Pathology and Laboratory Medicine
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Visual summary · Pathology and Laboratory Medicine

Circulating Tumor Cells: Beyond Isolation and Detection

Michelle J. McNamara

The question

How can circulating tumor cells (CTCs) be used beyond their current focus on prognostic significance?

  • CTCs can be explored for determining if a patient is a candidate for treatment or determining treatment efficacy.
  • They may also be evaluated for resistance to therapy, prediction of metastatic sites, or early prediction of metastases.

What was done

≥85%sensitivity of CELLSEARCH for EpCAM-positive CTCs
70%malignancy diagnosis rate for effusion cytology
8-11 µmleukocyte diameter range
  • Current methodologies to isolate CTCs include physical, immunological, and molecular techniques.
  • Physical techniques rely on size, deformability, density gradient centrifugation, and cell dielectric properties.
  • Immunoaffinity methods use positive or negative enrichment with antibodies to sort CTCs.
  • Full CTC evaluation incorporates histological, immunohistochemical, and molecular characterization.

Key findings

Finding 1 of 4
66%
highest CTC detection rate by CELLSEARCH in rectal cancer among tested metastatic tumor types

In a study of metastatic tumor types, CELLSEARCH detected CTCs in 66% of rectal cancer, 64% of colon cancer, 60% of ovarian cancer, 33% of gastric cancer, and 20% of prostate cancer.

CELLSEARCH detection rate by metastatic tumor type
  • Rectal cancer66%
  • Colon cancer64%
  • Ovarian cancer60%
  • Gastric cancer33%
  • Prostate cancer20%
Finding 2 of 4
70%
effusion cytology malignancy diagnosis rate

Cytology of pleural effusions and ascitic fluid is able to diagnose malignancy in approximately 70% of cases.

Finding 3 of 4
30%
lung cancer patients able to undergo resection

Less than 30% of lung cancer patients are able to undergo resection, with many cases diagnosed by cytology alone.

Finding 4 of 4
75%
lowest specificity of diagnostic molecular profiling

Diagnostic molecular profiling on tumor cells can have specificity as low as 75% due to genetic heterogeneity or genetic evolution.

Why it matters

  • Morphological evaluation of CTCs enables primary diagnosis in cancer of unknown primary (CUP) or early diagnostic scenarios.
  • Combining histological, immunohistochemical, and molecular characterization gives clinicians comprehensive information for personalized cancer care.

How to cite

Michelle J. McNamara. Circulating Tumor Cells: Beyond Isolation and Detection. Pathology and Laboratory Medicine. 2019;2(1):9-17. https://doi.org/10.17140/plmoj-2-108

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