This updated second edition describes all current diagnostic techniques for thyroid cancer, including FDG-PET and MRI. In recent years these modalities have documented hitherto hidden radioiodine-negative metastases, thus improving surgical therapy. In some 10% of differentiated thyroid cancers, the well-known treatment tools of surgery and radioiodine therapy are not sufficient. New treatment modalities such as high-dose radioiodine therapy, redifferentiation therapy with retinoic acid and recombinant TSH are therefore highlighted.
The use of imaging technology in the investigation of disorders of the head and neck has increased awareness of nodular thyroid disease in all areas of medicine. But are there enough important unanswered questions about thyroid cancer and has there been enough progress in the past decade to justify yet another textbook on the subject? The editors of Thyroid Cancer obviously believe so, and they have generally done an excellent job of putting together a concise book that highlights the advances and the controversies that surround them.
Tumors derived from thyroid epithelial cells are among the most common clinically recognized neoplasms. They include benign follicular adenomas, well-differentiated papillary or follicular carcinomas, poorly differentiated ``insular'' carcinomas, and dedifferentiated, or anaplastic, carcinomas. The spectrum ranges from benign occult papillary microcarcinomas to rapidly progressive anaplastic cancers. The changes in the epidemiology, classification, and worldwide pattern of detection of these thyroid neoplasms are sufficient to make this book a useful reference.
Unfortunately, the histology and molecular pathogenesis of nodular thyroid disease have been incorporated into one chapter, which does not provide enough detailed coverage of each subject. Our knowledge of the cause of thyroid cancer is just emerging, and there is increasing evidence that exposure to external radiation has a causative role; such exposure includes radiotherapy for cancers of the head and neck and treatment for acne and tonsillar disease. This is also observed in populations exposed to radioactive iodine fallout from nuclear disasters, most recently exemplified by the Chernobyl accident. Exposure to radioactivity there has had its highest impact in the young, and this is the subject of a separate chapter. Radiation has also been implicated in the RET-PTC gene rearrangement that is now considered to play a key part in the transformation of thyroid cells. The book also discusses the important role of dietary intake of iodine in the development of goiter and how iodine sufficiency may have contributed to the reduced incidence of follicular carcinomas.
When a thyroid nodule is detected, the most valuable diagnostic technique is fine-needle aspiration. Unfortunately, nearly half of aspirates are insufficient or inconclusive for diagnosis; molecular tools may circumvent this problem. A more detailed discussion of fine-needle aspiration and clinical management would have been welcome.
The identification of activating germ-line RET mutations is now accepted as an indication for prophylactic thyroidectomy in childhood, underscoring the rapidly growing importance of molecular tools in the diagnosis of medullary thyroid carcinomas. Moreover, distinct RET mutations are associated with unique clinical phenotypes. This subject is well covered, and treatment guidelines are seamlessly integrated with discussions of disease pathobiology.
The discussions of head and neck imaging are the major strength of the book. Indeed, all current methods are not only covered in great detail but are also the subject of the best-illustrated part of the book. The use of recombinant thyrotropin in functional imaging of patients receiving thyroid hormone is generously covered. Moreover, the expanding role of imaging in staging of thyroid cancer with somatostatin-receptor scintigraphy and other novel radioisotopes is reviewed.
The most useful prognostic markers in well-differentiated carcinoma of thyroid follicular epithelium are the characteristics of the patient, the size of the tumor, and the extent of disease. In addition to the size of the tumor and the age and sex of the patient, the controversial influences of lymph nodes and occult solitary and multiple microcarcinomas are reviewed. The presence of cervical lymph-node metastases, whether microscopic or clinically evident, may increase the risk of recurrence but not affect mortality. In contrast, extrathyroidal extension predicts a worse prognosis, and the presence of distant metastases is the hallmark of an aggressive tumor. In patients with metastatic disease, the site of metastases and their ability to take up radioiodine are important factors. Thus, knowledge of the role of the sodium iodide symporter and its regulation by differentiating factors holds promise for the identification and treatment of patients with metastatic thyroid cancer.
The care of patients with tumors of thyroid follicular epithelium is well discussed. These tumors are generally amenable to surgical resection, but aggressive surgery is not usually indicated. The difficulty often lies in determining which patients should undergo surgery, when surgery should be performed in patients with uncertain diagnoses, and whether a complete thyroidectomy is needed, and the indications for prophylactic thyroidectomy in heritable diseases are detailed.
I highly recommend this book for trainees and practitioners in the fields of general medicine and surgery as well as specialists in endocrinology, oncology, and otolaryngology. Despite its compact size and relatively low price, it provides overviews of many highly relevant and common problems in the identification and care of patients with thyroid nodular disease.
Shereen Ezzat, M.D.
Copyright © 2001 Massachusetts Medical Society. All rights reserved. The New England Journal of Medicine is a registered trademark of the MMS.
