The prognosis of specific types of salivary gland tumors.

The relative rarity of salivary gland cancers means that there are few follow-up studies based on substantial numbers on which estimates of prognosis of the individual histologic subtypes can be based. In an attempt to overcome this problem 106 reports of follow-up studies were examined. For 52 studies a statistical method was devised to calculate 5-year and 10-year survival rates in uniform fashion. Fifty-four reports, however, had to be discarded either because of inadequacy of the data provided or because certain data essential for statistical analysis was lacking. Sufficient data was available for the estimation of survival rates for 2298 malignant salivary gland tumors of four histologic types. The overall 5-year and 10-year survival rates were found to be as follows: acinic cell carcinoma 82% and 68%, respectively; mucoepidermoid carcinoma 71% and 50%, respectively; adenoid cystic carcinoma 62% and 39%, respectively; malignant mixed tumor 56% and 31%, respectively. Since the great majority (over 70%) of salivary gland tumors are pleomorphic adenomas, and also since complete excision of these tumors presents considerable difficulties, their recurrence-free rate was also estimated and found to be 96.6% after 5 years and 93.2% after 10 years.