Cancer population norms using a new value set for the SF-6Dv2 based on the preferences of patients with breast or colorectal cancer in Quebec.

BACKGROUND: Because health resources are limited, health programs should be compared to allow the most efficient ones to emerge. To that aim, health utility instruments have been developed to allow the calculation of quality-adjusted life-year (QALY). However, generic instruments, which can be used by any individual regardless of their health profile, typically consider the preferences of the general population when developing their value set. Consequently, they are often criticized for lacking sensitivity in certain domains, such as cancer. In response, the latest version of the Short Form 6-Dimension (SF-6Dv2) has been adapted to suit the preferences of patients with breast or colorectal cancer in the Canadian province of Quebec. By extension, our study's aim was to determine cancer population norms of utility among patients with breast or colorectal cancer in Quebec using the SF-6Dv2.

METHOD: To determine the cancer population norms, we exploited the data that were used in the development of a new value set for the SF-6Dv2. This value set was developed considering the preferences of patients with breast or colorectal cancer. Stratification by time of data collection (i.e., T1 and T2), sociodemographic variables (i.e., age, sex, body mass index, and self-reported health problems affecting quality of life), and clinical aspects (i.e., cancer site, histopathological classification, cancer stage at diagnosis, modality, and treatment characteristics) was performed.

RESULTS: In 353 observations, patients were more likely to have negative utility scores at T1 than at T2. Males had higher mean utility scores than females considering type of cancer and comorbidities. Considering the SF-6Dv2's dimensions, more females than males reported having health issues, most which concerned physical functioning. Significant differences by sex surfaced for all dimensions except "Role Limitation" and "Mental health." Patients with multifocal cancer had the highest mean and median utility values in all cancer sites considered.

CONCLUSION: Cancer population norms can serve as a baseline for interpreting the scores obtained by a given population in comparison to the situation of another group. In this way, our results can assist in comparing utility scores among cancer patients with different sociodemographic groups to other patients/populations groups. To our knowledge, our identified utility norms are the first for patients with breast or colorectal cancer from Quebec.