Immunohistochemical testing for colon cancer--what do New Zealand surgeons know?

8-12% of colorectal cancers are associated with genetic syndromes. The most common of these is Lynch syndrome (also known as Hereditary Non-Polyposis Colorectal Cancer). Clinical criteria (Besthesda criteria) exist that can be used to identify colorectal cancer patients who may benefit from immunohistochemical screening of their tumour for Lynch syndrome. Treating surgeons need to know these criteria in order to request appropriate testing. The aim of this study was to assess the knowledge of New Zealand surgeons about the Bethesda criteria.

We conducted a postal survey of all New Zealand General Surgical Fellows of the Royal Australasian College of Surgeons.

Of the surgeons returning surveys 88% knew screening using immunohistochemistry was available; 7% would not refer an abnormal result to a genetic service. Results of the practice based questions showed only 45% of respondents knew that a colorectal cancer diagnosed before the age of 50 was one of the Besthesda criteria. The correct response rates for the rest of the survey ranged from 32-96%. Questions about Lynch syndrome associated cancers returned fewest correct answers. In general, surgeons are poorly informed about cancers associated with Lynch syndrome.

The study demonstrates limited awareness of the Besthesda criteria amongst New Zealand General Surgeons. Those treating colorectal cancer should be aware of the classic features of Lynch syndrome and test appropriately.