Prognostic Significance of 2-Deoxy-2-[18F]-Fluoro-D-Glucose PET/CT in Patients With Locally Advanced Esophageal Cancer Undergoing Neoadjuvant Chemoradiotherapy Before Surgery: A Nonparametric Approach.

To investigate the prognostic value of tumor metabolism measurements on serial 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography and computed tomography scans in patients with locally advanced esophageal cancer undergoing neoadjuvant chemoradiotherapy. Forty-five patients (63 ±â€Š7 years, 6 female) treated with concomitant chemoradiotherapy before surgery were followed up for 24 ±â€Š18 months (range 4-71). Positron emission tomography and computed tomography scans were obtained within 1 week before the start (PET1) and 1 month after the completion of the treatment (PET2). Total body tumor metabolic activity was measured as the sum of the parameters: SUVmax, SUV corrected for lean body mass, and total lesion glycolysis (TLG40/50/70%). Then, delta values for the parameters between PET1 and PET2 were calculated and expressed as percentage of PET1 results. At the time of the analysis, 27 patients were dead and 18 were alive. There was no difference between the 2 groups in terms of age, sex, site of the disease, histology, and the presence/absence of linfonodal metastases (P = NS). Survival random forest analysis (20,000 trees) resulted in an estimate of error rate of 36%. The nonparametric approach identified ΔTLG40 as the most predictive factor of survival (relative importance 100%). Moreover, T (17%), N (5%), and M (5%) stage of the disease, cancer histology (11%), TLG70 (5%) at the end of chemioradioterapy, and ΔTLG(50-70) (17%-5%) were positively associated with patient outcome. The nonparametric analysis confirmed the prognostic importance of some clinical parameters, such as TNM stage and cancer histology. Moreover, ΔTLG resulted to be the most important factor in predicting outcome and should be considered in risk stratification of patients treated with neoadjuvant chemoradiotherapy.

Evaluation of ischaemia in patients with atrial fibrillation: impact of stress protocol on myocardial perfusion imaging accuracy.

BACKGROUND: To evaluate the accuracy of myocardial perfusion imaging (MPI) on a novel cadmium-zinc-thelluride camera in detecting significant coronary artery disease (CAD) in patients with atrial fibrillation (AF). METHODS AND RESULTS: Seventy-four subjects with AF submitted to stress-rest MPI and coronary angiography were consecutively enrolled. One hundred and forty-eight patients in sinus rhythm, matched for age, sex, and type of stress-test protocol and with known coronary anatomy served as controls. The summed difference score, as measure of reversible myocardial ischaemia, was calculated. A coronary stenosis ≥70% was considered significant. The prevalence of significant CAD did not differ between AF patients and controls. At receiving operating characteristic analysis MPI showed relevant accuracy in unmasking the presence of significant CAD both in AF and in control patients (areas under the curve 0.71 vs. 0.80, P for difference: 0.212). However, after stratifying patients according to the stress protocol, a significant interaction between the presence of AF and MPI diagnostic power was evident. While in the case of a vasodilator stress-test MPI diagnostic accuracy remained high in both groups of patients (P for difference: 0.664), in those submitted to an exercise stress-test the diagnostic power of MPI was significantly lower in the presence of AF (P for difference: 0.039), because of a lower specificity. Interestingly, at multivariate analysis, a lower exercise duration (P = 0.017) was the major predictor of reduced MPI specificity. CONCLUSION: The presence of AF impairs MPI accuracy on the detection significant CAD. This effect was only apparent in the case of an exercise stress-test, while disappeared in patients submitted to vasodilator stress.