Clinical utility of postchemoradiation endoscopic brush cytology and biopsy in predicting residual esophageal adenocarcinoma

Background: Esophageal adenocarcinoma generally carries a poor prognosis. Treatment with combination chemoradiation (CRT) followed by esophagectomy is becoming common. A pathologic complete response is uncommon but predicts improved survival. Identifying the subset of patients with residual carcinoma has potential management implications. Post-CRT endoscopic brush cytology and biopsy may detect residual tumor; however, the accuracy and clinical value of these methods remain unclear.

Methods: Sixty-seven patients with esophageal adenocarcinoma who underwent preoperative CRT and post-CRT endoscopic brush cytology and biopsy followed by esophagectomy were identified. By using esophagectomy histology as the gold standard, the performance of cytology and biopsy was evaluated in diagnosing residual carcinoma. Two pathologists independently reviewed all false-negative and false-positive cases and resolved disagreements by consensus.

Results: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of cytology for diagnosing residual carcinoma were 26%, 95%, 92%, 35%, and 45%, respectively. For biopsy, these rates were 13%, 90%, 75%, 31%, and 36%, respectively. Sampling error accounted for false-negative diagnoses in approximately 66% of cytology analyses and 98% of biopsy analyses. Approximately 33% of false-negative cytology analyses and 1 false-negative biopsy analysis were caused by the under-recognition of tumor cells. Major diagnostic pitfalls included obscuring acute inflammation, necrosis, tumor cells that mimicked benign cells with radiation/reactive atypia, and the under recognition of mucin-containing adenocarcinoma cells.

Conclusions: Brush cytology and biopsy were specific but not sensitive methods for predicting residual cancer after CRT. However, cytology was superior. The current results indicated that brush cytology can be used alone to diagnose residual esophageal carcinoma, and awareness of specific diagnostic pitfalls will help pathologists improve its accuracy.