Abstract 413P
Background
Several risk factors for the recurrence of stage II colon cancer have been proposed; however, they remain unconfirmed. Moreover, whether circulating tumor cells in the peripheral blood are associated with recurrence is also unclear. Here, we identified these risk factors by post-hoc analysis of a prospective clinical trial assessing the efficacy of adjuvant chemotherapy for stage II colon cancer in patients with potential risk factors for recurrence.
Methods
Patients with histologically confirmed stage II colon cancer undergoing R0 resection who met at least one of the following criteria were enrolled: T4, perforation/penetration, poorly differentiated adenocarcinoma, mucinous carcinoma, and <12 dissected lymph nodes. All patients were aged 20–80 years, with ECOG PS scores of 0/1. Patients self-selected surgery alone (group A) or a 6-month oral uracil-tegafur plus leucovorin (UFT/LV; group B) regimen. Patients unable to self-select were randomly assigned to either surgery alone (group C) or UFT/LV (group D). The primary outcome was recurrence. Serum positivity for CEA mRNA ≥24 hours and <2 weeks after surgery was also examined.
Results
Among 1,938 patients from 321 institutions in Japan, 1,915 eligible patients were enrolled. The median follow-up period was 59 months. The number of cases and rate of recurrence in groups A, B, C, and D were 641 (29.8%), 1,239 (22.9%), 18 (33.3%), and 17 (17.6%), respectively. The most common recurrence site after surgery alone was the liver, followed by the lungs and peritoneum. In patients receiving adjuvant chemotherapy, the most common recurrence site was the peritoneum, followed by the liver and lungs. Multivariate analysis after propensity score matching revealed that male sex, T4, <12 dissected lymph nodes, and no adjuvant chemotherapy were significant risk factors for recurrence.
Conclusions
Adjuvant chemotherapy decreased the risk of recurrence after surgery in high-risk stage II colon cancer. Patients with risk factors such as male sex, T4, and <12 dissected lymph nodes should be carefully followed up. Serum CEA mRNA positivity in the peripheral blood after surgery was not associated with recurrence.
Clinical trial identification
JFMC46-1201 trial.
Editorial acknowledgement
Legal entity responsible for the study
Japanese Foundation for Multidisciplinary Treatment of Cancer.
Funding
Taiho Pharmaceutical Co., Ltd.
Disclosure
T. Takahashi: Research grant/Funding (institution): Yakult Honsha; Research grant/Funding (institution): Eli Lilly; Honoraria (self): Takeda Pharmaceutical; Honoraria (self): Sanofi. H. Baba: Research grant/Funding (institution): Taiho Pharmaceutical Co, Ltd.; Honoraria (self): Taiho Pharmaceutical Co, Ltd.. M. Itabashi: Research grant/Funding (institution): Taiho Pharmaceutical Company; Research grant/Funding (institution): Pfizer Japan Inc.; Research grant/Funding (institution): Astellas Pharma Inc.; Research grant/Funding (institution): Chugai Pharmaceutical Company Limited; Research grant/Funding (institution): Takeda Pharmaceutical Company Limited. I. Hyodo: Honoraria (self), Research grant/Funding (institution): Taiho Pharmaceutical Co.,Ltd; Honoraria (self), Research grant/Funding (institution): Chugai Pharmaceutical Co.,Ltd; Honoraria (self), Research grant/Funding (institution): Daiichi Sankyo Co.,Ltd; Honoraria (self), Research grant/Funding (institution): Ono Pharmaceutical Co.,Ltd; Honoraria (self), Research grant/Funding (institution): Bristol-Myers Squibb Co.; Research grant/Funding (institution): Takeda Pharmaceutical Co.,Ltd.; Honoraria (self): Eli Lilly Japan; Honoraria (self): Asahi Kasei Pharma Corp. All other authors have declared no conflicts of interest.