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A cost-effectiveness analysis of axillary node dissection in postmenopausal women with estrogen receptor-positive breast cancer and clinically negative axillary nodes |
Orr R K, Col N F, Kuntz K M |
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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 Axillary lymph node dissection in postmenopausal women with estrogen receptor-positive breast cancer and clinically negative axillary nodes.
Study population Hypothetical cohorts of postmenopausal high-risk (palpable 3-cm tumour) and low-risk (nonpalpable 1-cm tumour) women with estrogen receptor-positive breast cancer and clinically negative axillary nodes.
Setting Hospital. The economic study was set in the USA.
Dates to which data relate Effectiveness data were collected from studies published between 1985 and 1995. Resource use data were taken from studies published between 1991 and 1994. The price year was 1997.
Source of effectiveness data Effectiveness data were derived from a review of the literature and expert opinion.
Modelling A Markov decision analytic model (DATA 3.0, TreeAge) was used to determine the cost-effectiveness of the two treatment alternatives.
Outcomes assessed in the review The review assessed annual probability of recurrence, annual probability of death, annual probability of lymphedema, and chemotherapy toxicity.
Study designs and other criteria for inclusion in the review Effectiveness estimates were taken from randomised controlled trials.
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 Summary statistics from individual studies.
Number of primary studies included At least 8 primary studies were included in the review.
Methods of combining primary studies Investigation of differences between primary studies Results of the review The results of the review were as follows:
The annual probability of first recurrence was 0.03 for women with negative nodes, 0.14 for women with positive nodes (tamoxifen), 0.09 for women with positive nodes (chemotherapy first five years), and 0.14 for women with positive nodes (chemotherapy after five years).
The annual probability of death after first recurrence was 0.3. The annual probability of recurrence after first remission and of death after second recurrence was 0.7 and 0.5, respectively. The annual probability of recurrence after second remission was 0.9 and of death after third recurrence was 0.9.
The annual probability of lymphedema was 0.005.
Chemotherapy toxicity was fatal in 0.5% of cases, severe in 5% of cases, and mild in 60% of cases.
Methods used to derive estimates of effectiveness An expert panel of local oncologists and surgeons was used to derive estimates of effectiveness.
Estimates of effectiveness and key assumptions Utility values were 1 if well and no evidence of recurrence, 0.95 with ALND, 0.7 after first recurrence, 0.85 after first remission, 0.5 after second recurrence, 0.7 after second remission, 0.3 after third recurrence, 0.9 with lymphedema, and 0 with death.
Measure of benefits used in the economic analysis Quality-adjusted life years (QALYs) were used as the measure of benefits. Utility values were derived from expert opinion and utilities were discounted at an annual rate of 3%.
Direct costs Direct costs were discounted at an annual rate of 3%. Quantities and costs were reported separately. Direct costs included costs of ALND, chemotherapy, tamoxifen, recurrence, remission, lymphedema, and death. The quantity/cost boundary adopted was that of society. The estimation of quantities and costs was based on actual data. Costs and quantities were collected from published studies. The price year was 1997. Costs were updated using the medical care component of the Consumer Price Index.
Statistical analysis of costs No statistical analysis of costs was performed.
Indirect Costs Indirect costs were not included.
Sensitivity analysis A variety of sensitivity analyses were conducted on model parameters surrounding costs, utilities and probabilities of relevant clinical events.
Estimated benefits used in the economic analysis The benefits for high-risk women amounted to 10.05 QALYs with watchful waiting and 10.30 QALYs with immediate ALND. The benefits for low-risk women amounted to 11.91 QALYs with watchful waiting and 11.94 QALYs with immediate ALND.
Cost results Costs for high-risk women amounted to $51,700 with watchful waiting and $60,900 with immediate ALND. Costs for low-risk women amounted to $49,900 with watchful waiting and $58,000 with immediate ALND.
Synthesis of costs and benefits The incremental cost-effectiveness of immediate ALND over watchful waiting was $36,700 per QALY gained for high-risk women and $308,000 per QALY gained for low-risk women. These results were sensitive to changes in the probability of a patient receiving chemotherapy if axillary nodes were histologically positive, tumour size and palpability, patient age, and surgical practice related to lumpectomy and ALND.
Authors' conclusions Immediate ALND results in considerable benefit at a reasonable cost for most women with palpable tumours. Because the benefits are lower in patients with nonpalpable tumours, ALND should not be considered mandatory for that subgroup.
CRD COMMENTARY - Selection of comparators A justification was given for the comparators used, namely a currently employed strategy. You, as a user of the database, should decide if these health technologies are relevant to your setting. Another new potential comparator, namely sentinel lymphadenectomy, was not considered due to lack of available data.
Validity of estimate of measure of benefit The authors did not state that a systematic review of the literature had been undertaken. More information about the design of the review and the method of combining primary effectiveness estimates could also have been reported. Estimation of benefits was obtained directly from the effectiveness analysis and utility estimates by a Delphi panel of oncologists. The authors made some simplifying assumptions, in that they did not consider local breast recurrence after segmental resection and radiotherapy, or performing ALND at the time of total mastectomy.
Validity of estimate of costs Some good features of the cost analysis were that all relevant cost categories were included, sensitivity analyses were conducted on costs and quantities, quantities and costs were reported separately, and the price year was reported. It was unclear, however, whether charges were used to proxy prices and this would limit the generalisability of the cost data. The authors did not report how the costs associated with death were calculated.
Other issues The authors did make appropriate comparisons of their findings with those from other studies, but did not address the issue of generalisability to other settings. The authors do not appear to have presented their results selectively. The study considered postmenopausal women with estrogen receptor-positive breast cancer and clinically negative axillary nodes and this was reflected in the authors' conclusions. The results are only applicable to this subgroup of women.
Implications of the study The authors suggest that decisions about ALND should be based on patient age, tumour size and palpability, individual patient preferences, the likelihood of receiving post-operative chemotherapy, and other prognostic factors.
Bibliographic details Orr R K, Col N F, Kuntz K M. A cost-effectiveness analysis of axillary node dissection in postmenopausal women with estrogen receptor-positive breast cancer and clinically negative axillary nodes. Surgery 1999; 126(3): 568-576 Indexing Status Subject indexing assigned by NLM MeSH Age Factors; Aged; Antineoplastic Agents /therapeutic use; Axilla; Breast Neoplasms /drug therapy /metabolism /surgery; Chemotherapy, Adjuvant; Combined Modality Therapy; Cost-Benefit Analysis; Female; Humans; Lymph Node Excision /economics; Lymphatic Metastasis; Markov Chains; Menopause; Middle Aged; Models, Biological; Neoplasms, Hormone-Dependent /drug therapy /metabolism /surgery; Probability; Prognosis; Receptors, Estrogen /metabolism AccessionNumber 21999001658 Date bibliographic record published 31/05/2001 Date abstract record published 31/05/2001 |
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