Loco-regional recurrence after surgical treatment of oral squamous cell carcinoma: Proposals for follow-up imaging based on literature, national guidelines and institutional experience.

The recurrence rate following the treatment of oral squamous cell carcinoma (OSCC) by primary surgery is about 10%-26%. The earliest possible diagnosis of residual tumour, recurrence of local tumour disease, and subsequent metastasis is essential for an improvement of the overall survival and of the survival period for affected patients. No international consensus exists for a post-therapeutic surveillance schedule for OSCCs. Based on a review of the literature, existing guidelines, and our institutional experience, we have established an algorithm for the follow-up of these patients regarding the timing and techniques of postoperative imaging. We recommend a follow-up interval of 6 weeks during the first half-year after discharge from hospital by single clinical and alternating clinical check-ups combined with computed tomography (CT) or magnetic resonance imaging (MRI), followed by an interval of 3 months in the second half-year, with clinical and radiological check-ups. In year 2, we recommend a follow-up interval of 3 months with single clinical and alternating clinical check-ups combined with CT or MRI. In year 3, we recommend screening every 6 months, both clinically and via imaging, because of the decreased risk of recurrence. From year 5 onwards, our recommendation is a clinical and imaging-based examination every 6-12 months, depending on patient risk factors and disease progression. Four standard imaging techniques, namely positron emission tomography (PET), CT, MRI, and ultrasound (US), are discussed concerning their range of application, sensitivity, and specificity. Furthermore, the technical aspects of our institutional protocols are described in detail. In highly frequented head and neck cancer centres, PET and US are of secondary importance, since CT and MRI are nowadays highly efficient tools in primary diagnostic and post-therapeutic surveillance.