Head and neck cancer radiotherapy

Conventional treatment uses two opposing lateral fields to encompass the primary lesion and bilateral cervical draining lymph nodes.

Fields include the anterior low neck and both supraclavicular areas.

Fields are reduced to protect the spinal cord and unaffected tissues.

Causes xerostomia and dysphagia.

Intensity modulated radiotherapy (IMRT) has improved the management of cancer of the head and neck.

Intensity modulated radiotherapy (IMRT) provides superior target coverage compared to traditional techniques.

Intensity modulated radiotherapy (IMRT) provides greater than 90% local control, even in advanced lesions.

Intensity modulated radiotherapy (IMRT) gains may be do to technical improvements in imaging techniques delineating tumor volumes, rather than to the radiation method of dose delivery.

Intensity modulated radiotherapy (IMRT) in base of skull tumors, sinus tumors and nasopharyngeal cancers have better results than with conventional radiation.

Conventional radiotherapy given daily provides 70-95% local control and 50% overall survival for patients with early stage I/II head and neck disease.

Conventional daily radiation therapy provides local control to 20-50% and overall survival of less than 10-25% for advanced stage III-IV disease.

Currently reserved a single therapy for early or favorable intermediate stage laryngeal or oropharyngeal primary disease or for patients who have poor performance status with locally advanced disease and who are not candidates for surgery or concurrent chemoradiation treatment.

Limited field treatment can control greater than 90% of stage T1 glottic laryngeal cancers and up to 80% of T2 lesions.

Radiation can locally control 85% of oropharyngeal cancers and provide a 77% disease specific 5 year survival for stage I/II lesions.

Can provide 5 year local control for tonsillar disease up to 75-85% of cases for T1-3 lesions, but only 60% for T4 cancers, while disease specific survival is greater than 60% for stage I-IVa disease but only 20% for stage IVb lesions.

Five year local control for base of tongue cancers is 81-96% for T1-T3 disease, but only 38% for T4 primary lesions treated with head and neck radiation therapy.

Base of tongue lesion have a disease specific survival of 75-100% for stage I-III lesions and 52-56% for stage IVa/b disease.

In a review of 299 patients (Gardner) with oropharyngeal cancer treated with radiation alone for T1-T2 lesions with stage III-IV disease the 5 year local control rate was 90% with a disease free survival of 70% and an overall survival of 65% indicating that radiation is adequate for local control but the addition of chemotherapy is needed to improve systemic disease control and overall survival.

RTOG study 90-03 phase III trial compared once daily radiation therapy with multiple daily small treatments throughout treatment and increased daily fractions during the final weeks of treatment in 1073 patients with stage II-IV disease of the oropharynx, supraglottic larynx, oral cavity and hypopharynx: results indicated that altered fractionation improved locoregional control 54% vs. 46%, 38% vs. 32% 2 year disease free survival with similar overall survival in all 3 groups.

Conclusion of RTOG 90-03 study is that once daily radiation is no longer standard of care for patients receiving radiation alone for stage II-IV disease at the above sites.

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