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A cost-outcome analysis of adjuvant postmastectomy locoregional radiotherapy in premenopausal node-positive breast cancer patients |
Dunscombe P, Samant R, Roberts G |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology The use of adjuvant, postmastectomy, locoregional radiotherapy for lymph-node-positive breast cancer. The intervention delivered radiotherapy to the chest wall and adjacent lymph-node regions with a 4-field technique.
Economic study type Cost-effectiveness and cost-utility analyses.
Study population The study population comprised premenopausal node-positive breast cancer patients.
Setting The setting of the study was a hospital. The economic study was carried out in Ontario, Canada.
Dates to which data relate The effectiveness and resource use data were derived from studies published in 1997 and 1999. The price year was 1997.
Source of effectiveness data The effectiveness evidence was derived from published studies.
Modelling A spreadsheet-based model was used to assess the overall costs associated with the adjuvant radiotherapy. The model simulated the costing of a facility treating 1,600 patients per year.
Outcomes assessed in the review The outcomes assessed from the published studies were the incremental survival in terms of life-years and a utility score.
Study designs and other criteria for inclusion in the review Sources searched to identify primary studies Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Number of primary studies included The effectiveness evidence was derived from three primary studies.
Methods of combining primary studies Investigation of differences between primary studies Results of the review Adjuvant, locoregional, postmastectomy radiotherapy showed an improved survival of 9 to 10% at 10 years. Therefore, the life-years gained (and discounted at 5%) were 0.5.
The utility score was 0.9.
Measure of benefits used in the economic analysis The benefit measures used in the economic analysis were the life-years and quality-adjusted life-years (QALY) gained. Both were derived from the effectiveness analysis. A 5% discount rate was used.
Direct costs A 5% discount rate was used for the costs included in the model, even though the time horizon of the analysis appears to have been one year. The quantities of resources and the unit costs were not reported. The cost/quantity boundary adopted was that of the institution. A course of radiotherapy included initial medical assessment, mold room activities, simulation, treatment planning, one fraction of radiation treatment, and follow-up. It was assumed that the cost of providing radiotherapy was limited to the cost of the radiotherapy itself, and that the follow-up interventions had identical costs regardless of whether radiotherapy was provided or not. The costs were estimated using actual data derived from the 1997 budget for the Northeastern Ontario Regional Cancer Centre. The resource use was derived from studies published in 1997 and 1999. The price year was 1997.
Statistical analysis of costs No statistical analyses were conducted.
Indirect Costs The indirect costs were not included in the analysis.
Sensitivity analysis Several sensitivity analyses were conducted due to uncertainty around the input data. In the one-way sensitivity analyses, the model parameters varied were the treatment time (which was doubled), discount rate for survival data (10%), and utility score (0.8). A two-way sensitivity analysis was also carried out, varying both the utility score (0.8) and the number of life-years gained (0.4).
Estimated benefits used in the economic analysis The discounted life-years gained were 0.5 and the discounted QALYs gained were 0.45.
Cost results The average cost of the adjuvant radiotherapy over no adjuvant radiotherapy was Can$6,700.
Synthesis of costs and benefits Cost-effectiveness and cost-utility analyses were performed to combine the costs and benefits. An incremental analysis was performed since the cost-effectiveness ratios reported represented the extra cost per benefit, and the extra benefit of radiotherapy, in comparison with the strategy of surgery and chemotherapy without any adjuvant radiotherapy. The cost per life-year of radiotherapy was Can$14,000 and the cost per QALY was Can$15,600. The estimated cost-effectiveness and cost-utility ratios were particularly sensitive to concomitant variations in both the utility score and the number of life-years gained.
Authors' conclusions "Within the context of generally accepted medical expenditures, adjuvant post mastectomy locoregional radiotherapy for premenopausal node-positive breast cancer patients would be regarded as a cost-effective treatment strategy."
CRD COMMENTARY - Selection of comparators The rationale for the choice of the comparator was not explicit, but relatively clear. A strategy of surgery and chemotherapy without any adjuvant radiotherapy appeared, from the paper's introductory discussion, to be accepted practice. You should assess whether it represents a widely used health intervention in your own setting.
Validity of estimate of measure of effectiveness The analysis of effectiveness used data derived from a small number of published studies. However, a review of the literature was not undertaken. In addition, details of the primary studies were not reported, especially in terms of the methods of combining the effectiveness data and dealing with potential differences among the study populations. However, sensitivity analyses were conducted to overcome variability in data and uncertainty around some specific variables.
Validity of estimate of measure of benefit The benefit measures used in the economic analysis (life-years and QALYs) appear to have been appropriate to assess the health impact of the intervention. Both were discounted.
Validity of estimate of costs All the categories of costs relevant to the perspective adopted appear to have been included in the analysis, although the authors assumed that all the costs incurred in the follow-up period were similar both with and without adjuvant radiotherapy. Statistical analyses of the costs and the quantities were not conducted. The quantities of resources used and the unit costs were not reported, thus reducing transparency and the potential for generalisability. A discount rate was used, although the time horizon of the analysis was unclear. Finally, no sensitivity analyses on cost variability were conducted, other than on the discount rate.
Other issues The authors made several comparisons of their findings with those from other studies. However, the issue of the generalisability of the study results to other settings was not explicitly addressed, and few sensitivity analyses were carried out. Therefore, the external validity of the study was somewhat limited. The authors considered premenopausal node-positive breast cancer patients and this was reflected in their conclusions.
Implications of the study The authors suggest that, although adjuvant radiotherapy proved to be cost-effective, the nodal status of most premenopausal patients should be properly assessed before performing radiotherapy. Further research should focus on the impact of adjuvant radiotherapy on other patient groups, such as those women undergoing breast-conserving surgery.
Source of funding Supported by the Northern Cancer Research.
Bibliographic details Dunscombe P, Samant R, Roberts G. A cost-outcome analysis of adjuvant postmastectomy locoregional radiotherapy in premenopausal node-positive breast cancer patients. International Journal of Radiation Oncology, Biology, Physics 2000; 48(4): 977-982 Indexing Status Subject indexing assigned by NLM MeSH Breast Neoplasms /economics /radiotherapy /surgery; Canada; Cost-Benefit Analysis; Female; Humans; Lymphatic Metastasis; Mastectomy; Premenopause; Quality-Adjusted Life Years; Radiotherapy, Adjuvant /economics AccessionNumber 22000001824 Date bibliographic record published 31/01/2003 Date abstract record published 31/01/2003 |
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