Detection of cancer cells and tumor margins during colorectal cancer surgery by intraoperative flow cytometry

Flow Cytometry is an analytical technique for the precise quantification of cellular phenotype. Intraoperative Flow Cytometry (iFC) utilizes flow cytometry for DNA content/ploidy and cell cycle distribution analysis during surgery for cancer cell characterization and evaluation of tumor margins. Various types of cancers, including intracranial, head and neck, breast and liver malignancies have been evaluated with iFC. In the current study we present an intraoperative Flow Cytometry protocol for colorectal cancer cell detection and potential resection margin evaluation.This study includes 106 colorectal cancer patients in which samples from cancer and normal colon epithelium were prospectively collected intraoperatively and comparatively assessed with iFC. Patients' demographics, tumor data and cytometry parameters were assessed.We have demonstrated that a cut-off value of 10.5% for tumor-index (fraction of cells in S and G2/M cell cycle phases) predicts with ∼91% accuracy (82.2% sensitivity and 99.9% specificity) the presence of cancer cells. Evaluation of tumor margins by iFC in the subpopulation of rectal cancer patients with or without neoadjuvant therapy, revealed an accuracy of 79% and 88%, respectively.Our data support that regarding colorectal cancer, iFC is a useful adjunct method for tumor cell identification and probably margin evaluation, which could be utilized in rectal cancer treatment in the era of organ sparing procedures.