Staging of base of tongue carcinoma by computed tomography

Computed Tomography of the Submandibular Salivary Glands

Computed tomography offers a convenient method for the evaluation of the submandibular salivary glands and their surroundings. Normal measurements were established based on 38 normal subjects. The visualization of the ductal system in the gland and the relationship of the gland to the platysma muscle were recorded. The CT scans of 12 patients with a tongue base carcinoma and 4 patients with a verified obstruction of the submandibular duct were also reviewed to establish how the glands are affected by extrinsic lesions. The normal glands measured 28×18 mm (±5 mm) in the axial plane. Two patients with unilateral hypoplasia of the gland were found in the normal group. Visualization of the intraglandular duct is not a specific finding since it was observed in more than 25 per cent of the normal group. Displacement and bulging of the platysma muscle by the submandibular gland can be a sign of glandular enlargement. It was also seen in 9 out of 12 patients with carcinoma of the base of the tongue.

Staging of squamous cell carcinoma of the oral cavity and oropharynx: a comparison of MRI and CT in T- and N-staging

PURPOSE

Our purpose was to assess the accuracy of CT and MRI in staging of squamous cell carcinoma (SCC) of the oral cavity and oropharynx.

METHOD

Fifty-one episodes of primary and recurrent SCC were assessed with CT and MRI. The results were compared with pathological staging.

RESULTS

For staging primary tumours, the accuracy of MR was 77% and that of CT was 67%. For detecting recurrent tumour, the accuracy of MR was 89% and that of CT was 100%. For N-staging, nodal sites were divided, according to the site of the primary tumour, into high and low risk. Sensitivity for high risk sites was 60% for clinical assessment, 35% for CT, and 75% for MR. Negative predictive value (NPV) was < or = 50% for all methods. For low risk sites, the NPV was > or = 95% for all methods.

CONCLUSION

For T-staging, MR scanning is overall more accurate than CT. If degraded images and T1 tumours are excluded, the techniques are comparable. MR scanning is oversensitive for recurrent disease. For N-staging, all methods failed to detect small metastatic deposits.

Validation and clinical application of computer-combined computed tomography and positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose head and neck images

BACKGROUND

Positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose (PET-FDG) improves the detection of head and neck squamous cell cancer (HNSCC), but lacks anatomical detail. The accuracy of registered computed tomography/magnetic resonance (CT/MR) and PET-FDG in delineation of HNSCC at the primary site and its clinical application was investigated.

METHOD

Preoperatively 30 patients were staged clinically and each had either CT (23), MR (5), or both CT and MR (2) scans, as well as CT/MR-PET-FDG registration. Tumor margins or infiltration of specific anatomical landmarks on the different scans were compared and judged against histology.

RESULTS

For primary tumors CT-PET-FDG (97%) and MR-PET-FDG (100%) delineated the tumor more accurately than CT (69%) or MR (40%) alone. Similarly, CT-PET-FDG (98%) and MR-PET-FDG (100%) were better than CT (70%) and MR alone (80%) in identifying tumor invasion of specific anatomical structures. Management was altered in 7 of 30 patients. The registered images were particularly useful in delineating tumor extension in the infratemporal fossa, maxilla and mandible, and identifying recurrences obscured by scar tissue.

CONCLUSIONS

It is possible to accurately register CT, MR, and PET-FDG data sets in the head and neck. The initial results show that registered CT/ MR-PET-FDG images provide additional clinically relevant information over that obtained from clinical evaluation or conventional CT/MR imaging.

Treatment selection for base of tongue carcinoma

Sixty-two previously untreated patients with squamous cell carcinoma of the base of tongue were retrospectively analyzed. The American Joint Committee on Cancer (AJCC) Stage distribution was I-3, II-7, III-24, and IV-28. The choice of treatment was nonrandomized. The local control was 10/18 with high-dose preoperative radiation, 17/30 with external beam radiation only, and 4/14 with external beam plus interstitial implantation. The median survival for the three treatment regimens were 63, 51, and 13 months, respectively. Preoperative radiation is suggested for tumors with inferior (laryngeal) spread or those with extensive superior extension (to tonsillar fossa and beyond). For centrally placed lesions in the base of the tongue (with or without lateral hypopharyngeal wall spread), radiation alone is recommended. An interstitial implantation should be restricted to lesions equal to or less than 4 x 3 x 2.5 cm3. Since this insertion is technically more demanding than for tumors of the mobile tongue, they should be performed by the more experienced brachytherapist.