The prognosis valve of tumor regression grade in the same ypStage patients after neoadjuvant treatment in locally advanced rectal cancer: Post-hoc analysis of a prospective trial

• Published in: Journal of clinical oncology Vol. 38; no. 15_suppl; p. e16129
• Main Authors: Zhang, Jianwei, Cai, Yue, Hu, Huabin, Wu, Zehua, Xie, Xiaoyu, Ling, Jiayu, Deng, Yanhong
• Format: Journal Article
• Language: English
• Published: 20.05.2020
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/JCO.2020.38.15_suppl.e16129

Abstract only e16129 Background: The ypStage after neoadjuvant treatment was an important prognosis factor in locally advanced rectal cancer (LARC). pCR or ypStage 0 showed best prognosis, while ypStage II-III showed poor prognosis and further adjuvant chemotherapy with FOLFOX was recommended. Tumor regression grade (TRG) was another factor to evaluate the response to neoadjuvant treatment. Even in the same ypStage, the TRG could be different. Here, we tried to analyze the prognosis valve of TRG in the same ypStage after neoadjuvant treatment in LARC from a prospective trial (FOWARC study). Methods: Patients with stage II/III rectal cancer were randomly assigned (1:1:1) to five cycles of infusional fluorouracil plus radiotherapy followed by surgery and seven cycles of infusional fluorouracil as adjuvant treatment, the same treatment plus intravenous oxaliplatin 85 mg/m2 on day 1 of each cycle (mFOLFOX6), or four to six cycles of mFOLFOX6 followed by surgery and six to eight cycles of mFOLFOX6. The primary end point was 3-year disease-free survival (DFS). Survival analysis was performed on different ypStage and TRG (WHO classification) group. Results: In total, 495 patients were randomly assigned to different neoadjuvant treatment. 444 patients received surgery with a median follow-up of 45.2 months. The 3-year disease free survival (DFS) in ypStage 0, ypStage I, ypStage II and ypStage III was 95.8%, 89.2%, 71.7% and 55.1%, respectively (P < 0.0001). In TRG 0, 1, 2 and 3, the 3-year DFS was 93.3%, 83.2%, 68.4% and 63.6%, respectively (P < 0.0001). In ypStage I subgroup, TRG was not an independent prognosis factor, the 3-year DFS for TRG 1, 2 and 3 was 90.0%, 90.7% and 76.2%, respectively (P = 0.277). In ypStage II population, the 3-year DFS for TRG 1, 2 and 3 was 78.6%, 70.3% and 64.7%, respectively (P = 0.184). The ypStage III group showed great heterogeneity, the 3-year DFS for TRG 0-3 was 60.0%, 70.0%, 41.8% and 59.5%, respectively (P = 0.067). Conclusions: Both ypStage and TRG was strong prognosis factor for rectal cancer after neoadjuvant treatment. However, TRG was not an independent prognosis factor in the same ypStage after neoadjuvant treatment. Clinical trial information: NCT01211210 .