Early Systemic Failure After Preoperative Chemoradiotherapy for the Treatment of Patients With Rectal Cancer.

Purpose: Distant metastasis can occur early after neoadjuvant chemoradiotherapy (CRT) in patients with rectal cancer. This study was conducted to evaluate the clinical characteristics of patients who developed early systemic failure.

Methods: The patients who underwent neoadjuvant CRT for a rectal adenocarcinoma between June 2007 and July 2015 were included in this study. Patients who developed distant metastasis within 6 months after CRT were identified. We compared short- and long-term clinicopathologic outcomes of patients in the early failure (EF) group with those of patients in the control group.

Results: Of 107 patients who underwent neoadjuvant CRT for rectal cancer, 7 developed early systemic failure. The lung was the most common metastatic site. In the EF group, preoperative carcinoembryonic antigen was higher (5 mg/mL vs. 2 mg/mL, P = 0.010), and capecitabine as a sensitizer of CRT was used more frequently (28.6% vs. 3%, P = 0.002). Of the 7 patients in the EF group, only 4 underwent a primary tumor resection (57.1%), in contrast to the 100% resection rate in the control group (P < 0.001). In terms of pathologic outcomes, ypN and TNM stages were more advanced in the EF group (P < 0.001 and P = 0.047, respectively), and numbers of positive and retrieved lymph nodes were much higher (P < 0.001 and P = 0.027, respectively).

Conclusion: Although early distant metastasis after CRT for rectal cancer is very rare, patients who developed early metastasis showed a poor nodal response with a low primary tumor resection rate and poor oncologic outcomes.