Is CA (Cancer Antigen) 125 elevated in patients with lung adenocarcinoma?

CA-125 Elevation in Lung Adenocarcinoma

Yes, CA-125 can be elevated in patients with lung adenocarcinoma, with studies showing elevation in approximately 30-44% of non-small cell lung cancer patients, particularly those with advanced disease (stages 3-4). 1, 2, 3

Evidence for CA-125 Elevation in Lung Cancer

Prevalence and Clinical Significance

• CA-125 is elevated in approximately 30-44% of patients with lung adenocarcinoma 1, 2
• Elevation is more common in advanced disease (stages 3-4) 3
• Higher levels correlate with:
  • Larger tumor size 2
  • More advanced disease stage 1
  • Presence of pleural effusions or ascites 3
  • Poorer prognosis and shorter survival time 3

Diagnostic Value

• At a cut-off value of 15 U/ml, CA-125 has shown:
  • Sensitivity of 44%
  • Specificity of 94-100%
  • Positive predictive value of 94-100% 1
• CA-125 can serve as a prognostic indicator for resectability and survival in lung cancer patients 1

Important Clinical Considerations

Not Specific to Ovarian Cancer

While CA-125 is traditionally associated with ovarian cancer, guidelines clearly acknowledge that it can be elevated in other malignancies, including lung cancer 4. The ESMO guidelines specifically note that "raised CA-125 levels may be found in non-gynaecological malignancies (e.g. breast, lung, colon and pancreatic cancer)" 4.

Monitoring Treatment Response

• CA-125 levels can decrease in response to effective therapy in lung cancer patients 2
• Changes in CA-125 levels may help monitor treatment response in non-small cell lung cancer 2

Limitations and Caveats

• CA-125 is not specific to lung adenocarcinoma and can be elevated in:
  • Other lung cancer subtypes (including squamous cell and small cell) 3, 5
  • Other malignancies (ovarian, breast, pancreatic, etc.) 4, 6
  • Some benign conditions (endometriosis, pelvic inflammatory disease) 4
• CA-125 should not be used alone for diagnosis but can be valuable when combined with other markers like CEA 6, 2
• Sensitivity is limited, especially in early-stage disease 1

Clinical Application

When evaluating a patient with suspected or confirmed lung adenocarcinoma:

1. Consider measuring CA-125 along with other tumor markers (particularly CEA)
2. Interpret elevated CA-125 in the context of the clinical presentation and imaging findings
3. Use CA-125 as an adjunctive marker for:
   • Assessing disease extent
   • Monitoring treatment response
   • Evaluating prognosis

CA-125 elevation in lung adenocarcinoma represents tumor production of this marker and may indicate more advanced or aggressive disease, particularly when levels are significantly elevated.