Therapeutic Strategies and Clinical Outcome in Papillary Thyroid Microcarcinoma: A Multicenter Observational Study

PURPOSE

Papillary thyroid microcarcinoma (MPTC) has an excellent prognosis. We aimed to evaluate the evolution of therapeutic strategies over time and the clinical outcome of MPTC.

METHODS

In this retrospective multicenter observational study in a northwest Italian region, patients with intrathyroidal, unifocal tumor ≤1 cm in size, incidentally found at histology or preoperative cytology diagnosis, were included. Exclusion criteria were a previous head-and-neck irradiation and/or node metastases.

RESULTS

From 1985 to 2012, 437 patients had an MPTC diagnosis, which was incidental in 85% and preoperative in 15%. Patients with a preoperative diagnosis were younger at the time of diagnosis (47.6 ± 12.7 years, p < 0.01) and had a larger tumor (7.0 ± 2.5 mm, p < 0.0001) than patients with an incidental diagnosis (age 52 ± 13.5 years, size 4.4 ± 2.8 mm), but there were no differences in clinical outcome between both groups. We observed a significant (p < 0.001) reduction in radioiodine remnant ablation during the years. TSH levels were: <0.1 mIU/l in 27.5%, 0.1-0.5 mlU/l in 33.7%, 0.5-2.5 mlU/l in 32.6%, 2.5-4.2 mlU/l in 3.9%, and >4.2 mlU/l in 2.3% of patients. Six patients (1.37%) had nodal recurrence; 5 of them were cured after therapy. MPTC-linked mortality was null.

CONCLUSIONS

We confirmed the favorable clinical outcome of MPTC. Despite the reduction in radioiodine ablation, overtreatment of MPTC is still observed.

Differences between 99mTc-sestamibi and 99mTc-tetrofosmin uptake in thyroid and salivary glands: comparison with 99mTc-pertechnetate in 86 subjects

Tc-tetrofosmin seems to show a prolonged thyroid retention when compared with Tc-sestamibi; this may explain its poorer performance in the dual-phase parathyroid scintigraphy. In order to verify objectively whether and to what extent Tc-sestamibi and Tc-tetrofosmin uptake and retention differ in the thyroid gland, we performed a head-to-head comparison between the tracers in 86 euthyroid subjects enrolled in five centres. Data were compared with those of Tc-pertechnetate obtained from the same subjects. For comparison purposes, quantitative data from the salivary glands were also obtained. Tc-sestamibi showed a higher early thyroid uptake (2.26+/-0.52 vs. 2.01+/-0.49, respectively; P<0.002) and a lower retention (1.4+/-0.37 vs. 1.65+/-0.58, respectively; P<0.002) when compared with Tc-tetrofosmin. This finding provides an objective basis for the poorer results of Tc-tetrofosmin in dual-phase parathyroid scintigraphy. Delayed Tc-tetrofosmin salivary gland uptake was unexpectedly high and approached the Tc-pertechnetate value (2.29+/-0.56 vs. 2.46+/-0.75, respectively; P =not significant). This finding should be kept in mind in order to avoid interpretation pitfalls in thyroid and parathyroid imaging with Tc-tetrofosmin, as well as in other oncological imaging of the neck region. This study definitely establishes that Tc-tetrofosmin and Tc-sestamibi are not twin but rather sibling tracers.

Cerebral effects of hyperbaric oxygen breathing: a CBF SPECT study on professional divers

We investigated the effects on cerebral blood flow (CBF) of pure oxygen breathing exposure during dives in a group of professional divers, in both the normobaric (NBO) and the hyperbaric oxygen (HBO) breathing conditions. Using single photon emission computerized tomography (SPECT) and Tc-99m hexamethylpropylenamine oxime (HM-PAO), we studied 10 young divers and six normal volunteers. Divers were studied by SPECT in the NBO and HBO conditions, in two different sessions. The HBO state was obtained in a hyperbaric chamber at 2.8 ATA for 15 min. By ANOVA, we did not observe any significant difference in CBF distribution between controls and divers in both NBO and HBO conditions. By individual analysis, divers showed a decreased CBF in a total of 33 regions of interest (ROIs) during NBO and 46 ROIs during HBO with respect to control values. In particular, two divers showed a remarkable increase in the number of hypoperfused ROIs during HBO (+7 and +5 ROIs, respectively). Pure oxygen breathing exposure in young divers is associated with a patchy distribution of brain areas of hypoperfusion. This phenomenon is more pronounced in the HBO state than in the NBO state. Further studies on CBF are needed to help identify divers potentially prone to harmful oxygen effects.

Assessment of myocardial viability after thallium-201 reinjection or rest-redistribution imaging: a multicenter study. The Italian Group of Nuclear Cardiology

To establish the real nature of 201Tl defects in the assessment of myocardial viability (e.g., fixed versus reversible), 201Tl reinjection was evaluated in a multicenter trial involving 402 consecutive patients with ischemic heart disease and exercise 201Tl defects.

METHODS

Twelve hospitals, using the same type of gamma camera and computer software, adopted one of the two most widely used reinjection protocols. In 230 patients (Group A), reinjection was performed immediately after stress-redistribution planar imaging; in 172 patients (Group B), reinjection was performed on a separate day and followed by rest-redistribution imaging. The images were interpreted by three blinded observers in a core laboratory on a five-point qualitative scale; the reproducibility in visual scoring was excellent.

RESULTS

Groups A and B had a similar prevalence of myocardial segments with abnormal uptake at stress (39%, 40%), as well as with reversible (16%, 17%), partially reversible (21%, 19%) and irreversible (63%, 64%) defects at redistribution. After reinjection, 201Tl uptake improved in 27% and 36% of both partially reversible and irreversible defects in Groups A and B. No differences were found when comparing early and delayed reinjection imaging in Group B.

CONCLUSION

This study confirms the validity of 201Tl reinjection in a large, unselected population, but the discordance with stress/redistribution is less than has been previously reported for both 201Tl reinjection protocols, the prevalence of improved segments after reinjection was higher with the separate day approach.

[Stress myocardial scintigraphy in the pre- and postoperative diagnosis of ischemic cardiopathy. The correlations between the clinical aspects and the coronary angiographic picture]

With radioisotopes it is possible to study the heart obtaining complementary or substitutive informations to those provided by the most common noninvasive methods of myocardial assessment and by coronarography. This paper aim is to report experience with thallium 201 and 99mTc isonitrile in the diagnosis and followup of ischemic heart disease, in particular correlating clinical, coronarographic and scintigraphic findings. MATERIAL AND METHODS. During the biennium 1989-91 we have used the myocardial perfusion imaging with thallium 201 in 29 patients (20 male age ranging from 40 to 60 years) injecting 2 mCi at exercise peak with immediate planar mapping, followed by a second registration at rest 4 hours later (thallium 201). Imaging with 99mTc SESTAMIBI has been carried out in 6 patients (two of whom previously studied with thallium 201) injecting 20-22 mCi both at stress peak and at rest, with SPECT mapping 60'-90' later. All these patients presented specific problems for the diagnosis of myocardial ischemia. The exercise testing has been performed by a bicycle ergometer and with a standardized procedure increasing every two minutes the workload to the maximum tolerated according to the clinical conditions and to the response. All antianginal treatments were discontinued for at least 48 hours before testing and the patients were fasted for 6 hours. The images were obtained using a small field scintillation camera with a low-energy general purpose collimator. We divided the patients in 4 groups: Group A. Six patients who had an open heart operation: in 5 coronary revascularization was carried out (plus left ventricular aneurysmectomy in one and plus aortic valve replacement in another); in 1 patient an aortic valve replacement was performed on. Group B. Six patients have been evaluated after coronary angiography. Group C. Seventeen patients with doubtful diagnosis of myocardial ischemia on the base of the symptoms and/or non invasive testing as rest or stress electrocardiogram (ECG). Group D. In 6 more patients (2 of those previously studied with thallium 201) the myocardium has been assessed with SESTAMIBI. RESULTS. In one patient of the group A the thallium 201 images detected silent ischemia; in 5 removed the diagnostic doubts of the ECG findings owing to left ventricular overload or to old infarctions in 2 patients and to electrolytes disturbances or pharmacological effects in 3 patients. In group B patients the thallium 201 further on could assess the extent of ischemic and necrotic areas suggesting the final indications to angioplasty in 3 patients, medical treatment in 2 and surgery in 1. We could not find correlations between the extent of the disease predicted by the coronarography and the findings of the thallium 201 images. In the diagnosis of myocardial ischemia, group C, the Thallium 201 has been very useful and specific excluding an ischemic origin in 4 patients with arrhythmias, in 2 patients without symptoms of angina but with doubts at rest and exercise ECG findings and in 4 with atypical thoracoalgia and doubtful ECG. On the contrary, this test could give the final diagnosis of ischemia in 6 patients displaying its sensitivity in detecting coronary artery disease. Among the patients assessed with SESTAMIBI, in 2 this test has been essential in evaluating the myocardial contractility and the segmental wall motion. DISCUSSION. The usefulness of Thallium 201 imaging, as a very sensitive mean in detecting coronary artery disease and in the assessment of myocardial viability, is well known. Although the most common indications of this technique are well standardized, in the clinical practice there are many situations in which the thallium 201 can contribute to the diagnosis and to the management. (ABSTRACT TRUNCATED)

Thallium-201: what do we gain from new clinical protocols and acquisition procedures? The Italian Study on Thallium Reinjection/SIRT)

Nine medical centers, equipped with the same gamma camera and computer software, participated in this multicenter study on thallium-201 reinjection imaging. Preliminary findings for the first 143 patients with ischemic heart disease and perfusion defects at stress imaging are reported. Eighty-eight patients were reinjected at rest after conventional stress-redistribution imaging. Another 55 patients were reinjected at rest on a separate day. After segmental comparison of conventional redistribution versus stress imaging, differences > 1 in the segmental scores on a reduced 3 point scale identified 58 patients with irreversible or mainly irreversible defects (dominant scar pattern) and 85 patients with reversible or mainly reversible defects (dominant ischemic pattern). When reinjection was compared to stress images, 24 patients out of 58 with a dominant scar pattern at the conventional analysis were then assigned to the group with a dominant ischemic pattern. No clinical variables or exercise stress data were found to be significantly different in this patient subgroup. Only 4 out of 85 patients with a dominant ischemic pattern were reassigned to a dominant scar pattern after reinjection scoring. These preliminary results of the SIRT study confirm the consistent problem of scar overestimation by conventional stress-redistribution imaging and the clinical value of the thallium-201 reinjection procedure for differentiating viable from necrotic myocardium.

Different effects of metoclopramide and domperidone on GH release in type I male diabetics

Dopamine (DA) has a physiological role in the control of GH release from the pituitary. Studies have been carried out using DA agonist or antagonist, since in normal subjects DA does not cross the blood-brain-barrier (BBB). In contrast, the BBB is altered in type I diabetics, who respond to DA with a significant increase of GH release. In these patients Metoclopramide (MCP), an antidopaminergic drug, is also capable of stimulating GH release. In a previous paper, we suggested that this effect could be related to enhanced blood concentrations of DA, due to a reduced peripheral DA catabolism determined by MCP. However, since MCP crosses the BBB, an effect of this drug on other hypothalamic neurotransmitters could not be excluded. The purpose of the present study was to determine whether Domperidone (DOM) a drug which does not cross the BBB, but as well as MCP is thought to increase blood levels of DA, is also capable of inducing GH release in diabetics. Sixteen type I male diabetics were injected intravenously with MCP (6) or DOM (10) and a week later with normal saline. Ten normal subjects participated as controls to all three tests. MCP and DOM did not produce any effects in the normal controls; as expected, MCP induced a marked increase in serum levels of GH in the diabetics, while in contrast DOM did not stimulate GH secretion in diabetics. These data suggest that the effect of MCP is not due to the dopaminergic pathway previously described, but rather to a modulation of some other neurotransmitter at hypothalamic level, or to a direct effect on the pituitary in diabetics.