How does metastatic esophageal cancer affect laboratory (lab) values?

Laboratory Value Changes in Metastatic Esophageal Cancer

Metastatic esophageal cancer causes significant alterations in laboratory values that reflect disease progression, with the liver being the most common site of metastasis, followed by lung, bone, and brain. 1

Common Laboratory Abnormalities

Blood Count and Inflammatory Markers

• Complete blood count (CBC) may reveal iron-deficiency anemia, which should be assessed as part of initial diagnostic workup 2
• Inflammatory markers show significant prognostic value:
  • Elevated neutrophil-to-lymphocyte ratio (NLR >4.748) correlates with poorer prognosis 3
  • Increased derived neutrophil-to-lymphocyte ratio (dNLR >2.214) 3
  • Higher monocyte-to-lymphocyte ratio (MLR >0.309) 3
  • Elevated platelet-to-lymphocyte ratio (PLR >250.505) 3
  • Increased systemic immune-inflammation index (SII >887.895) 3

Liver Function Tests

• Deranged liver function tests are common, especially with hepatic metastases (present in 45-47% of metastatic cases) 4, 1, 5
• Elevated liver enzymes (ALT, AST) and bilirubin may indicate liver involvement 2
• Abnormal liver function tests are predictive of transmural necrosis and poor outcomes 2

Renal Function

• Renal function abnormalities (elevated creatinine, BUN) may develop, particularly in advanced disease 2
• Renal failure is predictive of transmural necrosis and poor outcomes in esophageal cancer 2

Tumor Markers

• Carcinoembryonic antigen (CEA) may be elevated, particularly in adenocarcinoma
• Preoperative CEA ≥5 mg/mL correlates with poorer prognosis 2
• CEA levels >30 ng/mL are associated with significantly reduced median survival (22 months vs. 34.8 months for CEA <30 ng/mL) 2

Metabolic Abnormalities

• Acid-base disturbances may occur, with severe acidosis (low pH, high blood lactate) indicating transmural necrosis 2
• Electrolyte imbalances including:
  • Hypocalcemia (especially with bone metastases) 2
  • Hyponatremia 2
  • Hypokalemia 2
• Metabolic reprogramming occurs, characterized by:
  • Increased glucose utilization and lactate production (enhanced anaerobic glycolysis) 6
  • Elevated glutamic acid levels (enhanced glutaminolysis) 6
  • Altered cholesterol metabolism 6

Laboratory Changes by Metastatic Site

Liver Metastases (Most Common, 45-47%)

• Elevated liver enzymes (AST, ALT)
• Increased alkaline phosphatase
• Elevated bilirubin (direct and indirect)
• Decreased albumin
• Prolonged prothrombin time/INR 4, 1, 5

Lung Metastases (30-52%)

• Potential hypoxemia on arterial blood gas
• Possible respiratory alkalosis 1, 5

Bone Metastases

• Elevated alkaline phosphatase
• Hypercalcemia or hypocalcemia
• Increased parathyroid hormone-related protein in some cases 4, 1

Brain Metastases

• Syndrome of inappropriate antidiuretic hormone secretion (SIADH) may cause hyponatremia 1

Prognostic Implications of Laboratory Abnormalities

• Thrombocytopenia is predictive of transmural necrosis and poor outcomes 2
• Elevated C-reactive protein (CRP) correlates with worse prognosis 2
• Leukocytosis indicates more aggressive disease 2
• Multivariate analysis shows that laboratory markers combined with clinical features (age, tumor location, grade, T classification, ECOG performance status, and number of metastases) significantly affect prognosis 4

Monitoring During Treatment

• Changes in inflammatory markers can reflect response to treatment:
  • Decreases in NLR, dNLR, PLR, and SII are associated with partial response to immunotherapy 3
  • Significant increases in NLR, dNLR, MLR, and SII occur when anti-PD-1 treatment fails 3
• Regular monitoring of these markers can help assess treatment efficacy and disease progression 3