Chemoresistance profile of circulating tumor cells: Toward a clinical benefit?

摘要

The detection, characterization and count of circulating tumor cells (CTC) in cancer patients, although intriguing and promising, still raises some opened questions. After the pioneer investigation performed by Cristofanilli, showing that the number of CTC before treatment is an independent predictor of progression-free survival and overall survival in patients with metastatic breast cancer, further investigations have demonstrated that CTC have superior and independent prognostic value of tumor burden and better correlate with overall survival than do changes determined by traditional radiology. All these new concepts open the era of the "microscopic" revolution, a definition used by Cristofanilli in 2005. Despite the undoubted prognostic significance of CTC count, oncologists are still wondering on the real significance of CTC, focusing their attention on a crucial point, the clinical benefit.Although several clinical trials have recently demonstrated the correlation between CTC count and prognosis of patients, some questions are still unsolved, such as the nature of these cells and, more important, the therapeutic consequences of their detection and enumeration. Specifically, the question of what to do when CTC levels rise in course of treatment still remains unanswered. The hypothetical solutions could be the switch to a different regimen, other than the completion of the planned course, or the addition of new agents.