Incremental value of endoscopic brush cytology in response assessment after chemo-irradiation for Esophageal cancer.

BACKGROUND: Response assessment after chemo-radiotherapy (CTRT) in locally advanced esophageal cancer is usually performed using a PET-CT scan, an upper GI endoscopy (UGIE) and histological correlation with biopsy or cytology. We aim to study the incremental value of brush cytology in addition to PET-CT for response assessment.

MATERIALS AND METHODS: In this retrospective analysis, 40 patients with Stage II- IV carcinoma esophagus treated with radical intent between June 2015 and August 2019 were included. Patients were treated with either upfront concurrent CTRT or neo-adjuvant chemotherapy followed by CTRT. All patients underwent PET-CT and UGIE for initial staging and response assessment on follow-up. Patients with esophageal stricture (disease related or treatment induced) had brush cytology done during UGIE. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of brush cytology were calculated considering serial clinical follow-up as gold standard.

RESULTS: Twenty-three male (57.5%) and 17 (42.5%) female patients with median age of 57 years (range: 27 - 79 years) were analyzed. Concurrent CTRT was delivered in 52.5%; 75% patients were treated with intensity-modulated radiotherapy (IMRT); median RT dose was 63 Gy (range- 41.4 to 64 Gy). At a median follow-up of 16 months (range 6- 54 months), 20 patients (55.5%) were clinically controlled, 9 (25%) had local recurrence, 5 (13.8%) had loco-regional recurrence and 2 had distant metastasis. Considering clinical follow-up as the gold standard, sensitivity, PPV and NPV of PET-CT combined with brush cytology improved compared to PET-CT alone and was found to be 75%, 90%, 85.7% and 81.8% respectively.

CONCLUSION: We found that brush cytology on endoscopy is a simple tool with high specificity which adds value to the findings of response assessment PET-CT scan and thereby can increase the confidence of the treating oncologist in making clinical decisions.