THYROID SURGERY IN AN AREA OF IODINE DEFICIENCY Anil K. Sarda, MS,1 Man M. Kapur, FRCS2 1 Department of Surgery, Maulana Azad Medical College & Lok Nayak Hospital, New Delhi, India. E-mail: [email protected] 2 All India Institute of Medical Sciences, 27 RPS, Triveni-1, New Delhi 110017, India

Accepted 11 October 2004 Published online 16 March 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/hed.20154

Abstract: Background. The catchment area of the patients under study was the sub-Himalayan plains, which are recognized as iodine-deficient areas. Methods. A retrospective analysis of 1576 surgically treated patients with thyroid disorders is presented. The indications for surgery were hyperthyroidism or cytologically diagnosed malignancy and large size, pressure symptoms, cosmesis, suspicious cytologic findings for malignancy, and clinical suspicion of malignancy in clinically benign euthyroid goiters. Results. Histologically, 83 of 703 solitary thyroid nodules, 36 of 329 clinically benign euthyroid multinodular goiters, and four of 181 Graves’ disease were cancers. Of all follicular cell cancers in this study, 132 were papillary, 83 were follicular, and 38 were anaplastic and squamous cell cancers. The different histologic types exhibited an aggressive clinical behavior, with advanced lesions with cervical lymph node involvement and distant metastases frequently seen at presentation. Locoregional recurrence occurred frequently even after radical surgical ablation, and overall mortality caused by the disease was high. Conclusions. Even well-differentiated cancers pursued a virulent clinical course with high mortality, despite routine radical surgical and radionuclide ablation. A 2005 Wiley Periodicals, Inc. Head Neck 27: 383 – 389, 2005 Keywords: thyroid; iodine deficiency; nodules; carcinoma; management

Correspondence to: A. K. Sarda B 2005 Wiley Periodicals, Inc.

Thyroid Surgery in an Endemic Area

In India, approximately 120 million people live in iodine-deficient areas, and of these areas, one third are recognized as goitrous.1,2 The difficulties faced by physicians in these areas are manifold. A large population of people in these socioeconomically backward areas is illiterate, living in remote areas sometimes far removed from a medical center. Because goiters are common, most neck swelling is disregarded by the patients until they grow to a large size or produce symptoms. A large number of such patients with thyroid swelling feel perfectly well and can perform hard work despite the goiter, which is prevalent in the family and among neighbors. At the same time, it is difficult to recognize which goiters harbor malignancy. Physicians cannot approach every thyroid swelling as a neoplastic disorder requiring intensive diagnosis and therapy, because benign goiters are definitely many times more frequent than malignant goiters. On the other hand, high circulating thyroid-stimulating hormone (TSH) levels are also reported to be responsible for the initiation and progression of thyroid cancer. There is evidence of the considerable variations in the incidence of thyroid cancers in different geographic regions.3

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Data on the incidence of thyroid cancer is meager in most areas of relative and absolute iodine deficiency. The effect of iodine deficiency on the natural history of thyroid cancer is suspected but ill defined. Reports suggest that thyroid cancer in endemic goitrous areas pursues an aggressive clinical course, with a preponderance of follicular and anaplastic tumors. Reports that even early stages of thyroid cancer in these areas pursue an unrelenting clinical course makes it mandatory that no cancer be missed among the thyroid disorders managed in the outpatient department. In this regard, it becomes important that an objective preoperative diagnosis be made to avoid excess operations for benign disorders. The purpose of this retrospective analysis is to define the clinical profile of thyroid disorders in northern India, which has large endemic goitrous areas. This, in turn, would render the therapeutic approach more rational. We believe the approach today is rendered more controversial because of limited experience with this disorder by clinicians, the varied natural history of thyroid cancer, and difficulties encountered in the diagnosis of thyroid cancer in areas of high goiter incidence.

MATERIALS AND METHODS

This study is a retrospective analysis of 1576 cases from a tertiary care center that caters to a population from the sub-Himalayan plains of northern India, which is officially recognized as an endemic goitrous area.4 All patients were managed by the same surgical team, and their case records were maintained on a predetermined ProForma, which included data on the patient’s clinical history and findings at the time of admission; the duration of the disease, which was recorded as coincidental with the patient first noticing the goiter; history of sudden growth of the goiter; pain; any change in the patient’s voice; the characteristics of the thyroid swelling; and any evidence of local and/or distant metastases. The goiters were classified as follows: (1) solitary thyroid nodule (STN), defined as a single nodule of either lobe or isthmus; (2) multinodular goiter (MNG), diagnosed when more than one nodule was felt in the thyroid; (3) hyperthyroidism, as recorded on the basis of clinical findings; and (4) thyroid carcinoma, recorded clinically as overt (ie, if there was history of rapid increase in size, if the patient’s voice changed, if the goiter was hard or fixed to the surrounding structure,

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if there was either local spread or metastasis to the regional lymph nodes or distant organs at first admission to the hospital). Disease in all cases was staged on the basis of the clinical findings (Union Internationale Contre le Cancer [UICC], 2002).5 Since 1983, hormonal status (serum triiodothyronine [T3], thyroxine [T4], and TSH) was measured using the commercially available radioimmune assay kits. Thyroid uptake of 131I determined 4 and 24 hours after administration of 15 ACi of the isotope using a rectilinear scanner was performed routinely until 1990. The nodule was designated as ‘‘cold,’’ ‘‘uniform,’’ or ‘‘hot’’ if it was hypo-, iso-, or hyperfunctioning. Fine-needle aspiration cytology (FNAC) has been performed routinely since 1983 for all thyroid swellings and neck masses, according to the technique described earlier.1 Histopathologic findings of thyroid cancers were reported according to the World Health Organization classification1; all histopathologic slides were reviewed by the same pathologists for the purpose of this study. Operative procedures were classified as neartotal thyroidectomy when both thyroid lobes and isthmus were excised, but a rim of the posterior capsule was spared to protect the parathyroid glands and the recurrent laryngeal nerve on at least the side that was free of the disease clinically. The operation was performed as a onestage procedure in cases in which thyroid cancer was documented preoperatively by histologic or cytologic analysis. In STNs, the affected lobe plus the isthmus (hemithyroidectomy) was removed. In cases in which the histologic findings of the excised tissue revealed a malignancy and the patient agreed to a second operation, a completion thyroidectomy was performed, usually within 7 to 10 days of the initial operation. Subtotal thyroidectomy was performed for the clinically benign euthyroid and hyperthyroid glands, and a biopsy was reserved only for the locally advanced cancers. Postoperative complications were documented, including the findings of laryngoscopic examination. After a near-total thyroidectomy, no substitution T4 therapy was administered for 4 to 6 weeks after surgery to enhance endogenous TSH secretion. Subsequently, a totalbody scan with 131I was performed to detect the amount of thyroid remnant and/or metastatic foci of the cancer for which an ablative dose of 131 I was administered. Further follow-up was done in conjunction with the Department of Nuclear Medicine.

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FIGURE 1. Surgically treated thyroid disorders (MNG, multinodular goiter; Ca, carcinoma; STN, solitary thyroid nodule; figures in parentheses denote number of cancers in that particular group). [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Significance of the various parameters was calculated by the chi-square test.

RESULTS

A total of 1576 patients with thyroid disorders underwent surgery. The distribution of various clinical presentations of thyroid disease is shown in Figure 1. The age and sex distribution of the patients by the various surgically treated thyroid disorders is shown in Table 1. The largest single indication for surgery was the presence of an STN in 703 cases; 83 of these (11.8 %) were cancers (Table 2). The male/female ratio among the patients with STN cancers was 1.0.9 compared with a male/female ratio of 1.0:2.5 among the patients with benign STN. The incidence of malignancy did not differ significantly between patients