Terminal (Stage 4) Rectal Cancer: What Is the Expected Survival Period? (2026 Update)

For colorectal cancer, including rectal cancer, even stage 4 (terminal) cases may be treated with curative intent if the metastatic sites can be surgically removed, so survival duration cannot be reduced to a single number. South Korea's overall 5-year relative survival rate for colorectal cancer is 75.6%, but this is only a national statistic and does not predict an individual's prognosis.

Key Takeaways

• South Korea's 5-year relative survival rate for colorectal cancer is 75.6% (National Cancer Registration Statistics 2019–2023, National Cancer Center Korea's Central Cancer Registry). The combined 5-year relative survival rate for all cancers in the same period is 73.7%.
• Even at stage 4 (terminal/advanced stage), if metastatic sites such as the liver or lungs can be surgically removed, treatment combining chemotherapy with metastasis resection may aim for a cure. This means the range of conditions described as "stage 4" is wider for colorectal cancer than for many other cancers.
• When metastatic sites cannot be removed, systemic chemotherapy becomes the main approach, with targeted therapies or immune checkpoint inhibitors added depending on RAS, BRAF, MSI, and HER2 results. Immunotherapy is known to be particularly effective in MSI-High cases.
• Survival rates are population averages and are not numbers that predict an individual outcome. Actual clinical course varies greatly from person to person depending on stage, location and number of metastases, age, overall health, and treatment response.

Does Stage 4 (Terminal) Rectal Cancer Mean Treatment Is No Longer Possible?

• No. Stage 4 in the colorectal cancer TNM staging system means the presence of M (distant metastasis). Even if the cancer has spread to the liver or lungs, whether that metastatic site can be surgically removed is the key factor determining the treatment direction.
• If the metastatic site can be removed, treatment combining chemotherapy with metastasis resection may be pursued with curative intent. Conversely, if it cannot be removed, the goal shifts to tumor control and symptom management, with systemic chemotherapy as the main approach.
• In this case, drug selection depends on biomarker test results such as RAS, BRAF, MSI/MMR, and HER2, and immune checkpoint inhibitors are known to be particularly effective in MSI-High cases.

Does the 75.6% Survival Rate Apply to Terminal-Stage Patients as Well?

• No. The 75.6% figure is the overall 5-year relative survival rate for colorectal cancer across all stages, from early to terminal (National Cancer Registration Statistics 2019–2023), and the number varies significantly when broken down by stage.
• This is a national statistic covering patients across Korea as a whole, not the treatment outcomes of any specific hospital. For reference, the 5-year relative survival rate for colorectal cancer according to the U.S. SEER statistics is 65.4% (2016–2022). The gap between the two countries stems not only from treatment technology but also substantially from differences in early detection rates through national screening programs.
• Therefore, it is difficult to directly apply this overall average figure—which does not reflect an individual's stage, extent of metastasis, or treatment response—as a prediction of one's own expected survival period.

What Is the Process for Terminal-Stage Patients to Decide on Treatment?

• Step 1 – Testing: Colonoscopy and biopsy confirm the cancer, abdominal and chest CT scans check for liver/lung metastases and lymph node involvement, and for rectal cancer, pelvic MRI assesses the degree of bowel wall invasion and the distance to the anal sphincter muscles.
• Step 2 – Biomarker testing: CEA levels are measured in the blood, and biomarkers such as MSI/MMR, RAS, BRAF, and HER2 are tested to provide the basis for drug selection.
• Step 3 – Decision-making: Doctors assess whether the metastatic sites are resectable, taking into account the number and location of metastases and liver function, to decide between curative-intent treatment and control-focused treatment.
• Step 4 – Treatment: If resectable, chemotherapy is combined with metastasis resection (liver resection, radiofrequency ablation, etc.); if not resectable, systemic chemotherapy continues with the addition of targeted therapies or immune checkpoint inhibitors.
• Step 5 – Follow-up: The treatment plan is periodically reassessed based on treatment response.

FAQ — Can Rectal Cancer That Has Spread to the Liver or Lungs Still Be Treated?

Liver resection, radiofrequency ablation, radiation therapy, and chemotherapy are combined depending on the number and location of metastases and liver function. Colorectal cancer is known as a cancer that is actively treated even with metastasis, as long as resection is possible, and the written opinion from the review report will indicate resectability and treatment sequencing.

FAQ — Can Biomarker Test Results From Abroad Be Used As-Is?

In most cases, they can be used as reference material as-is. However, because testing methods and interpretation criteria differ between institutions, biomarkers that are critical for drug selection (RAS, BRAF, MSI, HER2) are sometimes re-confirmed using paraffin blocks. If you prepare the original biopsy and pathology report along with the paraffin block or slides, a re-review can be conducted.

Sources and Notes

• This article was written based on National Cancer Registration Statistics 2019–2023 (National Cancer Center Korea's Central Cancer Registry), SEER 2016–2022 statistics (U.S. National Cancer Institute), and general information at the level of the National Cancer Information Center and NCCN patient guidelines.
• This content is intended to provide general medical information, and actual diagnosis, treatment methods, and outcomes may vary depending on individual conditions. Accurate diagnosis and treatment should always be determined through consultation with medical professionals.