Colon Cancer

After histologic confirmation on colonoscopy, obtain a baseline CEA and contrast-enhanced CT of the chest, abdomen, and pelvis. These studies establish a pre-treatment disease burden, identify liver, lung, peritoneal, or nodal metastases, and provide a reference for subsequent treatment response or recurrence assessment. ScienceDirect+1ScienceDirectNon-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR) - ScienceDirectNatureColorectal cancer

Refer patients with obstruction, perforation, uncontrolled bleeding, or impending perforation for urgent surgical assessment rather than delaying management for a complete elective staging sequence. In clinically stable patients, use multidisciplinary review to determine whether imaging suggests resectable localized disease, potentially resectable metastatic disease, or unresectable metastatic disease requiring systemic therapy first. ScienceDirect+1ScienceDirectPrimary colon cancer: ESMO Clinical Practice Guidelines for diagnosis, adjuvant treatment and follow-upESMOESMO Clinical Practice Guideline: Metastatic Colorectal Cancer

Document the preoperative CEA even when imaging suggests localized disease because postoperative interpretation depends on whether the marker was elevated at diagnosis. Colonoscopy also identifies synchronous lesions and permits biopsy, but a lesion that cannot be traversed should not prevent cross-sectional staging or surgical planning. ScienceDirect+1ScienceDirectNon-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR) - ScienceDirectNatureColorectal cancer

For resectable nonmetastatic colon cancer, oncologic colectomy is the central curative intervention. The resection specimen establishes pT category, nodal status, margin status, grade, and other adverse pathologic features that distinguish stage I disease requiring observation from stage II disease requiring individualized risk discussion and stage III disease generally requiring adjuvant chemotherapy. ScienceDirect+1ScienceDirectNon-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR) - ScienceDirectScienceDirectPrimary colon cancer: ESMO Clinical Practice Guidelines for diagnosis, adjuvant treatment and follow-up

Stage II is the principal adjuvant-treatment gray zone. In high-risk stage II disease, discuss adjuvant chemotherapy and offer fluoropyrimidine monotherapy or oxaliplatin-based treatment according to the number and type of poor prognostic features, expected absolute benefit, postoperative recovery, and the risk of oxaliplatin neurotoxicity. ScienceDirectScienceDirectNon-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR) - ScienceDirect

Stage III colon cancer should generally receive an oxaliplatin-containing adjuvant regimen, typically FOLFOX or CAPOX. Treatment duration should be individualized by recurrence risk and neurotoxicity tradeoff; the duration question is especially relevant because cumulative oxaliplatin exposure causes neuropathy. ScienceDirect+2ScienceDirectNon-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR) - ScienceDirectNatureYoung-onset colorectal cancer | Nature Reviews Disease PrimersScienceDirectColon Cancer Survivorship in Patients Who Have Received Adjuvant Chemotherapy

When adjuvant chemotherapy is selected, initiate it once the patient is medically able to receive treatment, ideally no later than 6 to 8 weeks after surgery. Use postoperative functional status, wound healing, renal function, residual neuropathy, and patient goals to decide whether a fluoropyrimidine-only approach is preferable to oxaliplatin exposure. Nature+1NaturectDNA applications and integration in colorectal cancer: an NCI Colon and Rectal–Anal Task Forces whitepaper | Nature Reviews Clinical OncologyScienceDirectNon-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR) - ScienceDirect

For metastatic colon cancer, obtain tumor testing for mismatch-repair deficiency or microsatellite instability, RAS alterations, and BRAF V600E before selecting biologic therapy. Additional actionable markers increasingly include HER2, KRAS G12C, POLE/POLD1, and other molecular alterations that can determine eligibility for biomarker-directed treatment or clinical trials. Wiley+2WileyCirculating Tumor DNA and Precision Biomarkers in Colorectal Cancer: Implications for Diagnosis, Monitoring, and Management of Advanced Disease - Srinivasalu - 2026 - Journal of Gastroenterology and Hepatology - Wiley Online LibraryNatureLate-line options for patients with metastatic colorectal cancer: a review and evidence-based algorithm | Nature Reviews Clinical OncologyESMOESMO Clinical Practice Guideline: Metastatic Colorectal Cancer

dMMR/MSI-H status is a treatment-defining result in metastatic colorectal cancer. It occurs in approximately 3% to 5% of metastatic cases and identifies a population for which immunotherapy is central to systemic-treatment selection; dMMR/MSI-H in an early-stage tumor also should prompt evaluation of whether the biology is sporadic MLH1 silencing or an inherited Lynch syndrome pathway. Wiley+1WileyPrognostic value of Lynch syndrome, BRAFV600E, and RAS mutational status in dMMR/MSI‐H metastatic colorectal cancer in a pooled analysis of Dutch and French cohorts - Zwart - 2023 - Cancer Medicine - Wiley Online LibraryWileyCirculating Tumor DNA and Precision Biomarkers in Colorectal Cancer: Implications for Diagnosis, Monitoring, and Management of Advanced Disease - Srinivasalu - 2026 - Journal of Gastroenterology and Hepatology - Wiley Online Library

Do not use cetuximab or panitumumab in RAS-mutated metastatic disease. Among RAS-wild-type tumors, anti-EGFR outcomes are more favorable for left-sided than right-sided primaries, while BRAF mutation is associated with low anti-EGFR response; integrate primary sidedness and BRAF status rather than treating RAS wild type as a sufficient selection criterion. NatureNatureComprehensive review of targeted therapy for colorectal cancer | Signal Transduction and Targeted Therapy

For unresectable metastatic disease, choose initial therapy according to tumor biology, disease tempo, symptom burden, organ function, prior oxaliplatin exposure, performance status, and whether tumor shrinkage could make metastases resectable. Subsequent-line planning should preserve options for anti-EGFR therapy, biomarker-directed drugs, immunotherapy for dMMR/MSI-H disease, and clinical trials. ESMO+1ESMOESMO Clinical Practice Guideline: Metastatic Colorectal CancerNatureLate-line options for patients with metastatic colorectal cancer: a review and evidence-based algorithm | Nature Reviews Clinical Oncology

After curative-intent therapy, surveillance should be structured around recurrence detection, colonoscopic identification of metachronous neoplasia, and monitoring of late surgical and treatment effects. Major U.S. and international organizations provide survivorship guidance, although specific schedules vary because high-quality trial evidence for individual follow-up components remains limited. ScienceDirect+1ScienceDirectColon Cancer Survivorship in Patients Who Have Received Adjuvant ChemotherapyPubMedAmerican Cancer Society Colorectal Cancer Survivorship Care Guidelines - PMC

Trend CEA only in the context of the baseline value, serial measurements, imaging, symptoms, and examination; an isolated abnormal CEA should prompt confirmation and directed evaluation rather than automatic attribution to recurrence. Use surveillance imaging and colonoscopy according to the treating oncology team's stage-specific protocol, particularly when detection of recurrence could lead to resection or other potentially curative local therapy. ScienceDirect+1ScienceDirectColon Cancer Survivorship in Patients Who Have Received Adjuvant ChemotherapyPubMedAmerican Cancer Society Colorectal Cancer Survivorship Care Guidelines - PMC

ctDNA can identify molecular residual disease, recurrence risk, treatment response, and clonal evolution, but it should not replace conventional pathologic staging, radiographic staging, or standard postoperative surveillance. A positive result indicates higher-risk biology, whereas a negative test does not exclude residual disease because low tumor burden and low input-molecule numbers can limit assay sensitivity. Nature+1NaturectDNA applications and integration in colorectal cancer: an NCI Colon and Rectal–Anal Task Forces whitepaper | Nature Reviews Clinical OncologyWileyCirculating Tumor DNA and Precision Biomarkers in Colorectal Cancer: Implications for Diagnosis, Monitoring, and Management of Advanced Disease - Srinivasalu - 2026 - Journal of Gastroenterology and Hepatology - Wiley Online Library

During and after oxaliplatin exposure, assess sensory neuropathy at each treatment review and document functional consequences such as impaired gait, dexterity, or cold-triggered symptoms. Survivorship assessments should also address fatigue, anxiety, depression, bowel dysfunction, sexual dysfunction, and treatment-related pain rather than limiting follow-up to recurrence testing. ScienceDirect+1ScienceDirectColon Cancer Survivorship in Patients Who Have Received Adjuvant ChemotherapyPubMedAmerican Cancer Society Colorectal Cancer Survivorship Care Guidelines - PMC