Validity of information obtained from a method for estimating cancer costs from the perspective of patients and caregivers.

PURPOSE: We describe a method we developed for estimating cancer costs from the perspective of patients and caregivers and evidence supporting validity of estimates obtained.
METHODS: To increase validity, interview questions were anchored to treatments; costs were divided into their components; most questions focused on facts; and the research team combined responses into cost estimates. Evidence for validity comes from a prospective study of breast cancer costs using this method.
RESULTS: Estimates obtained using interview responses were similar to those from independent sources. Women reported being reimbursed $205 on average for prosthesis (government reimbursement =$200); paying $15.48 per night at cancer lodge (average rate =$17.52); receiving government illness insurance for 14.6 weeks at 53% of usual salary (governmental program covers 15 weeks at 55%). A priori hypotheses about relations of costs with other characteristics were also confirmed. For example, patients' weekly travel costs increased as a function of distance from the radiotherapy center, with patients living <25, 25-49 and ≥50 km away spending $54, $141 and $240, respectively (P<.0001); and the proportion of annual salary lost was 37% for self-employed workers compared to 18% for employees (P<.0001).
CONCLUSIONS: Evidence to date supports the validity of estimates obtained using this method. © Springer Science+Business Media B.V. 2010