In this issue, we report on the use of positron emission tomography with fludeoxyglucose F 18 (FDG-PET) for early follow-up scanning of patients with advanced-stage squamous cell carcinoma of the head and neck.1 It is well known that micrometastases are undetectable for imaging tests. During the early disease course, a PET scan may remain negative although the cancer is not entirely eradicated at involved lymph nodes. A residual cancer would only be revealed later on. For the assessment of positive findings seen on PET images, a further clarification using histologic or cytologic studies, or at least an additional imaging test, is usually performed. A negative PET scan finding is controlled by follow-up studies. It seems obvious that a clinical follow-up of 1 year is better as a reference standard than a shorter follow-up time in patients having an early PET scan with negative findings.
Goerres GW, Stoeckli SJ. Imaging Literature and Terminology: When Is It Residual Cancer and When Recurrence?. Arch Otolaryngol Head Neck Surg. 2004;130(1):120-121. doi:10.1001/archotol.130.1.120