Response to Neoadjuvant Chemoradiotherapy as a Predictor of Long-Term Survival in Patients with Locally Advanced Rectosigmoid Junction Cancer: An Analysis Based On SEER Database.

Background: Neoadjuvant chemoradiotherapy is recommended to locally advanced rectal cancer, especially for the lower and middle ones. However, the role of neoadjuvant chemoradiotherapy in rectosigmoid junction cancer remains undetermined. We investigated whether patients with a good response to neoadjuvant chemoradiotherapy will have a relatively better long-term survival compared with those with no response.

Methods: Overall, 1325 patients diagnosed with locally advanced rectosigmoid junction cancer from Surveillance, Epidemiology, and End-Results (SEER) cancer registry database (2004-2014, America) were selected. All of them had received neoadjuvant chemoradiotherapy and were evaluated by Collaborative Stage Data Collection System. We performed Kaplan-Meier univariate analysis and Cox regression multivariate analysis models to estimate the potential prognostic factors of long-term survival outcomes. Response to neoadjuvant chemoradiotherapy and histological type of tumor were the two prognostic factors.

Results: The 5-year OS was 78.1% in responders, and 63.4% in nonresponders. In addition the 5-year DSS was 85.1% in responders, and 72.9% in nonresponders.

Conclusion: Based on SEER database in locally advanced rectosigmoid junction cancer, patients with a good response to neoadjuvant chemoradiotherapy could have a benefit of long-term survival.