Hiroo Masuoka

Prognostic Impact of Serum Thyroglobulin Doubling-Time Under Thyrotropin Suppression in Patients with Papillary Thyroid Carcinoma Who Underwent Total Thyroidectomy

BACKGROUND Detectable serum thyroglobulin (Tg) in patients with papillary thyroid carcinoma (PTC) after total thyroidectomy implies unsuccessful surgery, indicating a high risk of recurrence. Serum Tg kinetics in such patients have not been extensively studied. We studied serum Tg kinetics in patients with suppressed serum thyrotropin levels and undetectable anti-Tg antibody to minimize the effects of these factors on Tg values, and evaluated the relationship of prognosis to the serum Tg doubling-time. METHODS Between January 1998 and December 2004, 1515 patients with PTC underwent total thyroidectomy in Kuma Hospital. After excluding patients with other thyroid cancers and those positive tests for anti-Tg antibody, there were 426 patients with 4 or more serum Tg measurements at a time that serum thyrotropin concentrations were <0.1 mIU/L. These patients were selected for the present retrospective study. Tg doubling-time was computed using Tg values measured during routine follow-up. Patients were followed for a mean of 88.1 months and a median of 86.7 months. RESULTS Of the 426 patients, 137 patients had 4 or more measurements that revealed detectable Tg in serum Tg. The Tg doubling-time (DT), calculated using all available data, varied widely, and were grouped into those that were <1 year (17 patients), those that were 1-3 years (21 patients), and those that were ≥ 3 years (30 patients), as well as those with a negative value due to decrease in serum Tg (69 patients). There were also 88 patients who had three or fewer serum Tg measurements that showed detectable Tg levels, as well as 201 patients in whom serum Tg measurements were below the lower limit of detection. In the group of patients with a Tg-DT of <1 year the cause specific survival at 10 years was 50%, and in the group with a Tg-DT of 1-3 years it was 95%. In all other groups it was 100%. Many classical prognostic factors (TNM stage, age, and gender) as well as the Tg-DT were significant indicators of survival by univariate analysis, but Tg-DT remained the only independent predictor by multivariate analysis. Tg-DT was also the only independent predictor of distant metastases and loco-regional recurrence on multivariate analysis. Tg-DT calculated using only the first four data [Tg-DT (first four data)] was also the only independent predictor of survival, distant metastases, and loco-regional recurrence on multivariate analysis. CONCLUSIONS Tg-DT (all data or first four data) is a very strong prognostic predictor superior to the classical prognostic factors in patients with PTC.

Incidences of Unfavorable Events in the Management of Low-Risk Papillary Microcarcinoma of the Thyroid by Active Surveillance Versus Immediate Surgery

Background: The incidence of papillary microcarcinoma (PMC) of the thyroid is rapidly increasing globally, making the management of PMC an important clinical issue. Excellent oncological outcomes of active surveillance for low-risk PMC have been reported previously. Here, unfavorable events following active surveillance and surgical treatment for PMC were studied. Methods: From February 2005 to August 2013, 2153 patients were diagnosed with low-risk PMC. Of these, 1179 patients chose active surveillance and 974 patients chose immediate surgery. The oncological outcomes and the incidences of unfavorable events of these groups were analyzed. Results: In the active surveillance group, 94 patients underwent surgery for various reasons; tumor enlargement and the appearance of novel lymph node metastases were the reasons in 27 (2.3%) and six patients (0.5%), respectively. One of the patients with conversion to surgery had nodal recurrence, and five patients in the immediate surgery group had a recurrence in a cervical node or unresected thyroid lobe. All of these recurrences were successfully treated. None of the patients had distant metastases, and none died of the disease. The immediate surgery group had significantly higher incidences of transient vocal cord paralysis (VCP), transient hypoparathyroidism, and permanent hypoparathyroidism than the active-surveillance group did (4.1% vs. 0.6%, p < 0.0001; 16.7% vs. 2.8%, p < 0.0001; and 1.6% vs. 0.08%, p < 0.0001, respectively). Permanent VCP occurred only in two patients (0.2%) in the immediate surgery group. The proportion of patients on L-thyroxine for supplemental or thyrotropin (TSH)-suppressive purposes was significantly larger in the immediate surgery group than in the active surveillance group (66.1% vs. 20.7%, p < 0.0001). The immediate surgery group had significantly higher incidences of postsurgical hematoma and surgical scar in the neck compared with the active surveillance group (0.5% vs. 0%, p < 0.05; and 8.0% vs. 100%, p < 0.0001, respectively). Conclusions: The oncological outcomes of the immediate surgery and active surveillance groups were similarly excellent, but the incidences of unfavorable events were definitely higher in the immediate surgery group. Thus, active surveillance is now recommended as the best choice for patients with low-risk PMC.

Effect of portocaval shunt on residual extreme small liver after extended hepatectomy in porcine.

BackgroundWhen residual liver volume is extremely small after extended hepatectomy, postoperative hepatic failure may ensue. The cause of the hepatic failure is likely associated with the portal hypertension after hepatectomy. We investigated the effects of portocaval shunt on portal hypertension in producing sinusoidal microcirculatory injury after extended hepatectomy in pigs.MethodsFourteen pigs were divided into two groups: a group without a shunt, in which extended hepatectomy was carried out (i.e., residual volume was 17% of the whole liver), and a group with a shunt, in which extended hepatectomy was carried out and a portocaval shunt was inserted. The portocaval shunt was placed by side-to-side anastomosis between the portal vein and the inferior vena cava.ResultsIn the group without a shunt, all pigs died of hepatic failure within postoperative day 3. In the group with a shunt, all pigs were alive for more than 4 days, and 4 pigs survived longer than 7 days. Portal vein pressure after hepatectomy was 15.9 ± 3.8 mmHg in the group without a shunt and 10.5 ± 0.6 mmHg in the group with a shunt (P < 0.01). The portal vein flow after 83% hepatectomy in the group without a shunt increased significantly more than at laparotomy and in the group with a shunt (P < 0.01). In the group without a shunt, remarkable destruction of the sinusoidal lining and edema of the portal triad and hydropic change of hepatocytes were observed 1 hour after hepatectomy, but these findings were not observed in the group with a shunt.ConclusionsThese results indicate that, after extended hepatectomy, overload of portal flow is one of the most significant risk factors of hepatic failure by sinusoidal microcirculatory injury.

Imaging Studies in Sixty Patients with Acute Suppurative Thyroiditis

BACKGROUND Pyriform sinus fistulae are the major routes of infection in acute suppurative thyroiditis (AST). There have been only a few reports describing imaging studies in AST. We reviewed our imaging studies in patients with AST to elucidate its features so as to facilitate its diagnosis and treatment. METHODS We reviewed ultrasonography (US) examinations, computed tomography (CT) scans, and barium swallow studies performed on 60 patients with the AST who were seen for medical care between 1998 and 2008 and were retrospectively reviewed. All of these patients had pyriform sinus fistulae. RESULTS In the acute inflammatory stage, US showed a hypoechoic lesion spreading in and around the affected thyroid lobe, destruction of the lobe, and abscess formation in the neck. CT scans demonstrated similar features with clearer anatomical involvement and edema in the ipsilateral hypopharynx. These findings allowed easy diagnosis of AST. However, in the early inflammatory stage US showed an unclear hypoechoic area in the affected lobe and CT scans showed a nonspecific low-density area. These findings often led to erroneous diagnoses of subacute thyroiditis. A careful review of the US studies demonstrated that the following findings are characteristic of acute suppurative thyroidits: a perithyroidal hypoechoic space, effacement of the plane between the thyroid and perithyroid tissues, and the hypoechoic lesions being unifocal. The former two are not seen in subacute thyroiditis, and hypoechoic lesions in subacute thyroiditis are usually multiple and often bilateral. In the late inflammatory stage, US and CT scans often showed atrophy and an unclear hypoechoic or low-density area in and around the affected lobe. To detect pyriform sinus fistulae, barium swallow studies are more sensitive than US or CT scans. CONCLUSION During the acute inflammatory stage of AST, both US and CT scans showed inflammatory processes in and around the affected thyroid lobe, although the CT scans more clearly demonstrate the anatomical locations involved. In the early inflammatory stage, these features may lead to an erroneous diagnosis of subacute thyroiditis. Careful US studies should indicate the correct diagnosis, which can then be proven by a barium swallow study or fine-needle aspiration followed by cytological examination and bacterial culturing.

Significance of prophylactic modified radical neck dissection for patients with low-risk papillary thyroid carcinoma measuring 1.1–3.0 cm: First report of a trial at Kuma Hospital

PurposePapillary thyroid carcinoma (PTC) frequently metastasizes to and recurs in regional lymph nodes. Of the two compartments, the central compartment can be dissected through the same wound as the thyroidectomy, and the central node dissection (CND) is routinely performed in most Japanese surgical departments. However, the indications for prophylactic lateral compartment dissection (modified radical neck dissection [MND]) for low-risk PTC remain unclear. In this study, we investigated the indications for prophylactic MND for PTC patients with tumor measuring 1.1–3.0 cm without significant extrathyroid extension or distant metastasis.MethodsWe investigated the lymph node disease-free survival (LN-DFS) rates of 829 patients who underwent CND and of 414 patients who underwent MND and CND between 2005 and 2007 at Kuma Hospital.ResultsThe LN-DFS of these two groups was not significantly different. In the subset of patients with CND only, clinical central node metastasis (N1a) significantly predicted a worse LN-DFS. All N1a patients recognized as showing recurrence developed such recurrence in the lateral compartment. Other conventional prognostic factors, such as sex and age, were not related to LN-DFS.ConclusionTaken together, N1a patients with low-risk PTC measuring 1.1–3.0 cm can be considered as candidates for prophylactic MND.

Prospective randomized study on injury of the external branch of the superior laryngeal nerve during thyroidectomy comparing intraoperative nerve monitoring and a conventional technique.

The external branch of the superior laryngeal nerve (SLN) is susceptible to injuries during thyroidectomy, causing voice impairment. Intraoperative nerve monitoring may facilitate identification of the nerve, reducing voice impairment.

Metastatic carcinoma to the thyroid gland from renal cell carcinoma: role of ultrasonography in preoperative diagnosis

BackgroundPatients with metastases to the thyroid from renal cell carcinoma (RCC) that need surgical management are not many and unfamiliar to clinicians and thyroid endocrinologists. Therefore, little information is available on ultrasonographic features of metastatic carcinoma in the thyroid. The strategic value of ultrasound in preoperative surgical planning for patients with thyroid nodules has become increasingly appreciated. The purposes of this article are to clarify the ultrasound characteristics of metastatic carcinoma to the thyroid from RCC by evaluating many patients in one institute, and to investigate the role of ultrasonography in preoperative diagnosis.MethodsTen patients with these carcinomas who had undergone surgical management were investigated clinically and ultrasonographically. Ultrasonographic features to be evaluated were the form of involvement in the thyroid, size, shape, pattern, calcifications, vascularity, and tumor thrombus. Clinical features were previous history of RCC, serum thyroglobulin levels, cytology, preoperative diagnosis, and surgery.ResultsUltrasonographic features of these carcinomas were more likely to involve a solitary, irregular, and solid without calcifications, and prominent intra-tumoral vascularity and tumor thrombus in the vein. These patients tended to be older, and to have relatively late recurrence in the thyroid, RCC in the right kidney as the primary site, and relatively low serum thyroglobulin levels.ConclusionsMetastatic carcinomas to the thyroid from RCC presented highly characteristic features on ultrasonography. These ultrasonographic features combined with cytological findings and previous medical history of RCC can provide the optimal process for the preoperative diagnosis of such patients.

Innervation of the cricothyroid muscle by the recurrent laryngeal nerve

The recurrent laryngeal nerve (RLN) and the external branch of the superior laryngeal nerve (SLN) are generally thought to innervate the endolaryngeal muscles and the cricothyroid muscle (CTM), respectively. Meticulous anatomic studies found communication between these nerves (ie, the human communicating nerve). In this study, we report the innervation of the CTM by the RLN.

Estimation of the lifetime probability of disease progression of papillary microcarcinoma of the thyroid during active surveillance

Background. We reported that a minority of patients with low‐risk papillary microcarcinoma of the thyroid showed disease progression during active surveillance and that older patients had significantly lower disease progression rates than younger patients. Here, we estimated lifetime (≤85 years old) probabilities of disease progression during active surveillance according to the age at presentation based on age decade‐specific disease progression rates. Methods. From 1993–2013, 1,211 low‐risk papillary microcarcinoma patients aged 20–79 years underwent active surveillance at Kuma Hospital. We calculated the disease progression rate at the 10‐year point of active surveillance for each age‐decade group (20s to 70s) with the Kaplan‐Meier method. The lifetime disease progression probability for each age group was calculated as (1 − cumulative probability of progression‐free survival calculated with age decade‐specific disease progression rates) until the patients reached their 80s (i.e., 85 years on average). Results. The age decade‐specific disease progression rates at 10 years of active surveillance were 36.9% (20s), 13.5% (30s), 14.5% (40s), 5.6% (50s), 6.6% (60s), and 3.5% (70s); the respective lifetime disease progression probabilities were 60.3%, 37.1%, 27.3%, 14.9%, 9.9% and 3.5% according to the age at presentation. Conclusion. The estimated lifetime disease progression probabilities of papillary microcarcinoma during active surveillance vary greatly according to the age at presentation.

Laryngeal approach to the recurrent laryngeal nerve involved by thyroid cancer at the ligament of Berry

BACKGROUND Thyroid cancer often involves the RLN at the ligament of Berry, which makes preservation of the nerve difficult. If the portion of RLN is resected, finding the peripheral RLN for reconstruction is difficult. Here we describe a laryngeal approach performed before dissecting the RLN to overcome these problems. METHODS Between January 2007 and April 2011, 13 patients with papillary thyroid carcinoma had unilateral RLN involvement by the cancer at the ligament of Berry. Preoperatively, 8 had functioning vocal cords and 5 had unilateral paralysis. The laryngeal approach involves dividing the inferior pharyngeal constrictor muscle along the lateral edge of the thyroid cartilage and identifying the nerve under the muscle or behind the thyroid cartilage. This procedure was performed before resecting the tumor in 10 patients (Group 1) and after resection in the remaining 3 (Group 2). RESULTS In Group 1, the RLN could be preserved with sharp dissection in 3 with functioning vocal cords preoperatively. Postoperatively they restored vocal cord function. The remaining 7 needed resection of the portion of RLN. RLN reconstruction was easily, since the peripheral RLN had already been identified. All patients in Group 2 needed resection of the portion of RLN. The peripheral RLN was identified in 2, and ansa-RLN anastomosis was performed. However, this was not possible in 1 patient. CONCLUSION In patients with thyroid cancer involving the RLN at the ligament of Berry, performing the laryngeal approach before dissecting the nerve facilitates preservation or reconstruction of the nerve.