Background: In this study, the potential impact of a new national guideline for adjuvant systemic therapy in breast cancer (introduced in The Netherlands in 1998) was assessed, as well as the modifications of this guideline, issued in 2001. Both the change in total number of patients eligible for adjuvant therapy, as well as the cost-effectiveness of the changed clinical management of these patients were analysed.
Patients and methods: Percentages of patients who would be eligible for adjuvant therapy in 1994, 1998 and 2001 were estimated, based on clinical data from 127 patients, who were operated on in 1994. Ten-year overall survival rates were used as a measure of effectiveness, based on the two most recent EBCTCG meta-analyses. Actual resource costs were calculated. With a decision analytic model, the incremental cost-effectiveness ratios (1998 versus 1994, and 2001 versus 1998) were calculated.
Results: The introduction of the 1998 guideline resulted in a relative increase of 80% in the total number of patients eligible for adjuvant therapy, compared with 1994 (from 40% to 72% of all patients with primary breast cancer). With an estimated absolute increase of 10-year overall survival of 2%, the 1998 guideline was found to have an expected incremental cost-effectiveness ratio of about 4837 per life-year gained.
Conclusions: Introduction of the new guideline considerably affected the number of patients eligible for adjuvant systemic therapy for breast cancer. The associated incremental cost-effectiveness ratio is well within the range of values that are generally considered acceptable.