Cancer Antigen (CA) 27.29

Serum

1 mL

0.3 mL (Note: This volume does not allow for repeat testing.)

Red-top tube or gel-barrier tube

Manage patients with metastatic carcinoma of the breast

For the quantitative determination of CA 27.29 antigen in serum of patients previously treated for stage II or stage III breast cancer. Serial testing for CA 27.29 antigen in patients who are clinically free of disease should be used in conjunction with other clinical methods for the early detection of recurrence.

Immunochemiluminometric assay (ICMA)

0−38.6 units/mL

CA 27.29 is a highly polymorphic glycoprotein belonging to the mucin family and is the product of the muc-1 gene. It is most useful using serial measurements to monitor both the course of disease and response to therapy because the direct correlation of changing levels of CA 27.29 with clinical status. In patients with known metastases, a reduction in levels of this marker indicates a good response to treatment while increasing levels indicate resistance to therapy and progressive disease and justify further clinical evaluation and regular monitoring. It has also recently been shown that an elevation of CA 27.29 levels above the upper limit of normal in patients with no clinical evidence of disease is an early indicator of recurrence. An elevated serum CA 27.29 level in patients in remission of stage II or III breast cancer provided a positive predictive value of 83.3% for recurrent disease, with an average lead time of 5.3 months before recurrence was clinically established.