Tumor Necrosis As Prognostic Values In Neoadjuvant Chemoradiotherapy And Laparoscopic Surgery For Locally Advanced Rectal Cancer.

722 Background: Association between treatment response on the basis of pathologic stage evaluated after radical tumor resection and patient prognosis was well established. The object of this study is that tumor necrosis factor after CRT is also important as treatment response. Methods: A total of 243 patients with locally advanced rectal cancer that underwent neoadjuvant CRT was included. Three treatment response groups were classified by their pathologic stage results: complete treatment response (CTR), intermediate treatment response (ITR), and poor treatment response (PTR). Three tissue necrosis groups were classified by tissue pathologic results: complete necrosis response (CNR), intermediate necrosis response (INR), and poor necrosis response (PNR). Results: Overall survival (OS) and recurrence free survival (RFS) rate at 3 years were 74.5% and 61.3%, respectively. The 3-year OS rates of the CTR, ITR, and PTR were 83.7%, 75.9%, and 69.7%, respectively (p<0.001); the 3-year RFS rates were 76.7%, 69.0%, and 52.1%, respectively (p<0.001). The 3-year OS rates of the CNR, INR, and PNR were 83.7%, 80.6%, and 61.8%, respectively (p<0.001); the 3-year RFS rates were 76.7%, 68.9%, and 44.3%, respectively (p<0.001). When compared to CTR / CNR, PTR / PNR was strongly related to an increased risk of recurrence (hazard ratio, 5.53; 95% CI, 2.01 to 15.23 / 6.37; 95% CI, 2.29 to 17.74) respectively in the univariate Cox regression. Therefore in the two models using multivariate Cox regression, both PTR and PNR were strongly associated to RFS and OS compared with CTR and CNR. Conclusions: The tissue response factor to neoadjuvant CRT is one surrogate marker for recurrence and oncologic outcomes and almost as important as the treatment response factor in rectal cancer patients treated with neo-adjuvant CRT.