Radiotherapy often comprises two phases, in which irradiation of a volume at risk for microscopic disease is followed by a sequential dose escalation to a smaller volume either at a higher risk for microscopic disease or containing only gross disease. This technique is difficult to implement with intensity modulated radiotherapy, as the tolerance doses of critical structures must be respected over the sum of the two plans. Techniques that include an integrated boost have been proposed to address this problem. However, clinical experience with such techniques is limited, and many clinicians are uncomfortable prescribing nonconventional fractionation schemes. To solve this problem, we developed an optimization technique that simultaneously generates sequential initial and boost IMRT plans. We have developed an optimization tool that uses a commercial treatment planning system (TPS) and a high level programming language for technical computing. The tool uses the TPS to calculate the dose deposition coefficients (DDCs) for optimization. The DDCs were imported into external software and the treatment ports duplicated to create the boost plan. The initial, boost, and tolerance doses were specified and used to construct cost functions. The initial and boost plans were optimized simultaneously using a gradient search technique. Following optimization, the fluence maps were exported to the TPS for dose calculation. Seven patients treated using sequential techniques were selected from our clinical database. The initial and boost plans used to treat these patients were developed independently of each other by dividing the tolerance doses proportionally between the initial and boost plans and then iteratively optimizing the plans until a summation that met the treatment goals was obtained. We used the simultaneous optimization technique to generate plans that met the original planning goals. The coverage of the initial and boost target volumes in the simultaneously optimized plans was equivalent to the independently optimized plans actually used for treatment. Tolerance doses of the critical structures were respected for the plan sum; however, the dose to critical structures for the individual initial and boost plans was different between the simultaneously optimized and the independently optimized plans. In conclusion, we have demonstrated a method for optimization of initial and boost plans that treat volume reductions using the same dose per fraction. The method is efficient, as it avoids the iterative approach necessitated by currently available TPSs, and is generalizable to more than two treatment phases. Comparison with clinical plans developed independently suggests that current manual techniques for planning sequential treatments may be suboptimal.

5582 Background: Cyclo-oxygenase 2 (COX2) inhibitors have shown promise as radio- and chemosensitizers. We conducted a phase IB/II study to evaluate the toxicity and efficacy of celecoxib, a selective COX2 inhibitor, administered concurrently with carboplatin, paclitaxel, and radiation for locally advanced or recurrent head and neck cancer. Methods: Patients with stage III/IV or recurrent squamous cell carcinoma of the oropharynx, oral cavity, hypopharynx, or larynx were eligible. Primary endpoints were toxicity, local control and survival. Patients were treated with weekly carboplatin (AUC = 2.0), paclitaxel (30 mg/m2) and concurrent radiation (70 Gy). Celecoxib (400 mg bid) was started 1 week prior to the initiation of radiotherapy and was given for a total of 2 years. In 12/04, the study closed due to concerns of cardiotoxicity with COX-2 inhibitors. Celecoxib was discontinued in all patients. The study restarted in 5/06 with the modification that celecoxib would be given only during radiation. Results: Between 12/02 and 1/06, a total of 28 patients were enrolled: 89% were male, median age was 56.5, 3 with recurrent cancer and 25 treated definitively. Five patients have been treated on the modified study. Grade 3/4 toxicities include: mucositis (35% G3), dermatitis (18% G3; 7% G4), febrile neutropenia (21% G3; 3% G4), dysphagia (57% G3), nausea/vomiting (29% G3). Thirty percent did not complete prescribed chemotherapy due to myelosuppression. Acturarial 2 year outcomes in the 20 evaluable, definitively treated patients: 65% survival, 76% local control. Conclusions: Compared to published data using carbo/taxol and RT, an unexpectantly high incident of febrile neutropenia was observed but no increase in radiation dermatitis or mucositis. Two year survival data is comparable to published data. No significant financial relationships to disclose.

Historically, patients with resectable stage III and IV tumors were treated with combined surgery and radiation. Early attempts at improving results by incorporating chemotherapy in the postoperative setting have been largely unsuccessful or inconsistent. However, longer follow-up of recent landmark trials exploring concurrent chemotherapy and radiotherapy have clarified the issue, supporting concurrent cisplatin based chemotherapy for high risk patients. The survival benefit seen in the concurrent chemoradiotherapy trials appears to stem from improved locoregional control, as no reduction in systemic failure has been observed. Another evolving approach to post-operative head and neck radiotherapy is the use of altered fractionation schedules. There are several recent studies exploring either hyperfractionated or accelerated radiotherapy, as a response to the issue of accelerated tumor repopulation, providing evidence that such treatment is beneficial in selected patients. There are several questions worthy of further clinical research, and these will likely continue to follow the lead of nonsurgically managed head and neck cancer. Preliminary data suggests that IMRT can be tailored to postoperative patients, and target volumes defined such that morbidity can be minimized without jeopardizing tumor control. Biological modifiers of radiotherapy may allow selective radiosensitization without the morbidity of concurrent chemotherapy.

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