Risk Factors for Thyroid Cancer: What Do We Know So Far?

Thyroid cancer (TC) is the most common endocrine cancer today. The rising incidence of the differentiated papillary type cannot be entirely explained by early and meticulous diagnosis, since a proportion of large tumors has also been reported. In this review, we present the results of numerous investigations focused on possible factors causing increased TC incidence, such as chromosomal and genetic alterations, iodine intake, TSH level, autoimmune thyroid disease, gender, estrogen, obesity, lifestyle changes, and environmental pollutants. Up to now, only childhood exposure to ionizing radiation has been fully recognized as a risk factor. There is also a possibility that yet undiscovered carcinogens, especially during intrauterine life or early childhood, might be responsible for increased TC incidence as well as epigenetic changes. Therefore, more studies are necessary in order to further investigate the potential risk factors for TC and their mechanisms of action.

Predictive Value of Intraoperative Sentinel Lymph Node Imprint Cytology Analysis for Metastasis in Patients with Melanoma.

Since there are no standardized protocols regarding the detection of microscopic melanoma deposits in sentinel lymph nodes (SLN), the aim of this study was to present our experience with intraoperative cytological evaluation of SLN in patients with melanoma. The study included 475 SLN biopsies (SLNB) from 201 patients with primary cutaneous melanoma of intermediate thickness. Each lymph node was cut in half; touch imprint cytology (TIC) preparations of all cut surfaces were performed and stained according to a modified May-Grünwald-Giemsa method. The results were compared to definitive postoperative histology. Twenty of 25 SLNB positive on TIC proved to be metastatic when compared to definitive histology. Most of 32 SLN that were suspicious but not diagnostic on TIC were proven negative (23/32, 71.8%), while 7 nodes had metastases (one micrometastasis and one with isolated tumor cells only). The majority (94%) of SLNBs negative on TIC remained negative on final histology, while 6% or 25 nodes were positive, mostly with micrometastases or isolated tumor cells (17/25). In frozen sections performed in cases of suspicious or positive SLN cytology, metastasis was confirmed in 80% of positive and in 21.9% of suspicious TIC. Altogether, 49% (27/55) of positive SLNB were identified intraoperatively in 57% (24/42) of patients, and in those cases a complete regional lymph node dissection was performed in the first step. TIC assessment of SLNB with 99% specificity and 57% sensitivity for intraoperative identification of metastasis is useful and beneficial for avoiding a second operative procedure.

Glomus Tumor of the Neck Detected With 99mTc EDDA HYNIC-TOC.

A 54-year-old woman was referred to thyroid evaluation because of a lump on the left side of the neck. Ultrasound exam did not show any thyroid abnormality, but highly perfused nodule at the left common carotid artery bifurcation was found. Because of the specific location, somatostatin receptor scintigraphy with Tc EDDA HYNIC-TOC was performed, starting with perfusion images and followed with SPECT/CT imaging at 2 and 4 hours. Well-perfused nodule with intensive accumulation and no other visible pathology in the body raised suspicion of a glomus tumor, consistent with MR exam performed later. Subsequent surgical removal confirmed carotid paraganglioma.

Estimated collective effective dose to the population from nuclear medicine diagnostic procedures in Croatia: A comparison of 2010 and 2015.

OBJECTIVE: This study presents national surveys of patient exposure from nuclear medicine (NM) diagnostic procedures in 2010 and 2015 in the Republic of Croatia. METHODS: The survey was performed according to the European Commission Dose DataMed (DDM) project methodology. 28 most frequent NM diagnostic procedures were identified. Data about frequencies of procedures and average administered activities of radioisotopes used in those procedures were collected. Average administered activities were converted to effective doses according to the dose conversion coefficients. Then the collective effective dose to the population and an effective dose per capita were calculated based on the number of the most frequent NM diagnostic procedures and the average effective dose per procedure. RESULTS: In 2010, 41200 NM diagnostic procedures led to 146.7 manSv collective effective dose to the population and in 2015, 42000 NM diagnostic procedures led to 146.8 manSv collective effective dose to the population. The frequencies of NM diagnostic procedures were 9.7 and 9.8 annually per 1000 population with 34.1 µSv and 34.2 µSv effective dose per capita for 2010 and 2015, respectively. The main contributors to the annual collective dose from NM in Croatia are examinations of the bone, heart, thyroid and PET/CT tumour diagnostic. Average administered activities have not changed considerably from 2010 to 2015. Nevertheless, within the frequency of some of the procedures, significant changes were found in five-year period. CONCLUSIONS: Frequencies, average administered activities and collective effective dose to the population from NM diagnostic procedures in Croatia are comparable to the values reported by other European surveys. Changes were found between 2010 and 2015 and we intend to perform this study periodically to identify possible trends, but also to raise awareness about the potential dose optimization.

The evolvement of the renographic curve pattern in early childhood.

The purpose of this study was to evaluate renographic parameters obtained from healthy renal units (RUs) in newborns and infants with unilateral kidney condition. Thirty three children including twenty newborns, referred to Technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) diuretic scintigraphy due to unilateral kidney condition entered the study. Only contralateral, healthy RUs were analyzed. Since many children returned for follow up, there were altogether 78 dynamic studies included. Kidney length was compared to ultrasound measurements. Renographic curve parameters (time to maximum counts, T max and time to half maximum counts, T1/2 max) were evaluated. The results showed that the kidney length measured on Tc-99m MAG3 scintigraphy correlated well with ultrasound measurements. Regarding the renographic curve parameters, in the newborn period a significantly shorter T max (mean T max 3.65 +/- 1.2 min, p = 0.026) was found compared to the group of two months old infants (5.12 +/- 2.2 min). In older age groups mean T max gradually shortened again. On the contrary, T1/2 max was significantly longer in newborn and early infant period than in older age groups (16.7 +/- 8.2 min, p = 0.018), but generally showed variable values until the age of three years. It can be concluded that it is important to be aware of possible diversities of renographic curve pattern of healthy kidneys in early childhood, especially in the elimination part. Therefore, when interpreting a dynamic renal study, one should also consider other parameters like kidney growth, morphology and differential function, which can be reliably monitored with repeated Tc-99m MAG3 scintigraphy, to discern between normal and pathologic finding.

The renal parenchyma evaluation: MAG3 vs. DMSA.

Scintigraphy with Tc-99m dimercaptosuccinic acid (DMSA) is considered a reference method for assessment of parenchymal lesions and estimation of differential kidney function. The aim of study was to evaluate Tc-99m mercaptoacetyltriglycine (MAG3) dynamic renal scintigraphy for the same purpose. 188 patients, submitted to both studies within three months, were divided in two groups. In the first, 83 DMSA images were compared to parenchymal phase of MAG3 scintigraphy. Kidney morphology was independently evaluated by four observers. In the second group (N = 105), differential function was calculated in MAG3 and DMSA studies and the respective results were compared. Findings corresponded completely in 85% of patients. There were no statistically significant differences between calculated differential function on DMSA and MAG3 images. The results showed that most of parenchymal lesions detected on DMSA scans can be identified on MAG3 parenchymal scans. Both studies can be equally used for the calculation of differential kidney function.