Positron emission tomography/computed tomography and esophageal cancer in the clinical practice: How does it affect the prognosis?

AIMS: The aim of this study was to assess the diagnostic value of positron emission tomography/computed tomography (PET/CT) in staging of esophageal cancer and to evaluate the prognostic role of metabolic parameters before and after neo-adjuvant treatment. SETTINGS AND DESIGN: Mono-institutional retrospective study. MATERIALS AND METHODS: We retrospectively evaluated 29 patients who underwent PET/CT at initial staging and after neo-adjuvant therapy. Metabolic parameters were calculated: mean, average, maximum standardized uptake value (SUVmax), and total lesion glycolysis (TLG). Diagnostic advantages of PET/CT over conventional imaging (CI) were determined. The relationships between baseline and after-therapy SUVmax and TLG, change in SUV and TLG (reported as ∆) for the primary tumor and prognosis were assessed. STATISTICAL ANALYSIS USED: Non-parametric statistic (e.g. Wilcoxon test and chi-square test). RESULTS: Twenty-nine patients were eligible for the initial staging. Thirteen patients were incorrectly staged based on CI; PET/CT was able to identify distant lymph nodes in seven patients (59%) and distant metastases in four (31%). The median SUVmax before and after neoadjuvant therapy was 10.38 and 3.53 (P = 0.0005), respectively. Only few semi-quantitative parameters obtained by PET/CT after neoadjuvant therapy seemed to have a prognostic value. TLG and ∆TLG were significantly different between disease-free and died patients (0.49 versus 15.51 and 100% versus 94%, respectively; all P = <0.05). CONCLUSIONS: PET/CT is confirmed as being able to detect distant metastases and to avoid unnecessary surgery. Although not routinely reported, post-neoadjuvant TLG and ∆TLG might be considered as useful prognostic parameters and should be further evaluated prospectively.

Prospective assessment of imaging after preoperative chemoradiotherapy for rectal cancer.

BACKGROUND: The aim of the study was to assess the accuracy of imaging techniques in predicting pathologic tumor (ypT), node (ypN) stages and the circumferential resection margin (ypCRM) status of rectal cancers after preoperative chemoradiotherapy (CRT). METHODS: Using pelvic computed tomography (CT), magnetic resonance imaging (MRI), and endorectal ultrasound (ERUS), 90 consecutive patients with locally advanced mid-to-low rectal cancer were prospectively assessed. Postirradiation T and N stages and infiltration of the CRM, as assessed by CT, MRI and ERUS, were compared with histopathologic findings. RESULTS: The accuracy of ypT staging was low, whatever the imaging technique used (37% by CT, 34% by MRI, and 27% by ERUS), the most frequent inaccuracy being overstaging. Imaging showed a good specificity and good negative predictive values (NPV) when mural staging was grouped into ypT ≤ 3 and ypT4 categories; in particular, ERUS achieved a 92% specificity and 95% NPV. CRM involvement was correctly predicted in 71% of patients by CT (74% specificity; 93% NPV) and in 85% by MRI (88% specificity; 95% NPV). The accuracy for nodal staging was 62%, 68%, and 65% by CT, MRI and ERUS, respectively; the corresponding NPV were 88%, 78%, and 76%. CONCLUSION: Current imaging techniques are inaccurate in restaging rectal cancer after CRT but are useful in predicting T ≤ 3 tumors, cases with negative nodes and tumor-free CRM. These findings may be of clinical relevance for planning less invasive surgery.

Error count of radiopaque markers in colonic segmental transit time study.

OBJECTIVE: The objective of our study was to evaluate the feasibility and efficacy of a radiologic technique in increasing colon visibility in colonic transit time studies. Three radiologists counted segmental colonic radiopaque markers in two patient groups, based on classic criteria in the first group and also on a colonic barium trace in the second. Agreement between marker counts was assessed using method comparison analysis. CONCLUSION: With the barium trace technique, the anatomic conspicuity of colonic segments is improved, a correct segmental marker count can be obtained, and colonic inertia can be more easily distinguished from distal constipation.