Background
National population-level evidence on survival outcomes and treatment patterns of colon and rectal cancer in China is essential to address critical knowledge gaps for evidence-based cancer policy.
 
Objectives
We aimed to provide the most up-to-date and comprehensive estimates of colon and rectal cancer survival in China, overall and stratified by age and stage at diagnosis. We further examined patterns of surgery and chemotherapy among colorectal cancer patients by subsite, age, and stage at diagnosis, and assessed their associations with prognosis.
 
Methods
We analyzed colorectal cancer survival data from 281 population-based cancer registries covering 32 provincial-level regions in China. A total of 663,716 patients diagnosed with first primary colorectal cancer (ICD-10 codes C18–C20) between 2008 and 2019 were included and followed up until the end of 2021. Additionally, high-resolution cohort data for 7,390 patients with detailed information on stage at diagnosis and treatment modalities were collected from 23 hospitals across 12 provinces, representing regions with varying socioeconomic status. Multivariable logistic regression models were used to evaluate differences in stage distribution and treatment patterns by cancer subsite, and multivariable Cox proportional hazards models were applied to assess associations with overall survival.
 
Results
During 2019–2021, the age-standardized 5-year relative survival was 56.0% for colon cancer and 55.4% for rectal cancer. By colon subsite, 5-year relative survival was 62.9% for distal colon cancer and 60.4% for proximal colon cancer. By age at diagnosis, early-onset colorectal cancer (<50 years) was associated with better survival than cancers diagnosed at older ages (≥50 years); however, patients aged <35 years experienced poorer survival than those aged 35–49 years. Trend analyses showed that 5-year relative survival for rectal cancer increased significantly, whereas no significant improvement was observed for proximal or distal colon cancer. Stage distribution varied markedly by subsite, with the proportion of stage I disease decreasing from rectal cancer (19.9%) to distal colon cancer (12.4%) and proximal colon cancer (8.4%). Among colon cancer patients, surgery rates declined from stages I–II (97%) to stage IV (56.0%), while chemotherapy use increased from stage I (22.1%) to stage IV (73.5%). Similar patterns were observed for rectal cancer, with surgery rates decreasing from stage I (95.9%) to stage IV (53.1%), and chemotherapy rates increasing from stage I (19.1%) to stage IV (75.9%). Surgery, chemotherapy, and stage at diagnosis were independent prognostic factors for both colon and rectal cancer survival.
 
Conclusions / Implications
Our findings identify systemic inequities in early detection and therapeutic access for colorectal cancer in China. This evidence supports policy actions to strengthen risk-stratified colorectal cancer screening, standardize treatment pathways across cancer subsites, and tailor interventions for very young (<35 years), older (>65 years), and advanced-stage patients. These results provide a robust evidence base to optimize health-care resource allocation and advance equitable, data-driven colorectal cancer control strategies in China.