What are the limitations of serum CA 27-29 testing?

Updated: Jul 11, 2019
  • Author: Nikhil G Thaker, MD; Chief Editor: Eric B Staros, MD  more...
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Breast cancer is one of several conditions that may cause elevated levels of CA 27-29 (Table 1), and not all breast cancers cause an elevation in marker levels. Thus, a rise in CA 27-29 levels could be due to conditions other than breast cancer, making screening and diagnosis difficult.

Early stage breast cancers have a low incidence of CA 27-29, which confers a low sensitivity in this population of patients. Although high levels of CA 27-29 can indicate metastatic disease, evidence is currently insufficient to incorporate CA 27-29 levels into the staging system.

Early recurrence of disease can be predicted by an average of 5-6 months prior to other signs or symptoms. However, the benefit of this post-treatment monitoring is controversial, since no studies have shown that detection of early recurrence leads to more effective therapy and an improvement in patient outcome. The cost-effectiveness of early treatment and its impact on toxicity also remain unknown.

Low sensitivity in early stage breast cancer, low overall specificity, and lack of effective treatment for recurrences are important limitations of the CA 27-29 assay. [15] Prospective, randomized trials will be needed to further clarify the clinical utility and impact on patient outcome of CA 27-29.

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