Utility of CEA and CA 15.3 in Breast Cancer

Recommendations for Clinical Context

The American Society of Clinical Oncology explicitly advises against using CEA for screening, diagnosis, and staging due to its low sensitivity and specificity 1, 4
CA 15.3 is not recommended for screening due to its low sensitivity (only 33% in non-metastatic cases) and lack of specificity 3, 1
Both markers lack the necessary sensitivity and specificity to identify early-stage disease, making them unsuitable for routine surveillance after primary treatment 5

The American Society of Clinical Oncology recommends using CEA and CA 15.3 only in patients with confirmed metastatic disease during active therapy, always in combination with imaging and clinical examination 1, 4
CA 15.3 is the primary marker, elevated in 80.8% of metastatic cases, while CEA has a limited complementary role, adding only 2.1% sensitivity when combined with CA 15.3 1, 4
Markers should never be used alone, but always in combination with diagnostic imaging and clinical examination 1, 2

Many clinicians incorrectly order these tests for post-surgical follow-up, which is not supported by evidence and may lead to overdiagnosis without survival benefit 1, 2
Elevated CEA or CA 15.3 requires confirmation with imaging before modifying therapy, as sensitivity is particularly low (50-60% in metastatic cases) 1, 4

Pre-treatment levels of CA 15.3 correlate with advanced stage but are not independent prognostic factors 3, 5

In cases of suspected recurrence with equivocal imaging, PET/CT with 2-[18F]FDG has demonstrated high sensitivity (0.90) and specificity (0.81) when CA 15.3 or CEA are elevated during follow-up 7
The positive predictive value is 0.97 in this specific context, with a median CA 15.3 level of 58.9 U/mL in the presence of metastases vs 35.0 U/mL without metastases (p<0.001) 7