Comparison of 18F-FDG PET/CT and DW-MRI in assessment of neoadjuvant radiochemotherapy response in locally advanced rectal cancer patients. / Comparación de la PET/TC 18F-FDG y la DW-MRI en la evaluación de la respuesta a la radioquimioterapia neoadyuvante en pacientes con cáncer rectal localmente avanzado.

OBJECTIVE: Our aim is to evaluate if different metabolic parameters obtained by 18F-FDG PET/CT and diffusion weighted magnetic resonance imaging (DW-MRI) can aid in neoadjuvant radiochemotherapy (RCT) response assessment in locally advanced rectal cancer (LARC) patients. METHODS: Out of 20 LARC patients, who were planned to receive neoadjuvant RCT, 19 were included in this prospective study. Patients had 18F-FDG PET/CT and DW-MRI at initial staging, interim (2 weeks after onset of RCT) and after completion of RCT (post-therapy). Standardized uptake value (SUV) parameters (SUVmax, SUVmean, SUVpeak, SULpeak), metabolic tumor volume (MTV) and tumor lesion glycolysis (TLG) detected on PET images and apparent diffusion coefficient (ADC) values (for b=400 and b=1000s/mm2) obtained from DW-MRI were recorded. Postoperative tumor regression grade (TRG) was used as gold-standard, except for 2 patients who were under complete remission with non-operative management 19 months post-therapy and scored as responders. RESULTS: On interim PET/CT, no significant difference was found among PET parameters between responders and non-responders, whereas post-therapy SUVmax, SUVpeak, MTV, SULpeak, TLG (P=0.02, P=0.014, P=0.025, P=0.007, P=0.02, respectively) and initial MTV (P=0.034) were significantly lower in responders. ADC response index (RI) was higher in responders (interim P=0.026; post-therapy: P=0.018) and ROC analysis revealed that a threshold of ADC RI>41.6% for interim MRI and >44.6% for post-therapy MRI had sensitivity and specificity of 75.0% and 90.9%, respectively. CONCLUSIONS: While interim 18F-FDG PET/CT failed to predict therapy response during RCT, post-therapy PET could accurately differentiate responders. DW-MRI was found to be more promising in interim detection of RCT response.

Erratum:Preoperative neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio as new prognostic factors for patients with colorectal cancer.

In this article published in Volume 21, issue 5, the authors' names appeared in the Pubmed abstract as: "Mahsuni Sevinc M, Riza Gunduz U, Kinaci E, Armagan Aydin A, Bayrak S, Umar Gursu R, Gunduz S". The correct authors' names are: "Sevinc MM, Gunduz UR, Kinaci E, Aydin AA, Bayrak S, Gursu RU, Gunduz S" This error appeared only in the PubMed database and not in the print form of the Journal.

The effect of icodextrin and glucose-containing solutions on insulin resistance in CAPD patients.

PURPOSE: Peritoneal dialysis patients have particular risks with respect to their lipid status and hyperinsulinemia. The aim of this study was to investigate the relation between insulin resistance and the type of the peritoneal dialysis solution. MATERIALS: 41 randomly selected non-diabetic patient cohort who were already under treatment with continuous ambulatory peritoneal dialysis (CAPD) and 10 healthy controls participated in the study. 24 of the 41 patients were using 3 standard 1.36% glucose solutions during the day and 1 hypertonic solution with 2.27% glucose dwell during the night (glucose group: mean age 45.54 +/- 16.67 years and median CAPD duration 16.5 months). The remaining 17 patients were using 3 standard 1.36% glucose solutions during the day and 1 icodextrin dwell during the night for 8-10 hours (icodextrin group: mean age 47.47 +/- 13.15 years, median duration of icodextrin use 6 months (range 2-20 months), and median CAPD duration 30 months). Insulin resistance (IR) was calculated according to the homeostasis model assesment (HOMA) formula: HOMA-IR = fasting glucose (mmol/l) x fasting insulin (microU/1/22.5. The HOMA cutoff point for diagnosis of insulin resistance was established with receiver-operating characteristic (ROC) curves. The patients were called HOMA-IR(+) if their HOMA scores were higher than cutoff value. RESULTS: There were no significant differences between age, BMI, triglyceride, total and high-density lipoprotein (HDL) cholesterol, iron and ferritin, alanine aminotransferase, fibrinogen, intact parathyroid hormone, magnesium, hemoglobin and hematocrit levels of the 2 groups. The mean glucose levels of the groups were not different but fasting insulin levels and HOMA scores of the icodextrin group were significantly lower than the glucose group (10.15 +/- 6.87 vs. 18.11 +/- 13.15, p = 0.028, and 2.28 +/- 1.67 vs. 4.26 +/- 3.27, p = 0.027, respectively). The ratio of patients with low HOMA scores (cutoff = 2.511) were significantly higher in the icodextrin group than in the glucose group (71% vs 38%, p = 0.037). Other than fasting insulin and glucose levels, significantly positive correlation was found between HOMA score and BMI in both groups. With regression analysis, we found that the main parameters effecting HOMA score were BMI (p = 0.008) and triglyceride (p = 0.029) in the glucose group, but no parameters were found to affect HOMA score in icodextrin group. CONCLUSION: These results suggest that insulin resistance is reduced in peritoneal dialysis patients using icodextrin-based dialysis fluid instead of glucose-based dialysis fluid.