With 36,000 new cases per year, colorectal cancer ranks third in incidence among men and second among women. Treatment often involves surgery, such as a partial or total colectomy, or a rectal resection. This procedure requires a highly specialized setting. A study based on 1997 data from the Program for the Medicalization of Information Systems (PMSI) suggests that surgical activity for colorectal cancer varies greatly by facility and that approximately half of the facilities had low activity (fewer than 20 procedures) that year. However, the PMSI was not gradually extended to the entire private sector until 1997. Activity in the private sector was therefore only incompletely recorded at that time, even though it accounts for the majority of initial surgical care. It was therefore necessary to conduct a new study to assess changes in the number of facilities with low activity. (R.A.)