الفهرس | Only 14 pages are availabe for public view |
Abstract The incidence of thyroid carcinoma is reported to be 36 to 60 new cases per million populati.on per year. The incidence of thyroid carcinoma in clinically evident solitary thyroid nodules that are surgically resected varies from 10 to 30 percent. Thyroid carcinomas demonstrate a 3 : 1 female predomince. An increasing awareness of thyroid carcinoma and refinements in the histological diagnosis of carcinoma by pa’t.ohlogte’ts would partly responsible for the increasing i.nc’.dence of care inoma . Well differentiated carc;nomas derived from the thyroid follicular cell can be divided into two broad groups on the basis of their biological behaviour. These two types are termed ” papillary” and” follicular” carcinomas respectively, various subtypes of papillary and follicular carcinomas behaved as if they were consequetive stages of malignancy rather than as separate subtypes. The diagnosis of malignant tumor is usually obvious once there has been extra-thyroid spread, when there is ·no eV;dence of extrnthyroid spread, the erowth except for the very occasional carcinoma which develops in a multinodular goitre presents as a clinically solitary nodule. The factors in the history and physical examination that lead the physician to suspect cancer include a history of previous external radiation therapy; the relatively recent onset of 8 firm, hard, single nodule in the thyroid, and the obvious presence of cervical lymphadenopathy. Although, women are more commonly affected than men, nodules are uncommon in men and are more likely to be cancer. A family history of thyroid cancer should raise the susnicion of 8 multiple endocrine neoplasia syndrome. Except for the determination of thyrocalcitonin in medullary carcinoma of the thyroid, the only unequivocal diagnostic tool in thyroid cancer is biopsy. It should be emphasized that thyroid ultrasonography is a reliable examination for demonstration of multinodular disease, which can be valuable in the evaluation of a suspect thyroid lesion. The comb;nation of findings of a cold, solid thyroid nodule should stUI be regarded as a strong indication for obtaining a cellular diagnosis. The opposite finding of warm or cystic nodules, however, is not a valid indication of benignity. Fi.nally, it is concluded that both sot nttscann t ng and ultrasonography are not reliable discriminants’ in the diagnosis of thyroid cancer. Other diagnostic modalities such as thermography and lymphography have been employed but are much less specific. -114- The management of thyroid cancer continues to be controversial. The extent of primary treatment. whether conservative or total resection of the thyroid gland. the use of elective neck disection. the use of radionuclide for gland ablation and the postoperative use of thyroid suppression are questions which continues to face the managing physician and surgeon. ewing to the indolent nature of well-differentiated thyroid carcinoma. it is difficult to draw conclusions concerning the best method of management. The goals of sur-g icaI treatment for malignant thyroid lesions, are both clear-cut and concise viz. no hospital deaths, no postoperative morbidity and long-term tumor-free survival. The results of surgical treatment for most malignant thyroid lesions are today pleasing for both patients and surgeon. A meticulous surgical technique should maintain this level of satisfaction. There continues to be a lack of general agreement on the cause. pathology, treatment and prognosis of pat ierrt s wLth well differentiated thyroid carcinoma. The f’oH owtng factors have been shown to influence the prognosis of well differentiated thyroid carcinoma : age, sex, size and extent of primary tumor, histologic type, presence and extent of capsular invasion, stage. -ll5- extent of surgery and adjunctive postoperative therapy. Because ~\ well-differentiated thyroid carcinoma is uncommon, slow growing and generally indolent, long-term follow-up studies of large numbers of patients are necessary to evaluate differing modes of therapy and other factors that influence survival. If the routine diagnosti.c fine-needle aspiration biopsy of thyroid nodules is combined with cellular DNA analysis, it can be used both as a diagnostic and prognostic exam~nation. It is concluded that patients with aneuploid differentiated thyroid tumors have poorer prognosis than patients with diploid tumors. DNA aneuploidy is associated with the strongest prognostic factor found namely, age at diagnosis and also tumor size and grade of differentiation. Tncreased probability of DNA aneuploidy with advancing age explains at least partially why older pat;ents with d’fferentiated thyroid care lnoma have poor i prognosis. |