Abstract
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Purpose: BACKGROUND AND AIM: Preoperative staging is crucial for treatment planning in patients with adenocarcinoma of the esophagus (EAC). In particular, according to the EAC clinical staging (cStaging), there is an increasing interest for N-descriptors prior to surgery based on detection of single lymphatic stations (N). However, up to now, no specific data are available on the diagnostic performance of commonly used imaging modalities, such as CT, PET and EUS, in this context. The aim of the present multicentric study was to investigate the sensitivity/specificity of CT, PET and EUS for the preoperative assessment of lymph node metastases (LNM) based on single thoracic/abdominal N-descriptors in a cohort of patients with Siewert type I/II EAC submitted to primary resection. MATERIAL & METHODS: A consecutive series of 101 patients affected by Siewert type I/II (n=60/41) EAC included in two prospective trials performed in the University Hospital of Bologna (n=54) and Helsinki (n=47) was analyzed. Patients (M:F=75:26; mean age 65 years) underwent preoperative staging with thoracic-abdominal CT (with contrast medium), PET/CT and EUS (Endoscopic UltraSonography). Upfront surgery (no adjuvant therapy) was in indicated up to T4a (diaphragm), N+ (peri tumoral stations) and M0 tumors. Resected lymphatic nodes (LNY) and lymphatic metastases (LNM) were reported for the following stations: A) right paratracheal/sub-carinal/pulmonary ligament; B) paraesophageal thoracic; C) pericardial; D) left gastric artery, lesser curvature; E) celiac trunk, hepatic/splenic artery. Histopathological results were compared with clinical N-descriptors on CT, PET and EUS findings to assess sensitivity and specificity for each imaging modality.
Results: Overall, we operated 82 intestinal (81.2%), 12 diffuse (11.9%) and 7 other adenocarcinomas types (6.9%). LNY were 2451, with a median number of 23 lymph nodes per patient (IQR 14.2-32.7). A total number of 273 lymph nodes (4.1%) were positive histologically. Overall accuracy per patient was 62.3% for CT, 64% for PET, and 69.2% for EUS. Our data revealed an overall sensitivity and specificity of 39% and 86% for CT, 30% and 98% for PET, and 50% and 81% for EUS, respectively. EUS sensibility resulted higher compared to CT and PET in almost all nodal stations: 88%, 80%, 29%, 33%, 33%, respectively, compared to 58%, 33%, 47%, 24%, and 13% for CT and 7%, 20%, 24%, 21%, 6% for PET in the thoracic, para-esophageal, para-cardiac, left gastric artery/lesser curvature, celiac trunk/hepatic and splenic artery regions, respectively. Instead, EUS specificity resulted superimposable: 89%, 87%, 88%, 96%, and 86%, respectively, compared to 94%, 92%, 95%, 97%, and 93% for CT, and 99%, 97%, 98%, 97%, and 99% for PET. According to median SUVmax in the LNM, true positive lymph nodes showed a significantly higher SUVmax than the true negative (median, 13.6 versus 5.0, p=0.001) and false negative lymph nodes (median, 13.1 vs 6.9; p= 0.026). CONCLUSIONS: For EAC pre-operative staging, CT, PET and EUS N-descriptor show comparable diagnostic performance. Nevertheless, due to the low sensitivity rates particularly for N stations close to primary tumors, none of the commonly used imaging modalities is sufficiently reliable for cStaging.