PS02.106: THE IMPACT OF HISTOPATHOLOGICAL LYMPH NODE METASTASES AFTER PREOPERATIVE CHEMO-RADIOTHERAPY ON THE PROGNOSIS IN ESOPHAGEAL CANCER PATIENTS

Background Esophageal cancer does not have a good prognosis despite being resectable. A recent randomized controlled trial (the Dutch CROSS study) showed the superiority of preoperative chemo-radiotherapy over surgery alone with regard to the five-year survival. At present, this therapeutic approach is regarded as the standard care in the United States and Europe. However, the prognosis in cases where part of the tumor remains is poor, so additional adjuvant therapy is required. The impact of the histopathological lymph node metastases status after preoperative chemo-radiotherapy on the prognosis is unknown, and is which patients require additional adjuvant therapy to manage lymph node metastases. Methods Esophageal cancer patients with more than five lymph node metastases or lymph node metastases spreading into three fields have a poor prognosis, despite their tumor being resectable. We therefore performed neoadjuvant chemo-radiotherapy in these patients in 1998 (NACRT group). We also performed chemo-radiotherapy for initially unresectable locally advanced esophageal cancer invading adjacent organs and curative surgery for the above-mentioned patients in whom the invasion had disappeared after chemo-radiotherapy (conversion group). The chemo-radiotherapy regimen was the same for both groups and consisted of radiotherapy 40 Gy/20 fr and chemotherapy with 5-FU (500 mg/m2 days 0–4) and CDDP (15 mg/m2 days 1–5). We then examined the impact of the histopathological lymph node metastasis status after preoperative chemo-radiotherapy on the prognosis in our institute. Results Patients with three or more histopathological lymph node metastases had a significantly poorer prognosis than those with fewer metastases in both groups. In the NACRT group, the 5-year survival rate was 35.5% vs. 36.1% (number of lymph node metastases 0 vs. ≥ 1; P = 0.889), 34.0% vs. 36.7% (0–1 vs. ≥ 2; P = 0.678), and 47.1% vs. 0% (0–2 vs. ≥ 3; P = 0.003). In conversion group, it was 40.4% vs. 43.6% (number of lymph node metastases 0 vs. ≥ 1; P = 0.841), 45.6% vs. 33.6% (0–1 vs. ≥ 2; P = 0.106), and 49.5% vs. 20.0% (0–2 vs. ≥ 3; P = 0.025). Conclusion Patients with three or more histopathological lymph node metastases after preoperative chemo-radiotherapy had a significantly poorer prognosis than those with fewer metastases and required additional adjuvant therapy. Disclosure All authors have declared no conflicts of interest.