Prognostic Factors in Mortality and Morbidity in Patients with differentiated Thyroid Cancer

Abstract

We attempted to determine if women younger than 45 years of age who have isolated papillary thyroid cancer and whose tumors are smaller than 4 cm (T2N0M0) are at low risk for mortality and morbidity following thyroid lobectomy. To this end, we analyzed information on both women and men obtained from our review of the literature, and we integrated it with data compiled in the Delaware Cancer Registry. We performed a secondary analysis to determine if the risk of death and recurrence can be predicted on the basis of age, tumor size, sex, histology, and the type of operation. We found that among patients who had undergone either thyroid lobectomy or total thyroidectomy, mortality rates were 1.3% for those younger than 45 years of age and 15.6% for those 45 years and older (p< 0.0001). With respect to tumor size, patients whose masses were smaller than 4 cm had significantly lower mortality (3.0%) and recurrence (11.1%) rates than did those whose tumors were 4 cm or larger (16.8 and 33.3%, respectively; p< 0.0001). Other significant risk factors for death were male sex and the presence of follicular thyroid cancer (as opposed to papillary thyroid cancer). The risk of permanent hypocalcemia was significant among patients who had undergone total thyroidectomy, but not among those who had been treated with lobectomy. The subgroup of patients who had the lowest risk of mortality and morbidity was made up of women younger than 45 years who had a papillary thyroid tumor smaller than 4 cm that was limited to one lobe and who had undergone lobectomy. On the other hand, we found that lobectomy might carry a higher risk of recurrence (from a micrometastasis in the cervical lymph node) than does total thyroidectomy. Experienced surgeons whose rates of hypocalcemia and recurrent laryngeal nerve paralysis following total thyroidectomy are low offer their patients the unambiguous advantage of superior follow-up with thyroglobulin and radioactive iodine.