Radical external beam reirradiation of recurrent head and neck cancer

Recurrent head and neck carcinomas represent a therapeutic challenge for the surgeons as well as for the treating radiation oncologists. Despite advances in the treatment of newly dia-gnosed head and neck carcinomas, relapses occur very frequently and contribute significantly to patient mortality. External beam reirradiation is still considered to be a controversial therapeutic intervention. Historically, in the era of 2- and 3-dimensional conformal radiotherapy, its narrow therapeutic ratio has long led to a general concern that the potential benefit could not sufficiently outweigh the high risk associated with the treatment. The unfavorable therapeutic ratio, however, could be positively influenced by the use of modern techniques of intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), stereotactic body radiation therapy (SBRT) and heavy-ion radiotherapy (protons, carbon ions).

The purpose of this review is to create a practical tool for clinical decision-making on the type of patient suitable for reirradiation and the exact type of radiotherapy technique with respect to its expected therapeutic effect, toxicity profile and availability throughout the institutions. In the introductory section, selection of patients is defined with an emphasis on factors that significantly affect overall survival and may be particularly useful in shared decision-making approach within multidisciplinary teams. Furthermore, the text deals with the individual types of external beam radiotherapy techniques (IMRT, SBRT, heavy-ion radiotherapy) with a clear summary of therapeutic outcomes and toxicity from published scientific evidence that had a significant impact on clinical practice.