A B S T R A C T PurposeAs treatment options expand for metastatic colorectal cancer (mCRC), a blood marker with a prognostic and predictive role could guide treatment. We tested the hypothesis that circulating tumor cells (CTCs) could predict clinical outcome in patients with mCRC.
Patients and MethodsIn a prospective multicenter study, CTCs were enumerated in the peripheral blood of 430 patients with mCRC at baseline and after starting first-, second-, or third-line therapy. CTCs were measured using an immunomagnetic separation technique.
ResultsPatients were stratified into unfavorable and favorable prognostic groups based on CTC levels of three or more or less than three CTCs/7.5 mL, respectively. Patients with unfavorable compared with favorable baseline CTCs had shorter median progression-free survival (PFS; 4.5 v 7.9 months; P ϭ .0002) and overall survival (OS; 9.4 v 18.5 months; P Ͻ .0001). Differences persisted at 1 to 2, 3 to 5, 6 to 12, and 13 to 20 weeks after therapy. Conversion of baseline unfavorable CTCs to favorable at 3 to 5 weeks was associated with significantly longer PFS and OS compared with patients with unfavorable CTCs at both time points (PFS, 6.2 v 1.6 months; P ϭ .02; OS, 11.0 v 3.7 months; P ϭ .0002). Among nonprogressing patients, favorable compared with unfavorable CTCs within 1 month of imaging was associated with longer survival (18.8 v 7.1 months; P Ͻ .0001). Baseline and follow-up CTC levels remained strong predictors of PFS and OS after adjustment for clinically significant factors.
ConclusionThe number of CTCs before and during treatment is an independent predictor of PFS and OS in patients with metastatic colorectal cancer. CTCs provide prognostic information in addition to that of imaging studies.
BACKGROUND-Cetuximab, a chimeric mouse-human IgG1 monoclonal antibody against the epidermal growth factor receptor, is approved for use in colorectal cancer and squamous-cell carcinoma of the head and neck. A high prevalence of hypersensitivity reactions to cetuximab has been reported in some areas of the United States.
The NCCN Soft Tissue Sarcoma Guidelines include a subsection about treatment recommendations for gastrointestinal stromal tumors (GISTs). The standard of practice rapidly changed after the introduction of effective molecularly targeted therapy (such as imatinib and sunitinib) for GIST. Because of these changes, NCCN organized a multidisciplinary panel composed of experts in the fields of medical oncology, molecular diagnostics, pathology, radiation oncology, and surgery to discuss the optimal approach for the care of patients with GIST at all stages of the disease. The GIST Task Force is composed of NCCN faculty and other key experts from the United States, Europe, and Australia. The Task Force met for the first time in October 2003 and again in December 2006 with the purpose of expanding on the existing NCCN guidelines for gastrointestinal sarcomas and identifying areas of future research to optimize our understanding and treatment of GIST. (JNCCN 2007;5[Suppl 2]:S1–S29)
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