In Reply: Our study of aspirin use and survival after diagnosis of colorectal cancer was conducted among participants enrolled in the Health Professionals Follow-up Study as well as the NHS. We agree with Ms Coghill and colleagues that maintaining high rates of participant follow up are critical for an analysis of a prospective cohort. Thus, we consider our follow-up rate, which exceeded 92%, a major strength of the study. Moreover, we believe that the participants drew from their health professional backgrounds to provide accurate reports of diagnoses on each biennial follow-up questionnaire. As a result, self-reports of colorectal cancer are nearly all verified by medical record review.
Chan AT, Ogino S, Fuchs CS. Aspirin Use, Colorectal Cancer Survival, and Loss to Follow-up—Reply. JAMA. 2009;302(23):2549-2550. doi:10.1001/jama.2009.1825