Jeri Matera

Tumor Cells Circulate in the Peripheral Blood of All Major Carcinomas but not in Healthy Subjects or Patients With Nonmalignant Diseases

Purpose: The purpose of this study was to determine the accuracy, precision, and linearity of the CellSearch system and evaluate the number of circulating tumor cells (CTCs) per 7.5 mL of blood in healthy subjects, patients with nonmalignant diseases, and patients with a variety of metastatic carcinomas. Experimental Design: The CellSearch system was used to enumerate CTCs in 7.5 mL of blood. Blood samples spiked with cells from tumor cell lines were used to establish analytical accuracy, reproducibility, and linearity. Prevalence of CTCs was determined in blood from 199 patients with nonmalignant diseases, 964 patients with metastatic carcinomas, and 145 healthy donors. Results: Enumeration of spiked tumor cells was linear over the range of 5 to 1,142 cells, with an average recovery of ≥85% at each spike level. Only 1 of the 344 (0.3%) healthy and nonmalignant disease subjects had ≥2 CTCs per 7.5 mL of blood. In 2,183 blood samples from 964 metastatic carcinoma patients, CTCs ranged from 0 to 23,618 CTCs per 7.5 mL (mean, 60 ± 693 CTCs per 7.5 mL), and 36% (781 of 2,183) of the specimens had ≥2 CTCs. Detection of ≥2 CTCs occurred at the following rates: 57% (107 of 188) of prostate cancers, 37% (489 of 1,316) of breast cancers, 37% (20 of 53) of ovarian cancers, 30% (99 of 333) of colorectal cancers, 20% (34 of 168) of lung cancers, and 26% (32 of 125) of other cancers. Conclusions: The CellSearch system can be standardized across multiple laboratories and may be used to determine the clinical utility of CTCs. CTCs are extremely rare in healthy subjects and patients with nonmalignant diseases but present in various metastatic carcinomas with a wide range of frequencies.

Circulating Tumor Cells: A Novel Prognostic Factor for Newly Diagnosed Metastatic Breast Cancer

PURPOSE Metastatic breast cancer (MBC) is incurable; its treatment is palliative. We investigated whether the presence of circulating tumor cells (CTCs) predicts treatment efficacy, progression-free survival (PFS), and overall survival (OS) in patients with newly diagnosed MBC who were about to start first-line therapy. PATIENTS AND METHODS One hundred seventy-seven patients with measurable MBC were enrolled onto a prospective study. Eighty-three of the 177 patients were entering first-line treatment, and these patients are the focus of this analysis. CTCs from 7.5 mL of whole blood drawn before treatment initiation (baseline) and monthly thereafter for up to 6 months were isolated and enumerated using immunomagnetics. RESULTS The mean (+/- standard deviation) follow-up time was 11.1 +/- 4.4 months (median, 12.2 months). Forty-three patients (52%) had > or = five CTCs at baseline. The median PFS was 7.2 months (95% CI, 4.9 to 9.4 months), and the median OS was more than 18 months. Patients with > or = five CTCs at baseline and at first follow-up (4 weeks) had a worse prognosis than patients with less than five CTCs (baseline: median PFS, 4.9 v 9.5 months, respectively; log-rank, P = .0014; median OS, 14.2 v > 18 months, respectively; log-rank, P = .0048; first follow-up: median PFS, 2.1 v 8.9 months, respectively; log-rank, P = .0070; median OS, 11.1 v > 18 months, respectively; log-rank, P = .0029). CTCs before and after the initiation of therapy were strong, independent prognostic factors. CONCLUSION Detection of CTCs before initiation of first-line therapy in patients with MBC is highly predictive of PFS and OS. This technology can aid in appropriate patient stratification and design of tailored treatments.

Circulating Tumor Cells versus Imaging—Predicting Overall Survival in Metastatic Breast Cancer

Purpose: The presence of ≥5 circulating tumor cells (CTC) in 7.5 mL blood from patients with measurable metastatic breast cancer before and/or after initiation of therapy is associated with shorter progression-free and overall survival. In this report, we compared the use of CTCs to radiology for prediction of overall survival. Experimental Design: One hundred thirty-eight metastatic breast cancer patients had imaging studies done before and a median of 10 weeks after the initiation of therapy. All scans were centrally reviewed by two independent radiologists using WHO criteria to determine radiologic response. CTC counts were determined ∼4 weeks after initiation of therapy. Specimens were analyzed at one of seven laboratories and reviewed by a central laboratory. Results: Interreader variability for radiologic responses and CTC counts were 15.2% and 0.7%, respectively. The median overall survival of 13 (9%) patients with radiologic nonprogression and ≥5 CTCs was significantly shorter than that of the 83 (60%) patients with radiologic nonprogression and <5 CTCs (15.3 versus 26.9 months; P = 0.0389). The median overall survival of the 20 (14%) patients with radiologic progression and <5 CTCs was significantly longer than the 22 (16%) patients with ≥5 CTCs that showed progression by radiology (19.9 versus 6.4 months; P = 0.0039). Conclusions: Assessment of CTCs is an earlier, more reproducible indication of disease status than current imaging methods. CTCs may be a superior surrogate end point, as they are highly reproducible and correlate better with overall survival than do changes determined by traditional radiology.

Tumor cells circulate in the peripheral blood of all major carcinomas but not in healthy subjects or patients with non-malignant diseases

9552 Background: The number of circulating tumor cells (CTC) in carcinoma patients may provide diagnostic and prognostic information to guide selection and monitor efficacy of therapies. This requires a standardized assay that is accurate and reproducible. Previous studies have demonstrated that CTC can be detected in peripheral blood of cancer patients, but a systematic survey of the prevalence of CTC in healthy subjects, patients with non-malignant diseases and a wide range of carcinomas is needed to establish a foundation for clinical implementation of this technology. METHODS We developed the CellSearch assay to accurately and reproducibly enumerate CTC in 7.5 ml of blood. The assay is based on immunomagnetic enrichment and fluorescent labeling of CTC followed by enumeration on a four color semi-automated fluorescence microscope. Blood from 145 healthy women, 199 women with non-malignant diseases and 1082 patients with a variety of metastatic carcinomas was tested for the presence of CTC. RESULTS Blood samples spiked with tumor cells were used to establish accuracy, reproducibility and linearity of the test. Recovery of spiked cells was ≥ 85% with a CV of 9.4% at a spike of 258 cells and 15.8% at a spike of 47 cells. The assay was linear over the tested range of 4 -1000 cells (r2=0.99). CTC in 344 healthy and non-malignant subjects were extremely rare with only one sample with > 1 cell/7.5 mL. In metastatic carcinoma patients CTC ranged from 0 to 3677 /7.5 mL (mean 32 ± 218). In 36% of the 1082 samples 2 or more CTC were present in 7.5 ml of blood. In 181 prostate cancer patients ≥2 CTC were detected in 57%, in 331 breast cancer patients 37%, in 47 ovarian cancers 36%, in 259 colorectal cancers 30%, and in 149 lung cancer patients 22%. CONCLUSIONS The CellSearch assay is a reliable highly sensitive assay that can be used to explore the clinical utility of CTC in carcinomas. CTC are present in various metastatic carcinomas with a wide range of frequencies. [Table: see text].