Surgical treatment for thyroid cancer

External beam radiotherapy for differentiated thyroid cancer

PURPOSE

To evaluate the efficacy of external beam radiation therapy (EBRT) for differentiated thyroid carcinomas.

METHODS

Forty-two patients with a locally advanced or recurrent differentiated thyroid carcinoma received high-dose EBRT. Thirty-three patients had local-regional disease and 9 patients also had asymptomatic disease metastases. Twenty patients (48%) had macroscopic local-regional disease before EBRT.

RESULTS

The 5-year outcomes for the overall population and for the subset of those without distant metastases before EBRT were local-regional control (88% and 89%, respectively), cause-specific survival (80% and 86%, respectively), and overall survival (54% and 60%, respectively). Local-regional control was improved for patients with microscopic residual disease compared with macroscopic disease, those with previously untreated tumors, and for those who received more than 64 Gy.

CONCLUSION

EBRT increases the likelihood of local-regional control for patients with locally advanced differentiated thyroid carcinoma.

Thyroid malignancy in endemic nodular goitres: prevalence, pattern and treatment

AIMS

The epidemiology of thyroid cancers in goitre endemic zones has not been recently reviewed, and changes being currently reported have been from studies in non-endemic areas. The aims of this study were to present the clinical pattern of thyroid malignancy in a goitre endemic area and identify recent changes, if any.

METHODS

The study was conducted at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria between January 1983 and December 1993. Records of patients with nodular goitres treated with thyroidectomy were reviewed, and the clinical features, laboratory parameters, treatment, outcome and follow-up of histologically-proven malignant cases were studied.

RESULTS

Thirty-six of 279 (12.9%) patients, aged 13-85 years (mean)=43.7+/-14.7 years), carried malignant goitres, and most (80%) were young or middle-aged women. Of the well-differentiated cancers, follicular type was the most prevalent, being six- and 12-fold as frequent as papillary and medullary cancers (69%vs 11% and 5.6%), respectively. Lymphoma accounted for 5.6%, fibrosarcoma, 5.6% and anaplastic, 2.8%. No relationship was demonstrable between cancer type, duration of goitre and age at diagnosis (r=0.06 and 0.17, respectively).

CONCLUSIONS

Thyroid cancers afflict comparatively young women in our environment, and follicular cancer remains the predominant type, partly as a result of persisting dietary iodine deficiency.

Extent of surgery for intermediate-risk well-differentiated thyroid cancer

BACKGROUND

Methods of assigning patients with papillary or follicular thyroid cancer (well-differentiated thyroid cancer) to risk groups for the purpose of determining appropriate therapy have been developed. Despite these efforts, the optimal extent of surgery for intermediate-risk patients remains controversial.

METHODS

A retrospective study was conducted of 208 patients with well-differentiated thyroid cancer (DTC) from two institutions. Univariate and multivariate analysis of patient- and tumor-related variables was performed. A regression model was obtained, three risk groups (low, intermediate, and high) were defined, and survival curves were generated.

RESULTS

Prognostic variables were age (P <0.001), distant metastases (P <0.001), tumor size (P <0.001) and an aggressive growth pattern (P = 0.03) by univariate analysis and age (P <0.001) and distant metastases (P <0.001) by multivariate analysis. Tumor size (P = 0.07) was included in the regression model. Total thyroidectomy appeared to provide a survival advantage for intermediate risk patients. High-risk patients treated by lobectomy had a poorer prognosis.

CONCLUSIONS

Total thyroidectomy may provide a survival advantage for intermediate-risk patients with DTC. A prospective randomized trial with 200 such patients is required to confirm this finding.

Thyroid carcinoma

The issue of appropriate management for thyroid neoplasms remains unsettled. Confusion concerning histology and classification, controversy as to appropriate therapy, the relative indolence of most differentiated thyroid tumors, and various levels of surgical skill have contributed to the prejudice of various approaches to the management of such neoplasms. It appears unlikely that the controversy will be resolved in the immediate future. If total thyroidectomy can be performed by a skilled surgeon with minimal complications, this approach seems theoretically justifiable for the management of most differentiated tumors, facilitating follow-up postoperatively. Conclusive evidence for improved survival with this rationale is insufficient.

Delayed aerodigestive tract complications following combined therapy for thyroid cancer

Radical surgery for papillary adenocarcinoma of the thyroid has been associated with a significant incidence of complications. In some instances, postoperative irradiation is given when there is some suspicion of persistent or occult disease, although thyroid suppression and ablative radioiodine therapy have proved to be very effective adjuvants to surgery. Three patients with papillary adenocarcinoma of the thyroid developed severe, delayed complications 25, 7, and 2 years, respectively, after treatment with primary radical surgery and postoperative irradiation. The degree of injury to the aerodigestive tract as a result of the surgery and irradiation therapy makes treatment difficult regardless of the modality. The possible mechanisms that cause these complications, along with proposed methods of treatment, are discussed.

Surgery for thyroid carcinoma

The cases of thyroid carcinoma treated at this hospital during the period 1948 to 1981 were reviewed retrospectively. Nine hundred eighty-six patients with thyroid nodules were operated on. One hundred fifty-two were thyroid carcinoma (59 papillary, 36 mixed papillary-follicular, 30 follicular, 20 anaplastic, 5 medullary, and 2 Hurthle cell tumors). There was a 92% follow-up for a mean of 10 years. In the last decade, patients presented at a younger age, the female predominance was diminished, and 15% had had previous neck irradiation. Surgery consisted of total (27) or subtotal thyroidectomy (89), lobectomy or nodulectomy (24), and biopsy (12). Total thyroidectomy had an incidence of postoperative complications that was 20 times higher than that with partial thyroidectomy (P less than 0.001). Disease-related death, recurrence, and survivor status were discussed. There was no significant difference between total versus subtotal thyroidectomy. This study reaffirms the usefulness of subtotal resection and the avoidance of morbidity of more radical total thyroidectomy surgery.

Total thyroidectomy. A review of 213 patients

During a 10.5-year period ending in June 1982, total thyroidectomy was performed on 213 patients at the Vanderbilt University Medical Center. A nonfunctioning nodule on technetium scan was the primary indication for operation. Twenty-one of 213 patients had undergone previous partial thyroidectomy. The pathologic changes in the excised thyroids were carcinoma (81 patients), thyroiditis (27 patients), multiple benign adenoma (16 patients), thyrotoxicosis (27 patients), multinodular goiter (56 patients), and C-cell hyperplasia (three patients). Three total thyroidectomies were performed in search of a parathyroid adenoma. Fourteen patients had coexistent primary hyperparathyroidism. Excluding 12 patients with medullary carcinoma, 25% of all other patients with carcinoma would have had unrecognized tumor left in the remaining lobe had a total thyroidectomy not been performed. Calcium supplements were required in 59 patients during hospitalization, but only 2.8% of the patients developed permanent hypoparathyroidism. Since the adoption of Thompson's technique of total thyroidectomy, only one of the 128 patients (0.8%) has sustained permanent hypoparathyroidism. Two patients exhibited transient recurrent laryngeal nerve palsies without permanent nerve damage. There were no operative deaths. The low morbidity of total thyroidectomy appears to justify its use in all patients with differentiated thyroid malignancy. With surgeons experienced in this technique, total thyroidectomy should also be considered as the primary treatment for many other patients requiring thyroidectomy.

Primary hyperparathyroidism and nonmedullary thyroid cancer

Of 2,058 patients who had surgically proven primary hyperparathyroidism at the Mayo Clinic from 1965 through 1979, 51 or 2.5 percent had associated nonmedullary thyroid carcinoma. A history of radiation exposure to the head and neck was obtained in 14 of 43 patients questioned. Thyroid disease consisted of grade 1 papillary adenocarcinoma in 48 cases and pure follicular adenocarcinoma in 3 cases. The parathyroid disease included 41 single adenomas and 5 cases of parathyroid hyperplasia; 5 patients had 2 adenomas. At follow-up, none of the patients had evidence of metastatic thyroid carcinoma. Ten patients were receiving calcium or vitamin D supplementation for protracted hypocalcemia presumably due to the increased insult to the parathyroids from combined bilateral thyroidectomy and parathyroidectomy. More consecutive thyroidectomy, along with parathyroid autotransplantation when indicated, will provide definitive treatment of the thyroid cancer and at the same time minimize the risk of postoperative hypoparathyroidism.