Colon cancer is one of the most common cancers worldwide, and even after curative (radical) surgery, some patients develop recurrence or distant metastasis. Understanding how tumor stage and lymph node status at the time of diagnosis influence the risk and patterns of recurrence is important for guiding follow-up and treatment strategies. This study retrospectively evaluates patients with stage I-III colon cancer who underwent radical surgery at Chang Gung Memorial Hospital between 2006 and 2018. A total of 7,259 patients are included from the institutional tumor registry. Patients are categorized into four tumor-node (TN) stage groups: * T1-3 without lymph node involvement * T1-3 with lymph node involvement * T4 without lymph node involvement * T4 with lymph node involvement The study aims to examine recurrence patterns (no recurrence, local recurrence, isolated lung metastasis, isolated liver metastasis, or multiple sites) and overall survival. Statistical analyses planned include Kaplan-Meier survival analysis and marginal structural models to compare outcomes across different TN stages and recurrence types. This study is based on retrospective data and was approved by the Institutional Review Board of Chang Gung Memorial Hospital (IRB No: 202500389B0). No new patient enrollment or interventions will be performed, and patient consent was waived due to the retrospective nature of the study.
Colon cancer remains a major cause of cancer-related morbidity and mortality worldwide. Even after curative resection, recurrence occurs in a significant proportion of patients, and survival outcomes vary depending on tumor and nodal status at diagnosis. While the TNM staging system is widely used for prognosis, the specific association between tumor-node (TN) combinations and recurrence patterns, as well as their impact on survival, is not fully established. The objective of this study is to investigate the relationship between TN stage and recurrence patterns in patients with stage I-III colon adenocarcinoma who underwent radical surgery at Chang Gung Memorial Hospital, Taiwan. A retrospective cohort of 7,259 patients who had surgery between 2006 and 2018 is analyzed using data from the institutional tumor registry. Patients are categorized into four groups according to T and N status: T1-3N0, T1-3N+, T4N0, and T4N+. Primary outcomes include recurrence patterns (local recurrence, isolated lung metastasis, isolated liver metastasis, multiple-site metastases, or no recurrence). The secondary outcome is overall survival, assessed both after surgery and after recurrence. Planned statistical analyses include multinomial logistic regression to evaluate recurrence risk by TN stage, Kaplan-Meier survival curves with log-rank tests to compare survival across recurrence types, and marginal structural models with inverse probability weighting to address time-dependent confounders and estimate causal effects of TN stage and recurrence on mortality risk. This retrospective analysis was reviewed and approved by the Institutional Review Board of Chang Gung Memorial Hospital (IRB No: 202500389B0). Patient consent was waived because only de-identified registry data are used.
Study Type
OBSERVATIONAL
Enrollment
7,259
Chang Gung Memorial Hospital, Linkou
Taoyuan, Taoyuan, Taiwan
Recurrence Patterns After Radical Surgery in Stage I-III Colon Cancer
Recurrence classified as no recurrence, local recurrence, isolated lung metastasis, isolated liver metastasis, or multiple-site metastases, based on imaging and clinical follow-up data.
Time frame: From date of radical surgery until the date of first documented recurrence, assessed up to 60 months.
Overall Survival After Radical Surgery in Stage I-III Colon Cancer
Defined as the time from surgery to death from any cause, assessed using hospital records and national death registry data.
Time frame: From date of radical surgery until death from any cause, assessed up to 5 years.
Disease-Free Survival
Time from surgery to first documented recurrence (local or distant) or death from any cause, whichever occurs first.
Time frame: From date of radical surgery until the date of recurrence or death from any cause, whichever comes first, assessed up to 5 years.
Cancer-Specific Survival (CSS)
Time from surgery to death specifically attributable to colon cancer, assessed through clinical records and registry data.
Time frame: From date of radical surgery until death specifically attributable to colon cancer, assessed up to 5 years.
All-Cause Mortality by Recurrence Pattern
Mortality rates stratified by first recurrence type (local, isolated lung, isolated liver, multiple sites).
Time frame: From date of first documented recurrence until death from any cause, assessed up to 5 years.
Prognostic Impact of Tumor-Node Stage
Association between TN stage at diagnosis (T1-3N-, T1-3N+, T4N-, T4N+) and recurrence/metastasis risk, measured by multinomial regression models.
Time frame: From date of diagnosis and radical surgery until the date of first documented recurrence or metastasis, assessed up to 5 years.
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