DIAGNOSTIC ROLE OF FLUORINE-18 (18F) FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY COMPUTED TOMOGRAPHY IN DETECTING RECURRENT DISEASE IN PATIENTS WITH COLORECTAL CANCER AND ELEVATED CARCINOEMBRYONIC ANTIGEN.

INTRODUCTION: Early detection of recurrence is an important factor for long term survival of patients with colorectal cancer. Measurement of serum levels of carcinoembryonic antigen has been commonly used in the postoperative surveillance of colorectal cancer. The purpose of this study was to evaluate the ability of positron emission tomography-computed tomography to detect pathological substrate of elevated serum carcinoembryonic antigen in patients with colorectal cancer. MATERIAL AND METHODS: The patients with colorectal cancer who underwent curative surgical resection and/ or chemotherapy, who were found in our database, were analyzed retrospectively. Forty-eight 18F-fluorodeoxyglucose positron emission tomography-computed tomography studies including 45 patients (14 women, 31 men; mean age: 62.93 years) with elevated serum, carcinoembryonic antigen levels, which had been performed between January 2011 and January 2014, were evaluated. Serum levels of carcinoembryonic antigen were measured within 3 months after positron emission tomography-computed tomography examination. Final diagnosis of recurrence was made by histopathological findings, radiology studies or clinical follow-up. RESULTS: Recurrences were diagnosed in 37 patients, the prevalence being 77.1%. Liver metastases were found in 18 patients, abdominal, pelvic and/or mediastinal lymph nodes were positive in 19 patients, 11 patients had loco regional recurrences and 4 patients had pulmonary metastasis, and bone metastases were found in one patient. One patient was diagnosed with metastasis in scar tissue. The overall sensitivity and specificity of positron emission tomography-computed tomography was 90.24% and 71.42%, respectively. The positive and negative predictive values were 94.87% and 55.56%, respectively. CONCLUSION: 18F-fluorodeoxyglucose positron emission tomography-computed tomography is a powerful tool that could be used in determining colorectal cancer recurrence in patients with elevated carcinoembryonic antigen levels and could have an important clinical impact on the management in patients with suspected recurrent colorectal cancer.

RELIABILITY OF POSITRON EMISSION TOMOGRAPHY-COMPUTED TOMOGRAPHY IN EVALUATION OF TESTICULAR CARCINOMA PATIENTS.

INTRODUCTION: The study was aimed at assessing the reliability of 18F-fluorodeoxyglucose positron emission tomography-computed tomography scan in evaluation of testicular carcinoma patients. MATERIAL AND METHODS: The study sample consisted of 26 scans performed in 23 patients with testicular carcinoma. According to the pathohistological finding, 14 patients had seminomas, 7 had nonseminomas and 2 patients had a mixed histological type. In 17 patients, the initial treatment was orchiectomy+chemotherapy, 2 patients had orchiectomy+chemotherapy+retroperitoneal lymph node dissection, 3 patients had orchiectomy only and one patient was treated with chemotherapy only. Abnormal computed tomography was the main cause for the oncologist to refer the patient to positron emission tomography-computed tomography scan (in 19 scans), magnetic resonance imaging abnormalities in 1 scan, high level oftumor markers in 3 and 3 scans were perforned for follow-up. Positron emission tomography-computed tomography imaging results were compared with histological results, other imaging modalities or the clinical follow-up of the patients. RESULTS: Positron emission tomography-computed tomography scans were positive in 6 and negative in 20 patients. In two patients, positron emission tomography-computed tomography was false positive. There were 20 negative positron emission omography-computed tomography scans perforned in 18 patients, one patient was lost for data analysis. Clinically stable disease was confirmed in 18 follow-up scans performed in 16 patients. The values of sensitivty, specificity, accuracy, and positive- and negative predictive value were 60%, 95%, 75%, 88% and 90.5%, respectively. CONCLUSION: A hgh negative predictive value obtained in our study (90.5%) suggests that there is a small possibility for a patient to have future relapse after normal positron emission tomography-computed tomography study. However, since the sensitivity and positive predictive value of the study ire rather low, there are limitations of positive positron emission tomography-computed tomography scan to suggest persistent disease.

Recurrent disease in juvenile differentiated thyroid carcinoma: prognostic factors, treatments, and outcomes.

UNLABELLED: The overall prognosis in pediatric differentiated thyroid carcinoma (DTC) is excellent. Recurrent disease is frequent, however, and requires additional treatment. We analyzed the probability of recurrence, prognostic factors, treatment, and outcome of juvenile DTC. METHODS: Fifty-one DTC patients (32 girls and 19 boys; ≤ 20 y old; mean age, 16.5 y) were treated with (131)I (radioiodine, or radioactive iodine [RAI]); the median follow-up was 10 y. Patients underwent different initial treatments: 46 patients received total thyroidectomy and RAI, 3 patients received total thyroidectomy, and 3 patients received subtotal thyroidectomy. The probability of recurrence and prognostic factors were tested with the Kaplan-Meier method. RESULTS: Initially, 36 of 51 patients achieved complete remission, 14 of 51 achieved partial remission, and 1 of 51 had progressive disease. By the follow-up, 11 of 51 patients (21.6%) had developed recurrent disease; the median appearance time was 4 y (range, 1-15 y). The probabilities of recurrence were 16.7% at 5 y, 22.3% at 10 y, and 33.3% at 15 and 23 y after the initial treatments. Factors that were strongly predictive of recurrence were age (P = 0.001), initial treatment (P = 0.0001), and tumor multifocality (P = 0.011). Sex, nodal metastases at presentation, distal metastases at presentation, histologic type of the tumor, T stage, and clinical stage had no influence on relapse (P = 0.180, P = 0.786, P = 0.796, P = 0.944, P = 0.352, and P = 0.729, respectively). Patients with recurrent disease, partial remission, and progressive disease were retreated, with either surgery or surgery and RAI, receiving cumulative activities of up to 40 GBq. The overall outcome in our patients was excellent: 90.2% complete remission, 3.92% partial remission, 1.96% stable disease, 1.96% disease-related death, and 1.96% another cause of death. CONCLUSION: Younger age at diagnosis, less radical primary surgery without subsequent RAI, and tumor multifocality are factors that are strongly prognostic for recurrence. For reducing the rate of relapse and improving surveillance for recurrent disease, total thyroidectomy followed by RAI appears to be the most beneficial initial treatment for patients with juvenile DTC. The use of RAI seems to be safe, with no adverse effects on subsequent fertility and pregnancy or secondary malignancy.

Lung tumors: early and delayed ratio of 99mTc-methoxy-2-isobutylisonitrile accumulation.

BACKGROUND/AIM: Currently used radiopharmaceuticals are nonspecific and most of them are accumulated by benign tumors as well as inflammatory lesions, abscess or granulomatous lesions. Some factors such as the choice of radiopharmaceutical applied, histopathologic type of tumor, its size, location or previous tumor treatment could influence tumor imaging sensitivity. The aim of this study was to investigate accumulation of 99mTc-methoxy-2-isobutylisonitrile (99mTc-MIBI) by counting early/delayed uptake and release of this radiopharmaceutical inside lung tumors and evaluating possible factors which could be involved in its accumulation. METHODS: Two-phase 99mTc-methoxy-2-isobutylisonitrile single photon emission computed tomography scan (early and delayed scan) was performed in 60 patients with lung tumors (the group 1 - 30 benign, and the group 2 - 30 malignant tumors). We calculated the uptake ratio on early (early ratio - ER), delayed images (delayed ratio - DR) and retention index (RI). Individual influence of etiology, diameter, localization, and histological type on uptake/release values was evaluated with regression analysis. RESULTS: The values of ER and DR were significantly different in both groups (p < 0.01), showing lower values in benign vs malignant lung tumors (ER 1.36 ± 0.094 and DR 1.25 ± 0.089 vs ER = 1.93 ± 0.106 and DR = 1.7 ± 0.095 respectively). Tumor size showed a significant influence on the change of ER and DR values (p < 0.01), with greater uptake in tumors > 3 cm. RI values showed no significance between the two groups (P > 0.05). CONCLUSION: The uptake ratio of 99mTc-methoxy-2-isobutylisonitrile could be a useful index in differentiating lung tumors, while RI has no influence on this. Among the evaluated factors, ER and DR values are significantly influenced only by the diameter of lung tumor, while localization or different histological types between the groups has no influence on this.

Lung 99mTc-MIBI scintigraphy: impact on diagnosis of solitary pulmonary nodule.

Most of today available non-invasive procedures cannot clearly determinate between benign and malignant solitary pulmonary nodules (SPN). The purpose of the study was to assess the possibility of using 99mTc labeled hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) to differentiate benign from malignant SPN. Sixty patients were included in the study if the CT scan showed indeterminate SPN. Prior to definitive diagnosis 99mTc-MIBI single photon emission computerized tomography (SPECT) was performed: early scan 10 minutes and delayed 60-120 minutes after the intravenous injection of 740 MBq 99mTc-MIBI using dual-headed Gamma camera. The results were considered positive if there was an increased accumulation of the radiopharmaceutical in the area of the lung corresponding to the location of the lesion. The mean nodule size ± SD measured on CT scan was 2.96 cm. Lung cancer was diagnosed in 30/60 patients (14 squamocellular, 10 adenocarcinoma, 3 large-cell and 3 microcellular lung carcinomas). Of the 30 patients with malignant lesions, 27 patients (90%) had positive 99mTc-MIBI scan results by qualitative assessment. Among benign lesions, 23/30 (76.7%) were negative on 99mTc-MIBI scan. The size and PH report of SPN is statistically significantly influencing on 99mTc-MIBI accumulation in the SPN (p<0.01). The sensitivity, specificity, accuracy, positive and negative predictive value were 90%, 76.6%, 79.4%, 88.5% and 83.3% respectively. 99mTc-MIBI SPECT is an inexpensive non-invasive diagnostic procedure which might be useful diagnostic modality in the evaluation of SPN. Easy availability and low cost makes 99mTc-MIBI SPECT an attractive method in evaluating SPN.