Ciência e terapia do câncer

Intensity Modulated Radiation Therapy (IMRT) in the Treatment of Squamous Carcinoma of the Oropharynx: An Overview

Abstract

Sourav Guha, Charles G Kelly, Rajdeep Guha, Rimpa Achari, Indranil Mallick, Vinidh Paleri, Alastair J Munro and Sanjoy Chatterjee

Background: Intensity Modulated Radiotherapy (IMRT) is being used increasingly for the radical treatment of oropharyngeal cancers. We have reviewed the evidence and summarised the data to enable readers to decide whether the dosimetric advantages of IMRT have been translated into clinical benefit in oropharyngeal cancer treatment.

Methods: We searched Medline and the Cochrane library for published studies investigating the role of IMRT in reducing rates of xerostomia, osteoradionecrosis and difficulties with swallowing.

Results: Despite heterogeneity in the assessment of xerostomia following radiotherapy, 20 out of the 22 studies reported lower xerostomia rates following parotid-sparing IMRT. There is only limited information on the consequences of sparing dose to the submandibular gland and emerging clinical information on the benefits of reducing dose to the pharyngeal constrictor muscles. Rates of osteoradionecrosis are lower with IMRT.

Conclusion: Rates of xerostomia are lower with IMRT than with conventional radiotherapy techniques. Prospective evaluation of IMRT techniques to assess whether lower doses to the submandibular glands and constrictor muscles are associated with clinical benefit is essential. Although there appear to be lower rates of osteonecrosis with IMRT, pre treatment evaluation of dental status and maintenance of dental hygiene remain important.