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Pathologic Complete Response of Primary Tumor Following Preoperative Chemoradiotherapy for Locally Advanced Rectal Cancer: Long-term Outcomes and Prognostic Significance of Pathologic Nodal Status (KROG 09-01)

Yeo, Seung-Gu MD*,†; Kim, Dae Yong MD*; Kim, Tae Hyun MD*; Chang, Hee Jin MD*; Oh, Jae Hwan MD*; Park, Won MD; Choi, Doo Ho MD; Nam, Heerim MD; Kim, Jun-Sang MD§; Cho, Moon-June MD§; Kim, Jong Hoon MD; Park, Jin-hong MD; Kang, Min Kyu MD; Koom, Woong Sub MD#; Kim, Jae-Sung MD**; Nam, Taek-Keun MD††; Chie, Eui Kyu MD‡‡; Kim, Jung Soo MD§§; Lee, Kyung-Ja MD••

doi: 10.1097/SLA.0b013e3181f3f1b1
Original Articles: ORIGINAL STUDY

Objective: To investigate long-term outcomes of locally advanced rectal cancer (LARC) patients with postchemoradiotherapy (post-CRT) pathologic complete response of primary tumor (ypT0) and determine prognostic significance of post-CRT pathologic nodal (ypN) status.

Background: LARC patients with post-CRT pathologic complete response were suggested to have favorable long-term outcomes, but prognostic significance of ypN status has never been specifically defined in ypT0 patients.

Methods: The Korean Radiation Oncology Group collected clinical data for 333 LARC patients with ypT0 following preoperative CRT and curative radical resections between 1993 and 2007. Sphincter preservation surgery and abdominoperineal resection were performed in 283 (85.0%) and 50 (15.0%) patients, respectively. Postoperative chemotherapy was given to 285 (85.6%) patients. Survival was estimated by the Kaplan-Meier method, and the Cox proportional hazard model was used in multivariate analyses.

Results: After median follow-up of 43 (range = 14–172) months, 5-year disease-free survival (DFS) was 84.6% and overall survival (OS) was 92.8%. The ypN status was ypT0N0 in 304 (91.3%), ypT0N1 in 22 (6.6%), and ypT0N2 in 7 (2.1%) patients. The ypN status was the most relevant independent prognostic factor for both DFS and OS in ypT0 patients. The 5-year DFS and OS was 88.5% and 94.8% in ypT0N0 patients, and 45.2% and 72.8% in ypT0N+ patients (both, P < 0.001).

Conclusions: LARC patients achieving ypT0N0 after preoperative CRT had favorable long-term outcomes, whereas positive ypN status had a poor prognosis even after total regression of primary tumor.

This study included 333 locally advanced rectal cancer patients with post-chemoradiotherapy pathologic complete response of a primary tumor, and showed that patients achieving post-chemoradiotharpy ypT0N0 had favorable long-term outcomes, while ypT0N+ status, which occurred in 8.7% of ypT0 patients, had a significantly poorer prognosis similar to that without downstaging.

*Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea;

Department of Radiation Oncology, Soonchunhyang University College of Medicine, Cheonan, Korea;

Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea;

§Department of Radiation Oncology, College of Medicine, Cancer Research Institute, Chungnam National University, Daejeon, Korea;

Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea;

Department of Radiation Oncology, Yeungnam University College of Medicine, Daegu, Korea;

#Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea;

**Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea;

††Department of Radiation Oncology, Chonnam National University Medical School, Gwangju, Korea;

‡‡Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea;

§§Department of Radiation Oncology, Chonbuk National University Hospital, Jeonju, Korea;

••Department of Radiation Oncology, School of Medicine, Ewha Womans University, Mokdong Hospital, Seoul, Korea.

Reprints: Dae Yong Kim, MD, Center for Colorectal Cancer, National Cancer Center, 111 Jungbalsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 410-769, Korea. E-mail: radiopiakim@hanmail.net.

This work was supported by a National Cancer Center grant (NCC-0910010).

All of the authors have participated in the design, execution, and analysis of this work and have approved the final version of the manuscript. There is no conflict of interest in connection with this work and the material described is not under consideration for publication elsewhere. All authors have no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements) that might pose a conflict of interest in connection with the submitted article.

Authorship justification: Each of 19 authors met the all 3 conditions of authorship: (1) authors make substantial contributions to conception and design, and/or acquisition of data, and/or analysis and interpretation of data; (2) authors participate in drafting the article or revising it critically for important intellectual content; and (3) authors give final approval of the version to be published.

© 2010 Lippincott Williams & Wilkins, Inc.