Surgery News - June 2008 - (Page 11)

JUNE 2008 • SURGERY NEWS ENDOCRINE SYSTEM 4-D CT Pinpoints Parathyroid Gland Preoperatively B Y J E F F E VA N S Else vier Global Medical Ne ws H O T S P R I N G S , VA . — Four-dimensional computed tomography scanning prior to reoperative parathyroid surgery may help endocrine surgeons localize the parathyroid gland amid scar tissue and distorted anatomy better than sestamibi or ultrasound imaging, according to the results of a retrospective study. A review of 45 patients who had previous neck surgery showed that 4-D CT correctly localized hyperfunctioning parathyroid glands in 80% of the patients before their reoperation, compared with 50% for sestamibi and 21% for ultrasound, Dr. Kelly K. Hunt reported at the annual meeting of the Southern Surgical Association. Reoperative parathyroid surgery can be more difficult than the first operation because scar tissue that forms from the previous surgery can distort the anatomy in the neck, said Dr. Hunt, an ACS Fellow who is professor of surgical oncology and experimental radiation oncology at the University of Texas M.D. Anderson Cancer Center, Houston. Reoperation also carries the risk of failing to cure the patient of hyperparathyroidism and causing morbidity from recurrent laryngeal nerve injury or hypoparathyroidism. Four-dimensional CT scanning has the potential to improve the localization of hyperfunctioning parathyroid glands by combining 3-D CT with the fourth “dimension” of perfusion, which provides information similar to what is obtained with CT angiography. The addition of perfu- This image was derived from fusion of sestamibi SPECT with conventional CT. sion shows a rapid uptake and washout that are “suggestive of hyperfunctioning glands, allowing for improved localization,” said Dr. Hunt, who presented the study for the endocrine surgery group at M.D. Anderson. The same group previously reported a sensitivity of 70% for 4-D CT in localizing the gland in the correct quadrant of the neck in a series of 75 patients with primary hyperparathyroidism. However, only 16% of the patients had undergone a reoperation (Surgery 2006;140:932-40). To determine the ability of 4-D CT to localize hyperfunctioning parathyroid glands in patients who had previous neck surgery, Dr. Hunt and her colleagues reviewed the cases of 45 patients with a biochemical diagnosis of sporadic primary hyperparathyroidism who underwent 4-D CT before reoperative neck surgery during 2004-2007. The study included three groups: patients with prior neck surgery for reasons other than hyperparathyroidism (group 1), prior unsuccessful ex- 4-D CT imaging identified a left inferior adenoma (left image) and a right superior adenoma (right image) in this patient. ploration of the neck for hyperparathyroidism without any removal of hyperfunctioning tissue (group 2), and prior exploration of the neck for hyperparathyroidism with resection of hyperfunctioning tissue (group 3). The review showed that 4-D CT correctly localized hyperfunctioning glands more often than did sestamibi or ultrasound imaging. The investigators defined localization not only as the lateralization of the gland but also as the specific neck quadrant in which it was located. Four-dimensional CT correctly localized hyperfunctioning glands in 36 of 45 patients (80%), compared with 22 of 44 patients (50%) for sestamibi and 9 of 42 (21%) for ultrasound. Four-dimensional CT proved to have significantly better overall sensitivity (88%) than did sestamibi (54%) or ultrasound (21%). It also had the greatest sensitivity in each of the three groups. In 42 patients with at least 6 months of follow-up data available, 39 were surgically cured of their hyperparathyroidism (21 patients in group 1, 8 in group 2, and 10 in group 3). Hypercalcemia remained in one patient in group 2 and in two patients in group 3. Three cases of permanent hypoparathyroidism occurred in group 2, but recurrent laryngeal nerve injury was not seen in any patients. Dr. Hunt said that patients in group 1 appear to have the best outcomes, whereas the glands in the group 3 patients were the most difficult to localize and cure. Patients in group 2 should be “approached with caution” because they appear to have a significant risk for permanent hypoparathyroidism,” she said. Thyroid Uptake Helped Limit Biopsies in Multinodular Disease B Y J E F F E VA N S Else vier Global Medical Ne ws C I N C I N N A T I — A thyroid uptake scan might be useful for limiting the number of biopsies that need to be taken from patients who have multinodular thyroid disease on ultrasound without any dominant pathological features, according to a small retrospective study. The results point out a beneficial use for thyroid uptake scanning (TUS), which has had a very limited role in the diagnosis of thyroid disease because of its inferiority to fine-needle aspiration biopsy (FNAB) in predicting the malignancy of thyroid nodules. TUS limited the number of FNABs that were necessary in 71% of patients, Dr. Scott M. Wilhelm reported at the annual meeting of the Central Surgical Association. Incidental thyroid nodules are generally nonpalpable and are typically discovered on diagnostic radiologic procedures performed for other reasons. Many patients with incidentally discovered disease have a single nodule. “Most of these patients really do not have previously known thyroid disease, but there is a caveat that sometimes, once a study has been done, if you palpate the neck you may actually be able to feel the nodule,” said Dr. Wilhelm, an endocrinologic surgeon in the division of surgical oncology at Case Western Reserve University, Cleveland. These nodules are commonly evaluated by testing thyroid-stimulating hormone levels and by ultrasound imaging of the thyroid. An FNAB can then confirm if they are benign or malignant. Some clinicians advocate doing FNAB on both “warm” and “cold” nodules, recommending against TUS, especially for a solitary nodule. “This leaves the role of thyroid uptake scanning for hyperthyroidism and occasionally in patients with follicu- Sagittal ultrasound of a right thyroid lobe shows two nodules, each 3.5 cm, without any worrisome features. lar neoplasms or nondiagnostic biopsies to try to avoid a surgical procedure,” noted Dr. Wilhelm, an ACS Fellow. But a rising number of patients who presented to Dr. Wilhelm’s clinic with incidentally discovered thyroid disease led him to try to determine whether TUS could be used to decide which nodules should be biopsied. Ultrasound detected multinodular thyroid glands without any dominant nodule to biopsy in 14 (20%) of 71 patients who had been referred to Dr. Wilhelm’s clinic during 2005-2007 with an incidentally discovered thyroid nodule. These 14 patients had similar-size nodules without features of malignancy on ultrasound. They had an average of about five nodules; most nodules 1 cm or greater in size varied by an average of only 4 mm. The 14 patients had 123I TUS, followed by FNAB of cold nodules. Patients with “hot” nodules, which are typically hyperfunctioning and “not overly worrisome for cancer,” were initially excluded from biopsy. If the nodules showed normal 123I uptake, Dr. Wilhelm used his discretion to decide which ones to biopsy. Nonbiopsied nodules were monitored for growth that might indicate malignancy with serial ultrasounds. All surgery was based on biopsy results. Overall, 9 patients had a cold nodule and 1 patient had a hot nodule, thereby reducing the number of biopsies performed on 10 (71%) of the patients. Of the nine cold nodules, three (33%) were malignant. Biopsies of the four patients with normal, uniform 123I uptake were benign. There was about 85% correlation between the nodules biopsied on ultrasound with those seen on TUS, he said. The three patients with malignant biopsies underwent thyroidectomy. Three of the remaining 11 patients were lost to follow-up. Another seven patients had one or two follow-up ultrasound tests (spaced about 6 months apart) without growth in any nodule. A growing nodule in the one remaining patient that had not been previously biopsied turned out to be benign. Cold nodules detected thyroid cancer with 100% sensitivity and 45% specificity. A cold nodule gave a positive likelihood ratio of 1.83, which reflects a slight increase in the chance of a cold nodule representing cancer. A cold nodule also gave a negative likelihood ratio of zero; a negative likelihood ratio of less than 0.1 represents a large and often conclusive decrease in the likelihood of papillary thyroid carcinoma occurring, Dr. Wilhelm said. The 33% rate of malignancy in cold nodules was higher than the traditionally expected rate of 5% seen in palpable nodules, but this might be explained by the fact that published studies have reported finding cancer in 7%-29% of incidentally discovered nodules, he said. COURTESY DR. SCOTT M. WILHELM IMAGES COURTESY DR. MELINDA M. MORTENSON

Table of Contents Feed for the Digital Edition of Surgery News - June 2008

Surgery News - June 2008 Contents Work Hours New Digs Banking Blood Improved Imaging

Surgery News - June 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.