PET-CT and Circulating Tumor Cells in Colorectal Cancer

Identifying an Early Indicator of Drug Efficacy in Patients With Advanced Colorectal Cancer - a Prospective Evaluation of Circulating Tumor Cells, Positron-emission Tomography Scan and RECIST Criteria

The purpose of this study is to identify an early indicator of drug efficacy in patients with advanced colorectal cancer - a prospective evaluation of circulating tumor cells, positron-emission tomography scan and RECIST criteria.

1. To determine if measuring both tumor metabolic response (via FDG-PET scan) & circulating tumor cells (CirTC) at 4 weeks after starting treatment, is a better predictor of clinical outcome than measuring either modality alone in patients with metastatic colorectal cancer (CRC) who are undergoing first-line oxaliplatin-based chemotherapy.
2. To determine if a new method of assessing drug response (measuring tumor metabolic response via FDG-PET & CirTC at 4 weeks after starting treatment) better predicts clinical outcome than the conventional method (measuring radiological changes in tumor dimensions at 10 weeks after starting treatment via the 'Response Evaluation Criteria in Solid Tumors' - RECIST).

Inclusion Criteria:

• Metastatic colorectal cancer patients not received prior drug treatment for metastatic CRC
• Age >= 18 years
• (ECOG) performance status of 0-2
• Measurable tumor sites by RECIST criteria
• Adequate bone marrow, renal & hepatic functions

Exclusion Criteria:

• Patients with diabetes mellitus
• presence of hyperglycemia
• Pregnant or lactating patients