouring at each CT cut using