LOCALLY INVASIVE PAPILLARY THYROID-CARCINOMA - 1940-1990

Well-differentiated thyroid carcinoma infrequently invades the upper a erodigestive tract. However, when invasion occurs, it is the source of significant morbidity. The most common structures invaded by thyroid carcinoma are the recurrent laryngeal nerves, larynx, pharynx, and eso phagus. Invasion of these structures produces symptoms of airway insuf ficiency, dysphagia, and hemoptysis. This study was designed to define more clearly the significance of invasion of papillary thyroid carcin oma on survival. At the Mayo Clinic, 262 patients treated for invasive papillary thyroid carcinoma between 1940 and 1990 were retrospectivel y evaluated. In this group the sites of invasion were muscle 53%, trac hea 37%, laryngeal nerve 47%, esophagus 21%, larynx 12%, and other sit es 30%. Complete tumor removal was accomplished in 56% of cases. Kapla n-Meier survival curves were calculated for the population. The overal l survival was 790/. at 5 years, 63% at 10 years, and 54% at 15 years. When the Cox proportional hazard model was applied to the survival da ta, the factors that had significant influence on survival were invasi on of the trachea and the esophagus. Completeness of resection approac hed statistical significance. Muscle invasion, laryngeal invasion, and recurrent laryngeal nerve invasion had no significant independent inf luence on survival. These data suggest that when papillary thyroid car cinoma extends beyond the thyroid capsule and invades adjacent structu res, the site invaded will influence survival. Survival may be improve d in those cases in which complete surgical excision of the tumor is p erformed.