To the Editor: In November 1999, the National Health and Medical Research Council (NHMRC) released Guidelines for the prevention, early detection and management of colorectal cancer.1 One chapter addressed screening for colorectal cancer (CRC), citing Level 1 evidence in support of faecal occult blood testing (FOBT) as the preferred modality for population-based CRC screening. Colonoscopy and sigmoidoscopy were not recommended. In a postal survey conducted in 1998, before release of these guidelines, we found mixed views among Australian surgeons about CRC screening.2

In February 2001, we conducted a follow-up (post-guidelines) survey which included three questions about CRC screening that had been asked in the pre-guidelines survey. Using a pre–post design, we evaluated the impact of the NHMRC guidelines on surgeons' views.

Of the 172 surgeons confirmed still to be in active practice at the time of follow-up, 114 (66%) returned questionnaires. One hundred and three (90%) agreed to matching of their baseline and follow-up responses. Of these, 101 (98%) provided valid responses to each of the three questions on both occasions.

Surgeons' views about population-based CRC screening by FOBT changed significantly between the surveys (Box). At baseline, half "strongly agreed" or "agreed" that population-based FOBT should be introduced for all Australians over the age of 50 years. At follow-up, the proportion had increased significantly to more than two-thirds (McNemar's χ2 = 13.0; P < 0.001). There was no significant change in the percentage of surgeons who "strongly agreed" or "agreed" that colonoscopy is preferable to FOBT (McNemar's χ2 = 0.9; P = 0.3). In contrast, there was a significant decrease in the percentage who "strongly agreed" or "agreed" that sigmoidoscopy is preferable to FOBT (McNemar's χ2 = 4.4; P = 0.04).

Although the influence of events unrelated to the NHMRC guidelines cannot be entirely excluded from uncontrolled evaluation designs such as this, our data provide some reassurance that the guidelines have had an impact. However, as argued elsewhere,3 substantially more effort is required to ensure that patients with CRC detected through screening receive evidence-based management. More rigorous study designs with control groups are recommended to identify strategies effective in changing surgical practice. Finally, surgeons' increased enthusiasm for CRC screening contrasts with public hesitancy.4