Risk factors for recurrence of esophageal squamous cell carcinoma after pathological complete response to neoadjuvant therapy followed by esophagectomy.

BACKGROUND Prognosis of patients who achieve pathological complete response (pCR) with neoadjuvant therapy (NAT) is better than that of non-pCR patients. Currently, there is no indication for adjuvant immune checkpoint inhibitor therapy after achieving pCR. However, recurrence risk after pCR is reportedly 10%-20% with a poor prognosis. Therefore, we investigated the preoperative risk factors for recurrence in patients with pCR. METHODS We analyzed 56 patients with esophageal squamous cell carcinoma who underwent esophagectomy after neoadjuvant chemoradiotherapy (NACRT) or neoadjuvant chemotherapy (NAC) and were histologically diagnosed with pCR. Preoperative factors were compared between patients with and without recurrence to identify the risk factors. RESULTS Forty-eight patients who achieved pCR received NACRT and 8 received NAC. Ten patients who experienced recurrence (17.9%) had undergone NACRT. The cN2 lesions were more frequent, and pre-NAT blood hemoglobin (Hb) was lower in the recurrence group. In addition, the pre-NAT cross-sectional area (CSA) product of the major and minor diameters of the primary tumor before NAT was significantly higher in recurrent cases (p = 0.041). Multivariate analysis, including the cTNM stage, pre-NAT Hb, and pre-NAT CSA, identified high pre-NAT CSA as the only risk factor for recurrence (odds ratio 11.6, 95% confidence interval 1.3-104.1, and p = 0.028). Cox regression analysis of recurrence-free and overall survival identified only high pre-NAT CSA as a prognostic factor. CONCLUSIONS The recurrence risk is relatively high even in patients who achieve pCR after NAT. High pre-NAT CSA of the primary tumor is a risk factor for recurrence necessitating close surveillance.