Incidental thyroid lesions detected by FDG-PET/CT: prevalence and risk of thyroid cancer

BACKGROUND

Incidentally found thyroid lesions are frequently detected in patients undergoing FDG-PET/CT. The aim of this study was to investigate the prevalence of incidentally found thyroid lesions in patients undergoing FDG-PET/CT and determine the risk for thyroid cancer.

METHODS

FDG-PET/CT was performed on 3,379 patients for evaluation of suspected or known cancer or cancer screening without any history of thyroid cancer between November 2003 and December 2005. Medical records related to the FDG-PET/CT findings including maximum SUV(SUVmax) and pattern of FDG uptake, US findings, FNA, histopathology received by operation were reviewed retrospectively.

RESULTS

Two hundred eighty five patients (8.4%) were identified to have FDG uptake on FDG-PET/CT. 99 patients with focal or diffuse FDG uptake underwent further evaluation. The cancer risk of incidentally found thyroid lesions on FDG-PET/CT was 23.2% (22/99) and the cancer risks associated with focal and diffuse FDG uptake were 30.9% and 6.4%. There was a significant difference in the SUVmax between the benign and malignant nodules (3.35 +/- 1.69 vs. 6.64 +/- 4.12; P < 0.001). There was a significant correlation between the SUVmax and the size of the cancer.

CONCLUSION

The results of this study suggest that incidentally found thyroid lesions by FDG-PET/CT, especially a focal FDG uptake and a high SUV, have a high risk of thyroid malignancy. Further diagnostic work-up is needed in these cases.

Positron emission tomography-computed tomography in the detection of axillary lymph node metastasis in patients with early stage breast cancer

OBJECTIVE

The status of axillary lymph nodes (ALNs) is the most important prognostic factor in breast cancer. The purpose of this study was to evaluate the clinical usefulness of ALN involvement by means of positron emission tomography-computed tomography (PET-CT) compared with breast sonography and mammography in patients with early breast cancer.

METHODS

This study involved 108 breast cancer patients with non-palpable ALNs. All patients had PET-CT, breast sonography and mammography imaging before sentinel lymph node (SLN) biopsy. After SLN biopsy, all patients underwent complete ALN dissection. ALNs were evaluated by standard hematoxylin and eosin staining techniques. The findings of PET-CT, breast sonography and mammography imaging of 108 patients were compared with pathologic findings after surgery. Sensitivity, specificity and accuracy of individual diagnostic modalities were compared. Diagnostic accuracy was evaluated applying receiver operating characteristic (ROC) curve areas.

RESULTS

The sensitivity, specificity and accuracy of PET-CT imaging were 48.5%, 84% and 73.2%, respectively. The sensitivity, specificity and accuracy of breast sonography were 51.5%, 89.3% and 77.8%, respectively. The sensitivity, specificity and accuracy of mammography were 33.3%, 96% and 76.9%, respectively. For involvement of ALNs, PET-CT imaging, breast sonography and mammography had areas under the ROC curve of 0.662, 0.704 and 0.647, respectively.

CONCLUSIONS

Compared with the combination of breast sonography and mammography, PET-CT was less sensitive and had less accuracy in detecting ALN metastasis. Consequently, PET-CT is not a reliable non-invasive modality for assessing ALN involvement that can replace ALN dissection or SLN biopsy before decisions are made on appropriate systemic interventions.

p53 as a specific prognostic factor in triple-negative breast cancer

OBJECTIVE

A recent suggestion is that the predictive value of a single biomarker may rely on the genetic background on the tumor and that different breast cancer subgroups may have different predictive markers of response to chemotherapy. The prognostic value of p53 in the outcome of adjuvant anthracycline-containing chemotherapy was evaluated according to molecular subclasses defined using the expression of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2.

METHODS

Subjects were patients (n = 135) with invasive ductal carcinoma treated with adjuvant anthracycline-based chemotherapy between 1994 and 2000 in our hospital. Clinico-pathological features were reviewed by retrospective examination of medical records.

RESULTS

Overall survival rate was not independently predictive by p53 status (P = 0.182). However, in triple-negative cases, there was statistically significant survival difference (P = 0.034) and no statistically significant difference (P = 0.783) in non-triple-negative cases by p53 status. In the Cox proportional hazard analysis, p53 was also strongly predictive for relapse-free survival (P = 0.013) and overall survival (P = 0.049) in triple-negative patients.

CONCLUSIONS

p53 status could be a specific prognostic factor in triple-negative breast cancer patients treated by adjuvant anthracycline-based regimen. When p53 is positive in triple-negative breast cancer, we could expect poor survival, prompting aggressive or alternative treatment.

Endoscopic thyroidectomy and sentinel lymph node biopsy via an anterior chest approach for papillary thyroid cancer

The clinical role of endoscopic thyroidectomy and sentinel lymph node biopsy (SLNB) for differentiated thyroid cancer remains open to debate. Conventional thyroidectomy requires a cervical incision and often leaves an unsightly scar on the anterior neck. Endoscopic thyroidectomy is technically feasible and safe, with much better cosmetic results. The prognostic importance of lymph node metastasis in thyroid cancer makes central lymph node dissection a crucial option in thyroid cancer surgery. However, it is associated with an increased risk of complications such as recurrent laryngeal nerve injury or hypoparathyroidism, even in expert hands. Thus, the feasibility and future role of SLNB in thyroid cancer remains controversial. We describe our technique of performing endoscopic thyroidectomy with SLNB and central lymph node dissection via a gasless anterior chest approach for thyroid cancer.

Prognostic significance of HER2 gene amplification according to stage of breast cancer

It is well known that the amplification of the HER2 gene is closely associated with poor prognosis of breast cancer. However, there is controversy about the clinical significance of HER2 according to lymph node status in breast cancer. The aim of this study was to identify the differences in the prognostic significance of HER2 gene amplification according to the stages of breast cancer. We prepared a tissue array for fluorescence in situ hybridization (FISH) with breast cancer specimens from the surgery in 1994 to 1999. Total 338 cases of breast cancer were enrolled and the median follow-up period was 6.3 yr. The detection rates of HER2 gene amplification were as follows: 10.3% in stage I, 22.3% in stage II, and 43.8% in stage III. On survival analyses HER2-positive groups showed worse prognosis in stage III of breast cancer, but not in stage I or II. Multivariate analyses with a Cox-regression model also revealed that HER2 amplification was an independent prognostic factor only in stage III breast cancer. Regarding HER2 gene amplification as a prognostic factor of breast cancer, the clinical significance of the gene was found to be confined to advanced breast cancer.

Bilateral chylothoraces without chyle leakage after left-sided neck dissection for thyroid cancer: report of two cases

Bilateral chylothorax is a rare complication of neck dissection, but it is potentially serious and sometimes life threatening. Because of the rarity of chylothorax, surgeons are unfamiliar with its early signs, which allow a prompt diagnosis and effective management. Most cases reported in the literature were associated with a concurrent external chyle leakage, which occurred either during or after surgery. We report two cases of bilateral chylothoraces without concurrent external chyle leakage, which occurred after left-sided neck dissections for thyroid cancer. We treated both patients successfully with conservative management.

Oligonucleotide DNA chips are useful adjuncts in epigenetic studies of glioblastomas

Several studies have suggested that hypermethylation and hypomethylation of CpG islands within the promoters and 5' exons of tumor-related genes are closely associated with carcinogenesis. However, large-scale analysis of candidate genes has been hampered by the lack of a high throughput approach for analyzing methylation patterns. Using methylation-specific oligonucleotide (MSO) chips, we evaluated the methylation patterns of eight samples of fresh frozen glioblastoma tissue. The MSO chip used contained DNA probes with the CpG sites of p16 (p16INK4A, CDKN2A), MGMT (O6-Methylguanine-DNA-methyltransferase), APC (adenomatous polyposis coil), RASSF1A (human RAS effect homolog), which are usually hypermethylated in cancer cells and MAGE (melanoma antigen), which is usually hypomethylated in cancer cells. We selected CpG sites for analysis; 28 CpG sites (263 bp) for p16, 26 CpG sites (249 bp) for MGMT, 16 CpG sites (195 bp) for APC, 22 CpG sites (262 bp) for RASSF1A and 18 CpG sites (235 bp) for MAGE. We then constructed primer sets not including CpG sites. Bisulfite modification of genomic DNA, methylation specific PCR, hybridization and image scan with data analysis and sequencing of the bisulfite modified DNA were carried out. Of the eight glioblastomas, hypermethylation of the 5'-CpG sites of the MGMT were found in two, RASSF1A were found in five, and p16 and APC genes were not found in any cases and hypomethylation of that of the MAGE was found in eight cases. These results obtained from the oligo DNA chip study were correlated well with the sequencing data of bisulfite modified genomic DNA except in regard to the RASSF1A and MAGE genes. The devised MSO DNA chip is a useful tool for studies on methylation.

Ultrastructural studies of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract (GIT). Although interstitial cells of Cajal has been suggested as origin of this tumor, the cytological and ultrastructural features of GISTs are heterogeneous and unclear. A total 10 cases of normal gastrointestinal tissue (control), 13 GISTs of the stomach (8), small intestine (3), mesocolon (1) and liver (1), and 2 gastrointestinal autonomic nervous tumor (GANT) of small intestine were ultrastructurally studied. Normal interstitial cells of Cajal (ICC) were abundantly present around the myenteric plexuses or individually scattered through the wall of GIT. ICC was characterized by slender cytoplasmic processes, well-developed endoplasmic reticulum (ER), mitochondria, Golgi apparatus, caveolae and intermediate filaments. The GISTs and GANTs had overlapping ultrastructures. The most common and important ultrastructural features of GISTs were rich villous cytoplasmic processes, dispersed intermediate filaments and abundant SER, and those of GANTs were neurosecretory granules and skenoid fibers. Compared with ICC, the GISTs and GANTs had remarkably reduced caveolae and gap junctions. Our study suggested that ultrastructural analysis gives much information to investigate lineage differentiation of neoplastic cells and make a differential diagnosis of these tumors from other mesenchymal tumors and between GISTs and GANTs.