Colorectal tumour microsatellite instability test results: perspectives from patients

To determine which individuals with colorectal cancer (CRC) were interested in knowing the results of their tumour microsatellite instability (MSI) and immunohistochemistry (IHC) testing. We were also interested in the patients' reasons for choosing to learn their results and in the impact of those results on overall self-assessed quality of life.

CRCs from 414 individuals were assayed for MSI and IHC for DNA mismatch repair gene products (MLH1, MSH2, MSH6). Individuals were invited to learn their MSI/IHC results. They randomly received either brief or extended educational materials about the testing and a pretest survey to learn reasons for their interest and to assess their pretest quality of life.

Of the 414 individuals, 307 (74%) chose to learn their results. There was no significant difference in interest in knowing test results according to gender, age, educational level, or family history of colon cancer. The level of detail in the information piece received by the patients did not influence their desire to know their test results. Self-assessed quality of life was not altered by receiving results and was not correlated with the test outcome.

Individuals with colorectal cancer had a high level of interest in learning their individual MSI/IHC test results and did not seem deterred by the inherent complexity or ambiguity of this information. Regardless of test outcome, results did not significantly affect self-assessed quality of life. Further studies are needed to assess comprehension of results and behavioural changes resulting from the learning of MSI/IHC results.