Correlation between progression free survival and response rate in patients with metastatic colorectal carcinoma

All endpoint measures currently used to evaluate chemotherapeutic treatment benefit in clinical trials of patients with metastatic colorectal carcinoma (MCRC) have disadvantages. Overall survival (OS) is the most objective parameter but is flawed as an efficacy criterion, partly because potentially active second‐line treatments are not controlled in many Phase III studies, and measured OS may be influenced (positively or negatively) to an unknown degree by second‐line therapy. Measuring progression free survival (PFS) may be a means of isolating the real impact of first‐line regimens.