Prognostic significance of the age factor in the thyroid cancer: statistical analysis

To determine whether thyroid carcinoma in elderly patients presents any peculiar characteristics, whether the greater biological aggressiveness of the neoplasm modifies the surgical treatment selected, and whether age greater than 70 years represents an independent prognostic factor.

Retrospective analysis of case histories from the Department of Surgery of "La Sapienza" University of Rome; 403 patients subjected to total thyroidectomy between 1993 and 1999, with a minimum follow-up period of 3 years subdivided into three groups: group I (patients aged between 20 and 50 years), group II (patients aged between 51 and 70 years) and group III (patients aged >70 years). The surgical and postoperative treatment is uniform in all study groups.

Age greater than 70 years entails a significant increase in mortality; the mortality rate in the three groups was found to be 3%, 9% and 54%, respectively. Prognosis is significantly worse in the elderly patients group (group III) than in group I (P < or = 0.001) and in group II (P < or = 0.001); group II mortality was significantly higher than that of group I (P = 0.005); in group III, the neoplasm displays features of greater biological aggressiveness (greater incidence of undifferentiated forms, presence of lymph nodes at diagnosis and vascular invasion, locally advanced forms, greater incidence of stage IV).

Statistical analysis shows that the greater biological aggressiveness of the neoplasm in elderly patients worsens the prognosis, although an age exceeding 70 years itself represents an unfavourable prognostic factor; total thyroidectomy does not present any counter-indications in elderly patients.