The value of 18FDG PET/CT parameters, hematological parameters and tumor markers in predicting KRAS oncogene mutation in colorectal cancer.

OBJECTIVE: In this study we investigated the predictive value of maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), neutrophils/lymphocytes ratio (NLR), platelets/lymphocytes ratio (PLR), carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9) in the prediction of KRAS gene mutation which plays an important role in the choice of treatment in colorectal cancer patients. SUBJECTS AND METHODS: A total of 55 cases with untreated colorectal cancer who had undergone both PET/CT examinations for initial staging and also mutation analysis of KRAS oncogene were studied. Fluorine-18-FDG PET/CT parameters (SUVmax, MTV, TLG), hematological parameters (NLR, PLR), and tumor markers (CEA, CA 19-9) were recorded and the relationship between these parameters and KRAS oncogene mutation was evaluated using receiver operating characteristics (ROC) analysis and multiple logistic regression analysis. RESULTS: In 20 cases mutations in the KRAS gene were detected, while in 35 cases mutations were not observed (wild-type). ROC analysis revealed that SUVmax, MTV, TLG, NLR, PLR, and CA 19-9 could not predict mutations in KRAS oncogene (P=0.600, 0.263, 0.214, 0.057, 0.104, 0.189, respectively) although CEA value showed signi..cant difference (P=0.031) but without high value of the area under the curve (0.676). Multivariate logistic regression analysis also did not show significant association between KRAS gene mutations and SUVmax, MTV, TLG, NLR, PLR, CEA, CA 19-9 values. CONCLUSION: We observed that in patients with colorectal cancers, we cannot predict KRAS gene mutations using PET/CT parameters (SUVmax, MTV, TLG), hematological parameters (NLR, PLR) or tumor marker CA 19-9. We detected a significant but not very strong association only between CEA and KRAS mutations.

Role of Tc-99m pertechnetate for remnant scintigraphy, post-thyroidectomy, and serum thyroglobulin and antithyroglobulin antibody levels in the patients with differentiated thyroid cancer.

AIM: Postoperative scanning may help to identify patients with differentiated thyroid cancer (DTC); however, low dose I-131 can lead to stunning and suboptimal response to ablative therapy. The aim of this retrospective study is to compare postablative I-131 scintigraphy with post-thyroidectomy Tc-99m pertechnetate scintigraphy, serum thyroglobulin (Tg) and antithyroglobulin antibody (TgAb) levels in patients with DTC. METHODS: Patients who had undergone surgical thyroidectomy for DTC were evaluated retrospectively. All patients had undergone Tc-99m pertechnetate and postablative I-131 scans. Serum Tg and TgAb levels were measured in all subjects. Preablative pertechnetate scans of the thyroid bed were viewed blindly and then directly compared with postablative I-131 scans and Tc-99m pertechnetate scintigraphy was compared with serum Tg and TgAb levels. RESULTS: One hundred and seventy-four patients (146 women, 28 men) with a mean age of 48.7 ± 13.1 (range 12-84) years who had undergone surgical thyroidectomy for DTC were evaluated retrospectively. Of 174 patients, 6 (3%) had negative I-131 and also Tc-99m pertechnetate scintigraphy results. Of the remaining 168 positive I-131 scans, 131 (75%) were positive in at least one site on the pertechnetate scan, 19 (11%) were considered to have equivocal uptake and 18 (11%) were negative. For the per-site analysis, pertechnetate sites were considered to be accurately determined if they showed concordant uptake at sites that correlated precisely with those seen on the postablation I-131 scans. There were a total of 356 positive foci on I-131 scans. Of these, 273 foci (77%) were unequivocally positive on pertechnetate scintigraphy, 41 (11%) showed equivocal uptake and 42 (12%) foci could not be detected. There were statistically significant differences (p < 0.0001) between the negative and positive foci in terms of Tg levels on pertechnetate sites. CONCLUSIONS: A positive pertechnetate scan is, therefore, sufficient to guide progression to I-131 ablation in most patients. Pertechnetate scintigraphy may be of particular benefit if it is considered desirable to avoid use of I-131 in post-thyroidectomy remnant imaging. Tg level is an important parameter in the detection of remnant thyroid tissue in patients with DTC.

Comparison of Cystatin C and ß-Trace Protein Versus 99mTc-DTPA Plasma Sampling in Determining Glomerular Filtration Rate in Chronic Renal Disease.

UNLABELLED: Glomerular filtration rate (GFR) is the best indicator of renal function. The gold standard for GFR measurement is inulin clearance. However, its measurement is inconvenient, time-consuming, and costly. Thus, in both scientific studies and routine clinical practice nuclear medicine methods ((99m)Tc-diethylenetriaminepentaacetic acid [(99m)Tc-DTPA] and (51)Cr-ethylenediaminetetraacetic acid [(51)Cr-EDTA]) are preferred, and they correlate strongly with inulin clearance. In addition, cystatin C and ß-trace protein have also recently been used for this purpose. In the literature, however, data are limited about the clinical value of cystatin C and ß-trace protein in GFR measurement in chronic renal disease (CRD), and the results have been inconclusive. In this study, we aimed to determine the efficiency of cystatin C and ß-trace protein in the determination of GFR in CRD patients. METHODS: Eighty-four patients with CRD were included in the study (59 men and 25 women; age range, 21-88 y; mean age, 61 y). GFR was calculated using the gold-standard (99m)Tc-DTPA 2-sample plasma sampling method (TPSM) and 2 alternative methods: a formula using cystatin C and a formula using ß-trace protein. The correlation between TPSM and the cystatin C and ß-trace protein methods was assessed, and Bland-Altman analysis was used to graph scatterplots of the differences at a confidence interval of 95% (mean difference ± 1.96 SDs). RESULTS: GFRs calculated using both alternative methods correlated strongly with those calculated using the gold standard. However, the correlation was stronger for the cystatin C method than for the ß-trace protein method, and neither method produced reliably consistent GFRs. CONCLUSION: This study demonstrated that cystatin C and ß-trace protein do not reflect GFR with sufficient accuracy.

Evaluation of factors affecting tumor response and survival in patients with primary and metastatic liver cancer treated with microspheres.

OBJECTIVE: Radioembolization with the yttrium-90 (Y-90) microspheres is being used increasingly more often in the treatment of patients with primary or metastatic liver cancer. Although technetium-99m macroaggregated albumin (Tc-99m MAA) scintigraphy performed following diagnostic angiography has an important role in predicting the effectiveness of treatment and in dose estimation, the number of studies using quantitative assessment of Tc-99m MAA scintigraphy is limited in this field. In the present study, the aim was to assess whether a tumor dose is required to obtain objective tumor response and to check whether this threshold value is predictive in terms of tumor response, survival, and liver toxicity by using Tc-99m MAA single-photon emission computed tomography (SPECT) images. MATERIALS AND METHODS: Overall, 54 patients (20 women and 34 men; median age: 60 years) who underwent Y-90 Resin (SIR-Spheres) and Glass (TheraSphere) microsphere treatment with a diagnosis of unresectable liver cancer between August 2010 and April 2013 were included in the study. The mean doses to normal liver and tumor were estimated for each patient using Tc-99m MAA SPECT images and the medical internal radiation dosimetry method. The responses were assessed according to Response Evaluation Criteria In Solid Tumors (RECIST) and European Organisation for Research and Treatment of Cancer (EORTC) criteria. Kaplan-Meier survival curves and univariate Cox regression analysis were used in survival analysis. The relationship between treatment response and other parameters included was assessed using logistic regression analysis. The variables with a P value less than 0.01 in univariate analysis were assessed with multivariate analysis. RESULTS: Fifty-four Y-90 microsphere treatments (eight by using a Y-90 glass microsphere and 46 by using a Y-90 resin microsphere) were performed. In the multivariate analysis, the only parameter related to response was tumor dose (P<0.01). With a tumor dose of 280 Gy or higher, objective tumor response was observed in 59 and 77% of the patients according to RECIST and EORTC criteria, respectively, and the tumor control rate was found to be 95% according to both criteria. In addition, it was found that only tumor dose was correlated with progression-free survival (PFS) (P<0.001) and overall survival (OS) (P=0.018). When the tumor dose was 280 Gy or higher, median PFS increased from 2 to 10.7 months (P<0.001), whereas median OS increased from 9 to 17.6 months (P=0.018). However, reversible ≥ G2 liver toxicity was observed in 3.7% (2/54) of the patients within 3 months after radioembolization with a median normal liver dose of 40 Gy (10-102 Gy). There was reversible ≥ G3 liver toxicity in 3.7% (2/54) of patients, but no G4 liver toxicity was observed. Clinical radiation hepatitis and treatment-induced liver failure were not observed in any of these patients. CONCLUSION: Tc-99m MAA SPECT has a predictive value in terms of response to radioembolization, PFS, and OS. Dosimetry based on Tc-99m MAA SPECT images can be used in the selection of patients and, in particular, to adaptation of treatment plan in selected patients.

Measurements of tumor size using CT and PET compared to histopathological size in non-small cell lung cancer.

PURPOSE: In this study, we aimed to compare the tumor sizes determined by maximum morphological computed tomography (CT) and functional positron emission tomography (PET) with the histopathological size to determine which method provides the best correlation with the histopathological size in lung carcinoma patients. MATERIALS AND METHODS: Forty lung carcinoma patients (39 males, one female) diagnosed histopathologically from surgical resection materials were included in this retrospective study. The mean age (±standard deviation, SD) of the patients was 67.8±10.3 years with a range of 44 to 81 years. The PET scans were performed within the same week as the CT scan. In the CT scans, the morphological tumor sizes were measured three-dimensionally by the longest transaxial section in the parenchymal and mediastinal screening window. The functional tumor sizes were also measured three-dimensionally in the PET scans. These two measurement values were compared with the histopathological size using Bland-Altman plotting. Bland-Altman plotting was also performed to define the 95% limits of agreement, which was presented as the bias ±1.96 SD. RESULTS: The histopathological sizes were measured in a range of 1.2 to 7.5 cm. The maximum measurement of the tumors on the CT scans showed a lower concordance (mean difference, -0.30) than that obtained from PET, and the SD was found to be larger than the PET (1.96 SD was 3.50 for CT and 2.50 for PET). CONCLUSION: The PET measurements of tumor size were more compatible with the histopathological sizes than the CT measurements in patients with non-small cell lung cancer.