🧬 Tumor Marker Summary for Ovarian, Breast, Colorectal & Pancreatic Cancers

1. CA 125 (Cancer Antigen 125)

• 🧠 Organ: Ovaries
• 🎯 Used For:
  • Monitoring epithelial ovarian cancer
  • Evaluating treatment response and detecting recurrence
  • Sometimes used to evaluate pelvic masses
• 📈 High CA125:
  • Ovarian cancer
  • Endometriosis, menstruation, pregnancy
  • Liver disease, peritonitis
• ✅ Fasting: Preferred but not mandatory
• ✅ Normal Range: < 35 U/mL
• ⚠️ Note: Not reliable for screening due to many false positives in benign conditions

2. CA 15-3 (Cancer Antigen 15-3)

• 🧠 Organ: Breast
• 🎯 Used For:
  • Monitoring breast cancer (especially advanced/metastatic)
  • Detecting recurrence post-treatment
• 📈 High CA 15-3:
  • Breast cancer (especially stage III/IV)
  • Lung, liver, ovarian cancers
  • Benign liver disorders, endometriosis
• ✅ Fasting: Recommended
• ✅ Normal Range: < 30 U/mL
• ⚠️ Not useful for early-stage detection or screening

3. CEA (Carcinoembryonic Antigen)

• 🧠 Organ: Primarily colorectal, also lung, pancreatic, breast, and stomach
• 🎯 Used For:
  • Monitoring colorectal cancer progression and recurrence
  • Evaluating treatment success
• 📈 High CEA:
  • Colorectal cancer
  • Lung, pancreatic, gastric, breast cancers
  • Smoking, liver cirrhosis, IBD (mild elevations)
• ✅ Fasting: Yes (especially for baseline)
• ✅ Normal Range:
  • Non-smoker: < 3 ng/mL
  • Smoker: < 5 ng/mL

4. CA 19-9 (Carbohydrate Antigen 19-9)

• 🧠 Organ: Pancreas
• 🎯 Used For:
  • Monitoring pancreatic adenocarcinoma
  • Assessing therapy response or recurrence
• 📈 High CA 19-9:
  • Pancreatic, bile duct, gastric cancers
  • Pancreatitis, obstructive jaundice (non-cancer causes)
• ✅ Fasting: Yes
• ✅ Normal Range: < 37 U/mL
• ⚠️ Not effective as a screening test due to low sensitivity in early-stage pancreatic cancer

📊 Comparison Summary Table

⚠️ Key Points

• Tumor markers are not diagnostic tools alone. They must be interpreted with:
  • Imaging (CT, MRI, PET)
  • Clinical history
  • Biopsy (for definitive diagnosis)
• Mild elevations can occur in benign conditions like inflammation, liver disease, or pregnancy

🧪 Recommended Companion Tests