Diagnostics using perfusion CT imaging to determine the extent of bone marrow involvement of the mandible by squamous cell carcinoma - a pilot study

Squamous cell carcinoma (SCC) is the most common malignant oral cavity tumor
with approximately 800 new cases every year in the Netherlands. Treatment of
SCC adjacent or fixed to the mandible is (wide) surgical excision resection in
continuity with the affected bone. Continuity of the mandible may be maintained
(marginal resection) or disrupted (segmental resection). Marginal resection is
in general sufficient, if there is no or only limited bone marrow involvement.
Loss of mandibular continuity may cause functional, aesthetic and social
problems when the mandible is not reconstructed. Immediate reconstruction of
the mandible, most often with a free vascularized bone flap, is the treatment
of choice. These operations are time consuming, require a two-team approach and
demand a long postoperative hospital stay. Postoperative histopathologic
findings show that high percentages of the resected mandibles (35-78%) do not
demonstrate signs of bone marrow involvement. This emphasizes the lack of
reliable screening imaging techniques. There are several imaging techniques
that have the ability to visualise tumor ingrowth in the mandible. Up till now
often a combination of imaging techniques is used to accurately predict bone
invasion. It nevertheless remains difficult to demonstrate the extent of bone
marrow invasion in the mandible. Perfusion CT imaging can possibly demonstrate
the extension of bone marrow invasion in the mandible by squamous cell
carcinoma. Perfusion CT imaging has been used in the past to differentiate
benign from malignant head and neck lesions, to predict and measure the effect
of chemotherapy and to quantify neoplastic microcirculation.

To demonstrate the extent of bone marrow invasion of the mandible by SCC. Can
perfusion CT imaging demonstrate the extent of bone marrow invasion of the
mandible by SCC? If so, it can prevent unnecessary resection of the mandible.

An observational study.

The burden for participants in this study is negligible. Extra CT images are
made prior to the conventional head and neck CT, but in the same session. This
will take place during a hospital stay as part of the preoperative screening.
The risks associated with participation are possibly the extra bolus of
contrast agent and the longer scanning procedure. This means a higher radiation
dose. The higher radiation dose, however, is negligible in comparison with the
radiation dose of the postoperative radiation therapy, which is indicated in
almost all patients with bone marrow involvement.