Assessment of treatment response after chemoradiation of head and neck cancer.

Accurate early diagnosis and staging is an essential step in the management of recurrent head and neck cancer. Nevertheless, the diagnosis and staging of recurrent head and neck cancer previously treated by radiation therapy often combined with chemotherapy, remains a challenge. The differentiation between radiation induced reaction and recurrent cancer is a difficult clinical and radiological problem. It is clear that timely diagnosis in case of residual or recurrent tumor is of great importance to increase the possibility of cure. A variety of interventions such as office clinical examinations, blood tests, serum tumor marker measurements, imaging studies and endoscopies are being used to follow-up these patients. No single intervention proved to be absolute or complete in being simultaneously sensitive, specific, inexpensive, safe and efficient at detecting suspected recurrence of head and neck cancer, particularly after chemoradiation. In addition to that, there is no clear evidence of what surveillance regimen or frequency is considered the most adequate or effective in this setting. In this article, we analyze the diagnostic difficulties of tumor recurrence after combined treatment with chemotherapy plus radiation therapy and review the role of clinical, endoscopic and imaging techniques in the follow-up of these patients.