Treatment of Cancer of the Base of the Tongue and Glosso-Epiglottic Region: A Multicenter Italian Survey

Large Discrepancies between Planned and Actually Delivere dose in Imrt of Head and Neck Cancer. A Case Report

The case is reported of a patient with locally recurrent carcinoma of the tongue treated with intensity-modulated radiotherapy (IMRT) (simultaneous integrated boost) plus concurrent chemotherapy, who during the third week of radiotherapy developed grade 3 mucositis. Treatment was interrupted for 10 days until significant resolution of the symptoms. At the time of treatment resumption the patient showed 8% weight loss, and in vivo portal dose verification revealed large discrepancies between the computed and measured doses. A new CT scan showed marked tumor shrinkage and modifications to the critical structures. The comparison between the original plan and the hybrid IMRT showed a minimal dose increase in the new target volumes and a marked dose increase in the organs at risk.

This case confirms the need for a robust quality assurance program when using IMRT, the feasibility and efficacy of in vivo dosimetry to detect significant discrepancies between planned and delivered dose, and the need to combine IMRT with 4-dimensional radiotherapy, at least for head and neck cancer.

Treatment results for 84 patients with base of tongue cancer

CONCLUSIONS

For T2 tumors, surgery was indicated if functional preservation was possible. For T3/T4 tumors, the rate of primary disease control was not high and surgery frequently involved total laryngectomy. Points that surgeons must heed when performing such surgery were delineated.

OBJECTIVES

Because tumors originating from the base of the tongue are rare, few large-scale studies of such tumors have been performed. We reviewed treatments and outcomes at our department to establish effective future therapeutic plans.

PATIENTS AND METHODS

From 1971 to 2000, 84 patients with previously untreated and resectable squamous cell carcinoma of the base of the tongue were treated at the Head and Neck Department of the Cancer Institute Hospital, Tokyo. Treatment selection and results were investigated.

RESULTS

The main treatment options were radiotherapy for primary lesions < or = T2 and surgery for primary lesions > or = T3. Overall disease-specific 5-year cumulative survival rate was 59.8%, but there was no significant difference in survival rate at each stage between the two treatments. Among patients who died of the primary disease, the area that was most difficult to control was the superior margin of the lateral wall of the oropharynx (n=7). The incidence of contralateral or retropharyngeal lymph node metastasis was low if tumors neither crossed the midline nor infiltrated the lateral wall. While total laryngectomy was performed on 48 patients, the larynx was operatively preserved in 5 T3 patients and one T4 patient.