[Therapy concept in differentiated thyroid gland carcinoma--results of 25 years with 257 patients].

BACKGROUND: Differentiated thyroid carcinoma is a unique tumour in that a low risk-patient population with a tumour-related death rate of near 0% can be found. Yet in these patients the risk and risk factors of curable recurrences must be considered. The question therefore arises, whether in defined subgroups of low risk-patients a reduced extent of treatment (hemithyroidectomy, total thyroidectomy without 131I ablation) may result in cure without recurrence, including low morbidity of treatment and reduced costs.

STUDY DESIGN: In a consecutive series of 257 patients suffering from papillary (146) or follicular (111) carcinomas operated by one surgeon over a period of 25 years, a reduced extent of treatment was carried out essentially in subgroups of minimally invasive follicular carcinoma, namely in pT1,2-tumors of young patients, or in those with capsular invasion alone, and in pT1,2 N0 papillary tumors, representing a subgroup of TNM stage I and II tumors. For N-staging selective lymphadenectomy was carried out at the beginning of the study, but elective lymphadenectomy was used since 1996 for papillary carcinoma. Follow-up was 1-25 (mean = 8) years. All excised tumors were examined by one pathologist.

RESULTS: 167 (approximately 2/3) of the patients presented with a single nodule, whereas in 1/3 a concomitant benign nodular goiter or an immunothyropathy was found. The percentage of grossly invasive follicular carcinoma decreased during the 25 year period from 41 to 10% of all patients (p < 0.0005), whereas the percentage of papillary cancer rise from 35% to 66% (p < 0.005). Hemithyroidectomy, total thyroidectomy without, and with 131I ablation respectively, were performed in 32%, 24%, and 44% of patients. In papillary carcinoma N1-status was found in 21 (23%)/ 92 patients with selective, and in 18/54 patients (33%) with elective lymphadenectomy, respectively (n.s.). One (0.4%) patient died postoperatively. Permanent hypoparathyroidism occurred in 1.9% (3% for total thyroidectomy), permanent recurrent nerve lesion in 1.6% of patients (1% of nerves at risk). PAPILLARY CARCINOMA: No tumour-related death and no serious recurrence occurred in the low risk-group (TNM stages I and II) (n = 112 (84%)), including a T4-, N1-, M1-status in 9%, 20% and 3% of patients, respectively. 4/112 patients (3.6%) developed a recurrence (3 nodal, 1 contralateral, following 131I ablation in 2 instances). Only one (1%) instance of a nodal recurrence occurred in N0-tumors (n = 97). In TNM stages III and IV (high risk) patients (with T4-, N1-, M1-status in 79%, 58%, and 8% respectively), residual and recurrent disease occurred in 7 (33%) patients, leading to 6 (29%) tumor-related deaths. Follicular carcinoma: One 74-year old patient (1.6%) died from minimally invasive follicular carcinoma (n = 54 (51%); mean age 48 years). In 44 (81%) patients treatment did not include remnant ablation. 7 (13%) patients died from widely invasive follicular carcinoma (n = 53 (49%); mean age 64 years) and 3 (6%) further patients are alive with a serious recurrence. No curable recurrence was observed in follicular carcinoma.

CONCLUSIONS: The decrease in goiter endemicity during the last decades in Switzerland paralleled a decrease in the incidence of grossly invasive follicular carcinoma over the 25 year period of the study. Following selective treatment, low risk TNM stage I and II-patients with papillary carcinoma had a tumor-related death rate of 0% and a low (3.6%) recurrence rate. N1-status represents a risk factor for nodal recurrence (even with remnant ablation). Elective vs. selective lymphadenectomy lead to slight stage migration but it presented no advantage in terms of recurrence and death which were rare events. No death occurred in the subgroups of minimally invasive follicular carcinoma of young (< 45) patients (41%) and in the patients without vascular invasion (28%), even without remnant ablation in most instances. No curable recurrence occurred in foll