Down-staging depth score to predict outcomes in locally advanced rectal cancer achieving ypI stage after neoadjuvant chemo-radiotherapy versus de novo stage pI cohort: A propensity score-matched analysis

Ning Li; Jing Jin; Jing Yu; Shuai Li; Yuan Tang; Hua Ren; Wenyang Liu; Shulian Wang; Yueping Liu; Yongwen Song; Hui Fang; Zihao Yu; Yexiong Li

doi:10.21147/j.issn.1000-9604.2018.03.09

Down-staging depth score to predict outcomes in locally advanced rectal cancer achieving ypI stage after neoadjuvant chemo-radiotherapy versus de novo stage pI cohort: A propensity score-matched analysis

Chin J Cancer Res. 2018 Jun;30(3):373-381. doi: 10.21147/j.issn.1000-9604.2018.03.09.

Authors

Ning Li¹, Jing Jin¹, Jing Yu¹, Shuai Li¹, Yuan Tang¹, Hua Ren¹, Wenyang Liu¹, Shulian Wang¹, Yueping Liu¹, Yongwen Song¹, Hui Fang¹, Zihao Yu¹, Yexiong Li¹

Affiliation

¹ Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.

PMID: 30046231
PMCID: PMC6037589
DOI: 10.21147/j.issn.1000-9604.2018.03.09

Abstract

Objective: Prognosis of patients with locally advanced rectal cancer (LARC) but achieving ypT1-2N0 stage after neoadjuvant concurrent chemo-radiotherapy (CRT) has been shown to be favorable. This study aims to determine whether the long-term outcome of ypT1-2N0 cases can be comparable to that of pT1-2N0 cohort that received definitive surgery for early disease.

Method: From January 2008 to December 2013, 449 consecutive patients with rectal cancer were treated and their outcome maintained in a database. Patients with LARC underwent total mesorectal excision (TME) surgery at 4-8 weeks after completion of CRT, and those achieving stage ypI were identified as a group. As a comparison, stage pI group pertains to patients whose initially limited disease was not upstaged after TME surgery alone. After propensity score matching (PSM), comparisons of local regional control (LC), distant metastasis-free survival (DMFS), disease-free survival (DFS) and overall survival (OS) were performed using Kaplan-Meier analysis and log-rank test between ypI and pI groups. Down-staging depth score (DDS), a novel method of evaluating CRT response, was used for subset analysis.

Results: Of the 449 patients, 168 matched cases were generated for analysis. Five-year LC, DMFS, DFS and OS for stage pI vs. ypI groups were 96.7% vs. 96.4% (P=0.796), 92.7% vs. 73.6% (P=0.025), 91.2% vs. 73.6% (P=0.080) and 93.1% vs. 72.3% (P=0.040), respectively. In the DDS-favorable subset of the ypI group, LC, DMFS, DFS and OS resulted in no significant differences in comparison with the pI group (P=0.384, 0.368, 0.277 and 0.458, respectively).

Conclusions: LC was comparable in both groups; however, distant metastasis developed more frequently in down-staged LARC than de novo early stage cases, reflecting the need to improve the efficacy of systemic treatment despite excellent pathologic response. DDS can be an indicator to identify a subset of the ypI group whose long-term oncologic outcomes are as good as those of stage pI cohort.

Keywords: Rectal neoplasms; down-staging; neoadjuvant chemo-radiotherapy; propensity score-matched analysis.