A prognostic index for predicting lymph node metastasis in minor salivary gland cancer.
OBJECTIVE
Large studies examining the clinical and pathological factors associated with nodal metastasis in minor salivary gland cancer are lacking in the literature.


METHODS
Using the Surveillance, Epidemiology, and End Results (SEER) database, we identified 2,667 minor salivary gland cancers with known lymph node status from 1988 to 2004. Univariate and multivariate analyses were conducted to identify factors associated with the use of neck dissection, the use of external beam radiation therapy, and the presence of cervical lymph node metastases.


RESULTS
Four hundred twenty-six (16.0%) patients had neck nodal involvement. Factors associated with neck nodal involvement on univariate analysis included increasing age, male sex, increasing tumor size, high tumor grade, T3-T4 stage, adenocarcinoma or mucoepidermoid carcinomas, and pharyngeal site of primary malignancy. On multivariate analysis, four statistically significant factors were identified, including male sex, T3-T4 stage, pharyngeal site of primary malignancy, and high-grade adenocarcinoma or high-grade mucoepidermoid carcinomas. The proportions (and 95% confidence intervals) of patients with lymph node involvement for those with 0, 1, 2, 3, and 4 of these prognostic factors were 0.02 (0.01-0.03), 0.09 (0.07-0.11), 0.17 (0.14-0.21), 0.41 (0.33-0.49), and 0.70 (0.54-0.85), respectively. Grade was a significant predictor of metastasis for adenocarcinoma and mucoepidermoid carcinoma but not for adenoid cystic carcinoma.


CONCLUSIONS
A prognostic index using the four clinicopathological factors listed here can effectively differentiate patients into risk groups of nodal metastasis. The precision of this index is subject to the limitations of SEER data and should be validated in further clinical studies.
Lloyd
Shane
S
Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520-8040, USA.
Yu
James B
JB
Ross
Douglas A
DA
Wilson
Lynn D
LD
Decker
Roy H
RH
D000230:Adenocarcinoma / Q000473:pathology / Q000556:secondary*; D000367:Age Factors; D000704:Analysis of Variance; D018267:Carcinoma, Acinar Cell / Q000473:pathology / Q000556:secondary; D003528:Carcinoma, Adenoid Cystic / Q000473:pathology / Q000556:secondary; D018277:Carcinoma, Mucoepidermoid / Q000473:pathology / Q000556:secondary; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007822:Laryngeal Neoplasms / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology; D009333:Neck; D037981:Neck Dissection; D009367:Neoplasm Staging; D009669:Nose Neoplasms / Q000473:pathology; D010610:Pharyngeal Neoplasms / Q000473:pathology; D011379:Prognosis; D018426:SEER Program; D012468:Salivary Gland Neoplasms / Q000473:pathology*; D012470:Salivary Glands, Minor / Q000473:pathology*; D012737:Sex Factors; D047368:Tumor Burden