Surgical treatment of differentiated thyroid carcinoma: a retrospective study

We carried out a retrospective analysis of our experience in the management of Differentiated Thyroid Carcinoma (DTC), in order to better define prognostic factors (age, gender, histological type, stage) and outline a standard procedure, where it's possible, for surgical treatment.

Patient population consisted of 432 cases, operated from 1978 to 2003. We carried out 285 operations of total thyroidectomy of which 39 associated to some kind of lymphadenectomy, 66 totalization (21 pts had been operated in other institutes), 60 subtotal thyroidectomies and 21 lobo-isthmectomies. Survival and mortality curves for age, sex, histological type, grading and staging have been calculated. Kaplan-Meyer statistical elaboration for disease-free interval and Mann-Whitney test for the comparison of different clinical and pathological data have been employed.

The statistical analysis puts in evidence that on 432 cases examined, with a follow-up from 1 to 25 ys (median = 6.33 ys) and with a drop-out of 60 cases (13.8 %), total mortality for cancer has been of 24 cases (6,4%), with a median interval free by disease of 4.2 ys (range 5 months to 25 ys), and a probability to stay free by disease at 12 and 24 months respectively of 95.1% and 91.6%. The median survival is resulted of 5.8 ys (range 1 to 25 ys) with a probability of survival at 24 and 48 months respectively of 97.5% and 94.3%. The multivariate analysis evidences the most important variables, i.e. age > 45 ys, tumor of intermediate malignancy, with size 1.5 cm, operative M+, significantly condition the prognosis, noticeably getting worse it, independently by the kind of carried out operation.

Our present therapeutic choices are: 1. total thyroidectomy in the treatment of the apparently benign pathology when bilaterally with spread; the checking at the final histological exam of a cancer makes however think adequate the carried out operation; 2. lobo-isthmectomy in the treatment of unilateral benign pathology or with suspect FNAB for follicular neoplasm; the histological checking of a cancer makes think the operation adequate only in presence of favourable prognostic parameters, but in presence even of just one unfavourable variable, we consider necessary the totalization; 3. total thyroidectomy in presence of a certain or strongly suspected preoperative diagnosis of cancer.