Arm 1 Standard Fractionation (SFX): 70 Gy / 35 fractions /7weeks R N plus cisplatin: 100 mg/m2 on days 1, 22, and 43

Arm 2  Accelerated Fractionation by Concomitant Boost (AFX-CB): I M 72 Gy/42 fractions /6 weeks plus cisplatin: 100 mg/m2 on days 1 and 22

Target Volume and Dose Fractionation

6.1.1 Target Volume: The initial target volume will have a 2-3 cm margin around gross primary and nodal disease. The boost portals will have a 1-1.5 cm margin around gross disease.

6.1.2 Standard Fractionation: Radiation (to both the initial target volume encompassing the gross and subclinical disease sites and the boost volume covering the primary tumor and involved nodes) will be delivered in 2 Gy per fraction, five fractions a week. The primary tumor and clinically/radiologically involved nodes will receive 70 Gy in 7 weeks and uninvolved nodes will receive 50 Gy in 5 weeks. The anterior lower neck field will be treated with 2 Gy per fraction at 3-cm depth to a total dose of 50 Gy.

6.1.3 Concomitant Boost Regimen: Radiation to the initial target volume encompassing the gross and subclinical disease sites will be delivered in 1.8 Gy per fraction, five fractions a week to 54 Gy in 30 fractions over 6 weeks. At 32.4 Gy/18 Fx (i.e., latter part of week 4) , the boost volume covering gross tumor and clinically/radiologically involved nodes will receive boost irradiation of 1.5 Gy/Fx as second daily fraction (at least 6 h interval) for a total of 12 treatment days (18 Gy total). All treatment times must be documented on the treatment record.

The primary tumor and clinically/radiologically involved nodes will receive 72 Gy in 42 fractions over 6 weeks and uninvolved nodes will receive 54 Gy in 6 weeks. Clinically/radiologically negative posterior neck should receive a minimum dose of 50.4 Gy at 3 cm. The anterior lower neck field will be treated with 1.8 Gy per fraction at 3-cm depth to a total dose of 50.4 Gy in 28 fractions in 5.6 weeks.

6.1.4 Technique: Radiotherapy will commence with opposed lateral portals for the primary tumor and upper nodes and a matching anterior field for the lower neck and supraclavicular fossa. The anterior field should match the lateral fields on the skin, and should have an appropriate method to avoid overlap on the spinal cord at the junction of the fields. The inferior border of the anterior field will be 1 cm below the clavicles.

A portal reduction off the spinal cord will be made to limit the spinal cord dose to < 45 Gy in all arms. Therefore, to supplement the dose to the posterior neck and clinically positive nodes, boost techniques may include an additional electron beam of proper energy to the posterior neck, wedge pair or oblique fields.