Test reports:
The results of the CELLSEARCH®CTC Test are reported as a specific CTC level, compared to predetermined cutoff thresholds which indicate a favorable versus unfavorable prognosis for metastatic breast (mBC), prostate (mPC), and colorectal (mCRC) cancers. Cutoff levels were determined via a comprehensive analysis of clinical studies to correlate disease progression and the lowest number of CTCs within a preset range across multiple test subjects. Table 1 lists favorable versus unfavorable tumor cell cutoff levels for mBC, mPC, and mCRC.
Table 1. Tumor Cell Cutoff Levels for Metastatic Cancers (Breast, Prostate, Colorectal). | mBC | mPC | mCRC |
Favorable | 0-4 CTCs | 0-4 CTC’s | 0-2 CTCs |
Unfavorable | ≥ 5 CTCs | ≥ 5 CTCs | ≥ 3 CTCs |
Test result interpretation and clinical usage:
For mBC and mPC, CTC levels of 5 or more CTCs are considered unfavorable, whereas, for mCRC, CTC levels of 3 or more are considered unfavorable. The CELLSEARCH® CTC Test can be ordered at any time during the disease course to assess prognosis and guide therapy. The test is clinically useful for making an early assessment of a patient’s prognosis and for detecting changes in the patient’s prognosis at any given time.
