Effect of platelet inhibition on the risk of development of metastatic disease in colorectal cancer.

Abstract

470 Background: Platelet inhibition has been shown to decrease the risk of metastatic disease in numerous animal models. The use of aspirin to decrease the risk of colorectal cancer (CRC) has been documented in several large studies. However, to date, no studies of whether the use of aspirin or other platelet inhibiting agent (PIA) will reduce the risk of recurrence in patients who develop CRC have been performed. Methods: In this study, we reviewed the charts of all patients treated at the University of Medicine and Dentistry of New Jersey at Newark for stage II or III colon or rectal cancer. Data extracted included use of PIA, stage, treatment, recurrence, time of last contact, and patient characteristics. Patients were defined as having taken a PIA if any evidence of use could be documented. Statistical significance of differences observed was determined using a Fisher's exact test. Results: 111 charts were initially identified. Use of PIA could not be determined for 6, six had metastatic disease at presentation, and one was stage I, leaving 98 patients for analysis. Of these, 35 had evidence of having used PIA, including 20 patients who were taking aspirin. Forty patients without history of use of a PIA had no metastatic disease, compared to 23 patients who developed metastatic disease. For patients taking PIA, 6 developed metastatic disease (Table). Conclusions: Our results suggest that PIA may help decrease the likelihood of the development of metastatic disease in patients who are diagnosed with stage II or III CRC. The study was limited by the number of patients available, which was not large enough to allow consideration of all possible confounders. Further study of the effects of PIA in a translational and clinical setting including a larger, prospective trial of PIA in stage II/III CRC may lead to further insight into this question. [Table: see text] No significant financial relationships to disclose.