OBJECTIVES

: There are currently only a few reports available on QOL data which provide the basis of QALY calculation in Japanese patients, assessments are made using overseas reports. In 2006, a utility prediction mathematical model for recurrent metastatic breast cancer was introduced by Lloyd in the U.K. In this study, we investigated if this Lloyd model can be applied to the utility prediction in Japanese patients using the QOL database for Japanese breast cancer patients.

METHODS

: We used the Lloyd model in utility prediction for recurrent metastatic breast cancer patients. In this model, utility prediction is made using patients’ age, therapeutic effects, and adverse events associated with drug therapy as parameters. For the validation set of Japanese patients, the data of recurrent metastatic breast cancer patients, such as the age and adverse events associated with drug therapy, were extracted from the QOL data base of Japanese breast cancer patients and used for the Lloyd model in order to investigate the correlation between the predicted utility and the actual utility calculated using EQ-5D-5L of the corresponding patients.

RESULTS

: Investigations were made using the data of a total of 41 patients of recurrent metastasized breast cancer for 254 assessment points out of the data of 171 patients enrolled between June 2015 and April 2018 for a total of 1200 assessment points. The correlation coefficient between the QOL value predicted from the Lloyd model using parameters obtained at 254 assessment points and the actual values of QOL with EQ-5D-5L was 0.55, suggesting that there was a positive correlation between these values.

CONCLUSIONS

: The results revealed that there was a positive correlation between the predicted utility using this model and the actual utility using EQ-5D-5L, suggesting that the Lloyd model can be applicable.