A Pilot Study of Circulating Tumor Cells in Stage IV Non-Small Cell Lung Carcinoma

Purpose Measurement of the number of circulating tumor cells (CTCs) in the bloodstream has been shown to have prognostic significance in treating breast carcinoma. This pilot study was formulated to determine if stage IV non-small cell lung carcinomas similarly shed malignant cells into the circulation and if their presence has prognostic significance. Methods Patients with stage IV non-small cell lung carcinomas were tested once for CTCs in 7.5 ml of their blood prior to receiving any treatments. A proprietary blood collection kit produced by Veridex LLC (Raritan, NJ), which manufactures the instrument that performs the immunomagnetic CELLSEARCH® CTC assay, was used. Tumor measurements were determined in three dimensions by the same radiologist using computerized axial tomography. The three-dimensional sum was used to represent tumor size. Survival from the date of the pretreatment CTC assay was monitored and recorded. Data were analyzed statistically using NCSS8 statistical software (NCSS LLC, Kaysville, UT). Results Of 19 evaluable patients, 10 had no detectable CTCs. There was no relation between intrapulmonary primary tumor size and the number of CTCs, nor between tumor size and survival. Survival was not affected by gender or age at entry into the trial. The mean survival of those with no detectable CTCs was 536 ± 91.1 days versus 239 ± 96.0 days for those with 1 or more detectable CTCs, a statistically significant advantage (P=0.034) favoring those without CTCs. Conclusions Patients with a CTC score of 0 survived significantly longer than those with a CTC score of ≥ 1. Survival was not correlated with gender, age or primary tumor size. Recovery of CTCs potentially provides a noninvasive source of tumor cells for genomic profiling, which may enable development of a custom treatment plan for the individual patient. Further investigations are warranted and needed.