Management and outcome of patients with mucoepidermoid carcinoma of major salivary gland origin: a single institution's 30-year experience.

BACKGROUND

Mucoepidermoid carcinoma (MEC) is one of the most frequent epithelial malignancies of the salivary glands. Prediction of clinical outcome of MEC is challenging.

MATERIAL AND METHODS

We retrospectively reviewed 52 cases of MEC of major salivary gland origin diagnosed at the Department of Otolaryngology-Head and Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland, during a 30-year period of 1976 to 2005. Criteria used for diagnosis were those of World Health Organization classifications valid at each time point, and criteria for grading were those recommended by Armed Forces Institute of Pathology fascicle (1996). Since 1993, the degree of cell proliferation was used at our institution as an adjunct tool when grading MEC. The majority of cases occurred in the parotid gland (n = 47, 90%) followed by the submandibular gland (n = 5, 10%).

RESULTS

We had 39% high-grade (HG), 14% intermediate-grade (IMG), and 44% low-grade (LG) MECs. T categories were T1, n = 18; T2, n = 16; T3, n = 9; T4, n = 9. Forty-nine (94%) patients were treated with curative intent. These patients underwent surgery, and 24 (49%) patients received postoperative radiotherapy. Follow-up time varied from 6 months to 9 years. Forty-five percent of HG-MEC patients and 67% of IMG-MEC patients developed locoregional failures or distant metastases during a 3-year follow-up as opposed to none of the LG-MEC patients. Of MEC patients with N0 neck, two HG-MEC patients and one IMG-MEC (8%) patient developed regional recurrence during follow-up.

CONCLUSIONS

Patient outcome in the different grades of MEC suggests a need for overview of the treatment protocol, especially with regard to LG-MEC and IMG-MEC. The apparently unusual occurrence of locoregional failures and metastases in LG-MEC suggests a restrictive approach in surgical management. However, the frequent occurrence of such failures in IMG-MEC warrants an aggressive approach with these tumors.