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).
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.
Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
Seung-Gu
SG
Yeo
Dae Yong
DY
Kim
Tae Hyun
TH
Kim
Hee Jin
HJ
Chang
Jae Hwan
JH
Oh
Won
W
Park
Doo Ho
DH
Choi
Heerim
H
Nam
Jun-Sang
JS
Kim
Moon-June
MJ
Cho
Jong Hoon
JH
Kim
Jin-Hong
JH
Park
Min Kyu
MK
Kang
Woong Sub
WS
Koom
Jae-Sung
JS
Kim
Taek-Keun
TK
Nam
Eui Kyu
EK
Chie
Jung Soo
JS
Kim
Kyung-Ja
KJ
Lee
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011300:Preoperative Care; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D012074:Remission Induction; D016896:Treatment Outcome
D000970:Antineoplastic Agents