FDG-PET/CT lymph node staging after neoadjuvant chemotherapy in patients with adenocarcinoma of the esophageal–gastric junction

Abstract

ObjectivesThe aim of the analysis was to assess the accuracy of various FDG-PET/CT parameters in staging lymph nodes after neoadjuvant chemotherapy.MethodsIn this prospective study, 74 patients with adenocarcinoma of the esophageal–gastric junction were examined by FDG-PET/CT in the course of their neoadjuvant chemotherapy given before surgical treatment. Data from the final FDG-PET/CT examinations were compared with the histology from the surgical specimens (gold standard). The accuracy was calculated for four FDG-PET/CT parameters: (1) hypermetabolic nodes, (2) large nodes, (3) large-and-medium large nodes, and (4) hypermetabolic or large nodes.ResultsIn 74 patients, a total of 1540 lymph nodes were obtained by surgery, and these were grouped into 287 regions according to topographic origin. Five hundred and two nodes were imaged by FDG-PET/CT and were grouped into these same regions for comparison. In the analysis, (1) hypermetabolic nodes, (2) large nodes, (3) large-and-medium large nodes, and (4) hypermetabolic or large nodes identified metastases in particular regions with sensitivities of 11.6%, 2.9%, 21.7%, and 13.0%, respectively; specificity was 98.6%, 94.5%, 74.8%, and 93.6%, respectively. The best accuracy of 77.7% reached the parameter of hypermetabolic nodes. Accuracy decreased to 62.0% when also smaller nodes (medium-large) were taken for the parameter of metastases.ConclusionsFDG-PET/CT proved low sensitivity and high specificity. Low sensitivity was based on low detection rate (32.6%) when compared nodes imaged by FDG-PET/CT to nodes found by surgery, and in inability to detect micrometastases. Sensitivity increased when also medium-large LNs were taken for positive, but specificity and accuracy decreased.

Significance of baseline FDG-PET/CT scan as a method of staging regional lymph nodes in patients with operable distal oesophageal or gastroesophageal junction adenocarcinoma

“…Moreover, CRT followed by surgery was shown to be as equally effective as definitive CRT in patients with good PET response, while those with poor PET response had better outcome when surgery follows CRT [12]. In contrast, recent studies showed that FDG uptake characteristics of the primary tumour post neoadjuvant CRT [26,27] and the RLN post neoadjuvant chemotherapy [28] were not able to predict the postoperative histopathological tumour results. A considerable weakness of these studies is that many of them [12,14,[18][19][20][21][22][23][24] included patients with mixed characteristics, i.e., both squamous and adenocarcinoma histology and different treatments, making difficult to draw clinically meaningful conclusions.…”

Predicting lymph node metastases with endoscopic resection in cT2N0M0 oesophageal cancer: A systematic review and meta‐analysis

“…Despite increased experience with endoscopic ultrasound (EUS) and positron emission tomography‐CT, in the era of neoadjuvant therapy, the staging accuracy at this tumour stage is not yet satisfactory 42 . One of the great challenges of current imaging modalities is to detect lymph node micrometastasis 43 . In cT2N0M0 patients treated with neoadjuvant chemoradiotherapy, the observed rate of LNM in the surgical resection specimen also remains remarkably high, ranging from 20–50% 18 , 41 , 44 .…”

Hypofractionated Radiotherapy in Combination With Chemotherapy Improves Outcome of Patients With Esophageal Carcinoma Tracheoesophageal Groove Lymph Node Metastasis

“…However, TGLN metastasis after surgery is the major cause of treatment failure of EC, with an incidence of 12–80% ( 2 – 5 ), especially the right lymph node metastasis ( 16 , 17 ). The diagnosis of TGLN metastasis is mainly relied on CT and PET-CT scans ( 6 , 18 – 21 ), where there is a presence of a short diameter ≥0.5 cm and/or high uptake of 18F-PDG ( 22 ). In clinical practice, lymph node metastasis may induce injury of laryngeal nerve, which results in hoarseness and bucking and a poor prognosis.…”