|Adrenal mass evaluation in patients with lung carcinoma: a cost-effectiveness analysis
|Remer E M, Obuchowski N, Ellis J D, Rice T W, Adelstein D J, Baker M E
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.
Strategies for adrenal mass evaluation in patients with lung carcinoma. The following strategies were evaluated: (1) CT (0 H) followed by MR imaging followed by CT biopsy; (2) CT (10 H) followed by MR imaging followed by CT biopsy; (3) CT (0 H) followed by CT biopsy; (4) CT (10 H) followed by CT biopsy; (5) MR imaging followed by CT (0 H) followed by CT biopsy; (6) MR imaging followed by CT (10 H) followed by CT biopsy; (7) MR imaging followed by CT biopsy.
Economic study type
Patients with newly diagnosed lung carcinoma and an adrenal mass identified on initial CT after IV contrast material was administered. All patients with benign adrenal lesions had respectable primary tumours. Patients were asymptomatic, had pulmonary reserve and general health to tolerate thoracotomy, and did not have clinically evident nodal disease involving extrathoracic regions, vessels or nerves.
Hospital. The economic study was carried out in the USA.
Dates to which data relate
Effectiveness and resource use data were collected from studies previously published between 1982 and 1996. Cost data were derived from a 1998 source. The price year was 1998.
Source of effectiveness data
Effectiveness data were derived from a review/synthesis of previously completed studies.
A decision-tree was used to determine the cost-effectiveness of the 9 imaging and biopsy strategies.
Outcomes assessed in the review
The review assessed the following outcomes: accuracy of MR imaging, CT, and biopsy; average life expectancy, and surgical mortality rates.
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
At least 17 studies were included in the review.
Methods of combining primary studies
Investigation of differences between primary studies
Results of the review
The prevalence of adrenal metastasis from lung carcinoma at presentation was 10%. The sensitivity and specificity of MR imaging were 0.81 and 1, respectively. The sensitivity and specificity of CT (0 H) were 0.54 and 1, respectively. The sensitivity and specificity of CT (10 H) were 0.73 and 0.96, respectively. The sensitivity and specificity of biopsy were 0.90 and 0.99, respectively. Mortality from thoracotomy was 4%. Life expectancy for patients with resectable lung cancer following thoracotomy was 4.45 years. If these patients are inappropriately not treated, their life expectancy falls to 2.64 years. Untreated patients, receiving best supportive care, with distant metastasis have an average survival of 0.35 years. Those who have adrenal metastasis, and who inappropriately undergo thoracotomy, have no additional benefit over those who do not undergo surgery.
Measure of benefits used in the economic analysis
Life expectancy was used as the measure of benefit. The authors stated that benefits were discounted, but did not specify the discount rate.
The authors stated that costs were discounted, but did not specify the discount rate. Quantities and costs were reported separately. Direct costs reflected professional and technical reimbursements incurred by MR imaging, CT, biopsy, and surgery. The quantity/cost boundaries adopted were those of society and hospital. The estimation of quantities and costs was based on actual data. Medicare reimbursement was used as a proxy for costs. The price year was 1998.
A one-way sensitivity analysis was conducted on all baseline parameters. The effect of various degrees of correlation between CT and MR imaging was evaluated. Additionally, two-way sensitivity analyses were carried out.
Estimated benefits used in the economic analysis
Life expectancy of the 9 imaging and biopsy strategies varied between 2.43 and 3.87 years.
Total costs of the 9 imaging and biopsy strategies varied between $18,333 and $20,809.
Synthesis of costs and benefits
CT (10 H) followed by MR imaging if needed was the most cost-effective strategy. The incremental cost-effectiveness of CT (10 H) followed by MR imaging if needed over CT (10 H) followed by biopsy was $16,370. Other strategies became more cost-effective depending on the sensitivities of MR imaging and CT and the specificity of CT; the relative costs of CT and MR imaging; the cost of surgery; and the pretest probability of adenoma. If CT and MR imaging are highly correlated, other strategies become more cost-effective, depending on the degree of correlation. The two-way sensitivity analysis showed that other strategies become more cost-effective at low sensitivities of CT (10 H) and low costs of MR imaging.
Unenhanced CT using a 10 H threshold followed by MR imaging, if needed, was the most cost-effective strategy for evaluating an adrenal mass in a patient with newly diagnosed non-small cell lung cancer.
CRD COMMENTARY - Selection of comparators
A justification was given for the comparators used, namely imaging and biopsy strategies. You, as a user of this database, should decide if these health technologies are relevant to your setting.
Validity of estimate of measure of benefit
The authors did not state that a systematic review of the literature had been undertaken. More details could have been provided about the conduct of the review, and the design and method of combination of the primary studies. Estimation of benefits was obtained directly from the effectiveness analysis using modelling techniques.
Validity of estimate of costs
All categories of costs relevant to the perspective adopted were included in the analysis. The cost of treating subsequently diagnosed metastatic disease was not considered. Quantities and costs were reported separately. Charges were used to proxy prices. The price year was reported.
The authors stated that costs and benefits had been discounted, but provided no further details. A set of two-way sensitivity analyses was performed to account for the uncertainties in the data. Given that this was the first study on the subject, the authors could not compare their findings with those from other studies. The issue of generalisability to other settings was not addressed. The authors did not present their results selectively. The study considered patients with newly diagnosed non-small cell lung cancer and this was reflected in the authors' conclusions. The authors reported the following limitations: potential biopsy-related complications were not considered; the decision tree was intentionally simplified; non-operative therapy was excluded from the analysis; and, finally, the patient or referring clinician may not wish to accept two imaging studies after an initial CT revealing the lung mass, before proceeding to biopsy.
Implications of the study
A further study using serial CT and MR imaging is necessary to determine the true degree of correlation. Given that differences in cost-effectiveness between the strategies were moderate, other issues should also be considered in the decision making process.
Remer E M, Obuchowski N, Ellis J D, Rice T W, Adelstein D J, Baker M E. Adrenal mass evaluation in patients with lung carcinoma: a cost-effectiveness analysis. American Journal of Roentgenology 2000; 174(4): 1033-1039
Other publications of related interest
1. Evans W K, Will B P, Berthelot J M, Wolfson M C. Diagnostic and therapeutic approaches to lung cancer in Canada and their costs. British Journal of Cancer 1995;72(5):1270-1277.
2. Langer C J, Rosvold E. Newer aspects in the diagnosis, treatment, and prevention of non-small cell lung cancer Part II. Current Problems in Cancer 1996;20(4):217-79.
Subject indexing assigned by NLM
Adrenal Gland Neoplasms /diagnosis /secondary; Biopsy; Carcinoma, Non-Small-Cell Lung /diagnosis; Cost-Benefit Analysis; Decision Trees; Humans; Lung Neoplasms /pathology; Magnetic Resonance Imaging /economics; Sensitivity and Specificity; Tomography, X-Ray Computed /economics
Date bibliographic record published
Date abstract record published