Positron emission tomography in staging and surveillance of oral and oropharyngeal squamous cell carcinoma

PhD ceremony: Mr. C.A. Krabbe, 14.45 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: Positron emission tomography in staging and surveillance of oral and oropharyngeal squamous cell carcinoma

Promotor(s): prof. J.L.N. Roodenburg, prof. P.U. Dijkstra

Faculty: Medical Sciences

This thesis studies the role of the imaging technique “Positron Emission Tomography” (PET) in the diagnostic process of patients with a common kind of mouth and throat cancer: squamous cell carcinoma of the oral cavity and oropharynx (OOSCC). Staging OOSCC correctly is of utmost importance, because the tumor stage at the time of the diagnosis determines both patients treatment and prognosis.

PET with radiolabeled sugar (¹⁸F-FDG) can be used to visualize the extent of the cancer.

From this thesis can be concluded that ¹⁸F-FDG PET can be interpreted reliably in OOSCC. ¹⁸F-FDG PET is particularly apt to detect distant metastases and cancer elsewhere in the body. Lymph node metastases in the neck can also be detected by ¹⁸F-FDG PET. However, just like in conventional imaging, the detection of small lymph node metastases remains difficult.

A disadvantage of ¹⁸F-FDG PET is the fact that increased ¹⁸F-FDG uptake is not specific for malignant tissue, possibly leading to false positive results. As an alternative, radiolabeled amino-acids, like ¹¹C-TYR, were introduced. ¹¹C-TYR PET seems however not suitable to detect cervical metastases. To decrease the chance of false positive PET results, the combination of PET/CT can be used in stead of PET only.

After treatment of OOSCC, the risk of cancer recurrence or developing new cancer remains increased. Early detection of this cancer is of importance for the success of possible treatment. ¹⁸F-FDG PET appears to detect this cancer earlier than the usual clinical investigation does.