Clinical prognostic factors in malignant parotid gland tumors.

OBJECTIVE

To analyze the factors in parotid malignant epithelial tumors influencing recurrences and disease-specific survival.

METHODS

We retrospectively reviewed the files of 150 patients treated at our institution, from 1974 to 1998. Twenty-four patients were not treated by surgery and were excluded from this study. The remaining 126 patients were treated with surgery and 74 patients had postoperative radiotherapy. Thirty-three patients were treated with parotidectomy plus neck dissection. Neck lymph node metastasis was found in 22 patients, 5 patients had occult neck metastasis, and 4 periparotid lymph nodes metastasis. The mean age was 49 years old. According to the UICC/1997 TNM Classification, 49 patients were stage I, 27 stage II, 22 stage III, and 28 stage IV. The influence of selected factors on the 10 year disease-specific survival was analyzed using the Kaplan-Meier actuarial method and the log-rank test.

RESULTS

Forty patients had mucoepidermoid carcinoma, 18 patients adenocarcinoma NOS, 18 patients acinic cell carcinoma, 15 patients adenoid cystic carcinoma, 11 patients malignant mixed tumor, 11 patients salivary duct carcinoma, and 13 patients other pathology. Twenty-five patients had recurrences: 17 had local recurrences, 4 patients had neck recurrences, and 4 were loco-regional recurrences. Five factors influenced negatively the prognosis: 1) T stage (p.00001), 2) grade (p.00001), 3) + lymph nodes (p.0007), 4) facial nerve dysfunction (p.0001), and 5) age (p.004). Patients with high-grade tumors and high-stage tumors had the worst prognosis according to the multivariate analysis. The 10-year disease-specific survival was 97% for stage I, 81% for stage II, 56% for stage III, and 20% for stage IV.

CONCLUSION

The grade of the tumor and stage were the most important prognostic factor.

EBM RATING: C.