Explanations of risk in families without identified mutations for hereditary nonpolyposis colorectal cancer

Purpose: Genetic testing for hereditary forms of cancer does not always identify a causative mutation. Little is known about personal or family response to these indeterminate results when a hereditary form of cancer is suspected. This study explored thoughts about and responses to risk for hereditary nonpolyposis colorectal cancer (HNPCC) when a family member has received indeterminate genetic test results. Design: In this qualitative study, data were gathered from index cases who received indeterminate genetic test results through a longitudinal study offering genetic counseling and testing for HNPCC. First-degree relatives of these indeterminate index cases were also invited to participate in the qualitative interview. Methods: Semistructured telephone interviews were conducted with index cases and their at-risk first-degree relatives. Data were analyzed using the within- and across-case method. Findings: The across-case analysis led to the development of the Awareness and Surveillance Trajectory, which describes individual interpretations of and responses to risk, based on personal and family history. Explanations of risk addressed the meaning of cancer in the family and provided context for individual interpretations. They were identified using within-case analysis and organized into a typology: innate, exceptional, idiosyncratic, and undeveloped explanations. Conclusions: Members of families without identified HNPCC mutations vary in their explanations for, interpretations of, and responses to indeterminate genetic test results. Clinical Relevance: Explanations of family risk and interpretations of individual risk offer healthcare providers valuable information. In combination with the Awareness and Surveillance Trajectory, assessment of these beliefs can facilitate development of individualized recommendations and strategies for possible preventive actions.