Multidrug resistance in mucoepidermoid carcinoma of the parotid gland--immunohistochemical investigations of P-glycoprotein expression.

UNLABELLED: Abstract Conclusion: P-glycoprotein is abundantly expressed in certain parotid mucoepidermoid carcinoma tissues, known historically to be multidrug resistant. This discovery may be important in incrementally advancing our ability to develop alternative pharmacologic strategies to improve multi-modality tumor control. OBJECTIVE: P-glycoprotein plays a functional role in promoting the efflux of drug metabolites in certain malignant tumors. With this understanding we immunohistochemically investigated the expression of P-glycoprotein in parotid mucoepidermoid carcinoma tissues and examined prognostic factors that contribute to the treatment of parotid cancer. METHODS: Thirteen patients with mucoepidermoid carcinoma of the parotid gland were included. P-glycoprotein expression was immunohistochemically investigated by a modified avidin-biotin-peroxidase complex method using four different antibodies. RESULTS: P-glycoprotein expression was observed in a higher percentage of patients with higher grade malignancy. The tumor size-related difference in P-glycoprotein expression was only significant for staining with one antibody, and no significant differences were observed with or without induction chemotherapy.

Long-term follow-up and salvage surgery in patients with T2N0M0 squamous cell carcinoma of the glottic larynx following concurrent chemoradiation therapy with cisplatin and 5-fluorouracil for laryngeal preservation.

CONCLUSION: Patients who received concurrent chemoradiation therapy or radiation therapy alone were followed over a long term. The complete response (CR), 10-year survival, and 10-year larynx preservation rates were 87.5%, 95.3%, and 75.1%, respectively. Statistically, concurrent chemoradiation therapy contributes to laryngeal preservation but not to the survival rate. OBJECTIVE: To determine the additive and synergistic effects of anticancer chemotherapy combined with chemoradiation therapy for squamous cell carcinoma (SCC) of the glottic larynx. METHODS: Eighty-nine patients with untreated T2N0M0 SCC of the glottic larynx were included. Thirty-two patients received treatment cycles consisting of intravenous cisplatin (CDDP) on day 1 (80 mg/m(2)) and intravenous 5-fluorouracil (5-FU) over 120 h on days 2-6 (600 mg/m(2)/day) every 4 weeks. Radiotherapy was delivered by a 4 MV linac X-ray machine at a dose of 66 Gy. Fifty-seven patients received radiotherapy alone. RESULTS: After chemoradiation therapy, the overall response, CR, 10-year survival, and 10-year larynx preservation rates were 100%, 87.5%, 95.3%, and 75.1%, respectively. Side effects included leukopenia, neutropenia, mucositis, and dermatitis. Seven patients (21.9%) required salvage surgery. Pathological findings confirmed that the treatment regimen caused marked cancer tissue degeneration. Histologic examination of surgical specimens suggested that the safety margin for partial laryngectomy was 4 mm from the gross tumor.