|
The cost-effectiveness of routine postoperative radiotherapy after sector resection and axillary dissection for breast cancer stage I: results from a randomized trial |
Liljegren G, Karlsson G, Bergh J, Holmberg L |
|
|
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 Routine postoperative radiotherapy after sector resection and axillary dissection for breast cancer stage I.
Study population The study population comprised patients with breast cancer stage I. Women aged under 80 with a unifocal breast cancer and a maximum tumour diameter of 20mm on the preoperative mammogram were eligible. Patients were eligible provided that the specimen was histopathologically free from multifocal in situ and invasive lesions outside 20mm from the border of the primary tumour. The axillary nodes had to be histopathologically free from metastases. Patients were ineligible if the tumour was transected during surgery.
Setting The study setting was hospital. The economic analysis was carried out in Sweden.
Dates to which data relate Effectiveness, resource use, and cost data were collected between October 1981 and September 1988. The price year was 1993.
Source of effectiveness data Effectiveness data were taken from a single study. Utility scores were estimated by the authors and used to model quality adjusted life-years (QALYs).
Link between effectiveness and cost data The costing was carried out prospectively on the same patient sample as that used in the effectiveness analysis.
Study sample 184 patients were randomised to the XRT group and 197 to the non-XRT group. Allocation to treatment group was stratified in blocks of four within each centre and stratum. No power calculations were reported.
Study design This was a prospective, randomised controlled trial carried out at six hospitals. Patients were followed up for five years. No patient was lost to follow-up.
Analysis of effectiveness The analysis of the clinical study was based on intention to treat. The primary health outcomes were local recurrences. The authors did not show whether the two groups were comparable in terms of demographic characteristics.
Effectiveness results The effectiveness results were as follows:
The local recurrence rate was 0.023 in the XRT group and 0.184 in the non-XRT group, (p<0.001).
Survival, (p=0.44) or regional and distant recurrence, (p=0.23) were not significantly different.
The authors defined risk groups as follows:
patients at low risk of local recurrence were defined as being aged over 60 years and without comedo or lobular carcinoma;
patients at intermediate/high risk of local recurrence were defined as being aged under 60 years or having comedo or lobular carcinoma, irrespective of age.
In the intermediate/high risk group, local recurrence was 0.73 for non-XRT and 0.97 for XRT.
In the low risk group, local recurrence was 0.941 for non-XRT and 0.99 for XRT.
Clinical conclusions The only difference at five-year follow-up between postoperative therapy and surgery alone was an increased incidence of local recurrence in the non-XRT group.
Modelling A decision tree was used to model treatment and local recurrence over a period of five years.
Methods used to derive estimates of effectiveness Utility values were based on the judgement of eight health professionals involved in breast cancer management at the participating centres.
Estimates of effectiveness and key assumptions Utility values ranged from 0.502 for secondary therapy and CMF during six months for local recurrence to 0.730 for new sector resection for local recurrence.
Measure of benefits used in the economic analysis Local recurrences and QALYs were used as the measures of health benefit. QALYs were discounted at rates of 0% and 5%.
Direct costs Direct costs were discounted at a rate of 5%. Quantities and costs were not reported separately. Direct medical costs related to primary treatment, costs for follow-up, and costs for treatment of local recurrence. The quantity/cost boundary adopted was that of the hospital. Costs were collected from the hospital. Drug costs were taken from the Swedish Pharmacy Company. The price year was 1993.
Statistical analysis of costs No statistical analysis of costs was reported.
Indirect Costs Indirect costs were discounted at a rate of 5%. Quantities and costs were not reported separately. Indirect medical costs related to travel expenses and lost productivity. The quantity/cost boundary adopted was that of society. The pricing of lost productivity was based on statistics from the National Statistics Bureau. The price year was 1993.
Currency Swedish kroner (Sek), with Sek7.6 = $1 and Sek12.5 = 1.
Sensitivity analysis Sensitivity analyses were conducted on radiotherapy costs, local recurrence rates, and QALYs.
Estimated benefits used in the economic analysis The local recurrence rate was 0.023 in the XRT group and 0.184 in the non-XRT group, (p<0.001).
In the intermediate/high risk group, local recurrence was 0.73 for non-XRT and 0.97 for XRT.
In the low risk group, local recurrence was 0.941 for non-XRT and 0.99 for XRT.
For QALY results see synthesis of costs and benefits below.
Cost results Total costs amounted to Sek120,633 in the XRT group and Sek66,187 in the non-XRT group.
Synthesis of costs and benefits The incremental cost per avoided local recurrence by routine postoperative radiotherapy was Sek337,727.
The incremental cost per avoided local recurrence by routine postoperative radiotherapy was Sek209,666 in the intermediate/high-risk group and Sek1,229,780 in the low-risk group.
The incremental cost per QALY gained was Sek1,125,721 for all patients, and Sek532,609 in the intermediate/high-risk group.
Postoperative radiotherapy was dominated in the low-risk group.
When utility values were changed, the incremental cost per QALY gained ranged from Sek205,626 to Sek3,899,335 at five years and from Sek46,435 to Sek504,549 at 20 years for all patients.
Authors' conclusions "The cost of routine postoperative radiotherapy after sector resection and axillary dissection in breast cancer stage I per avoided local recurrence and gained QALY is high. The costs per gained QALY show great variation depending on utility value."
CRD COMMENTARY - Selection of comparators A justification was given for the comparator used, namely that it represented a currently employed strategy. You, as a user of the database, should decide if these health technologies are relevant to your setting.
Validity of estimate of measure of effectiveness The analysis was based on a prospective randomised controlled trial, which was appropriate for the study question and should have a high validity. The authors did not show that the study sample was representative of the study population, and did not report any demographic characteristics. (Correspondence with the authors, however, indicates that these details are reported elsewhere (see Other Publications of Related Interest below). Specific estimates of QALYs for each strategy were not reported. The analysis of effectiveness was handled credibly.
Validity of estimate of measure of benefit The estimation of benefits was modelled. The authors did not report the instrument used to derive a measure of health benefit, and utility scores were based on estimates made by external observers.
Validity of estimate of costs Good features of the cost analysis were that all relevant direct and indirect cost categories were included; sensitivity analyses were conducted; and the price year was reported, which makes reflation exercises possible. However, quantities and costs were not reported separately; no statistical analyses were reported on quantities or costs; and cost estimates were taken from a single hospital and may not be generalisable to other settings.
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 women treated for breast cancer stage I and this was reflected in the authors' conclusions. Utility values were derived from external observers, and not from patients themselves. Follow-up was limited to five years, which is short in terms of the natural history of breast cancer.
Implications of the study According to the authors, the cost of routine postoperative radiotherapy after sector resection and axillary dissection in breast cancer stage I per avoided local recurrence and gained QALY is high. There is a need to identify risk factors for local recurrence, better understand the impact on quality of life of a local recurrence, and to add cost evaluations to clinical trials in early breast cancer.
Bibliographic details Liljegren G, Karlsson G, Bergh J, Holmberg L. The cost-effectiveness of routine postoperative radiotherapy after sector resection and axillary dissection for breast cancer stage I: results from a randomized trial. Annals of Oncology 1997; 8(8): 757-763 Other publications of related interest Liljegren G, Holmberg L, Bergh J, Lindgren A, Tabar L, Nordgren H, Adami H O, and the Uppsala-Orebro Breast Cancer Study Group. 10-year results after sector resection with or without postoperative radiotherapy for stage I breast cancer: a randomized trial. Journal of Clinical Oncology 1999; 17(8): 2326-2333.
Indexing Status Subject indexing assigned by NLM MeSH Breast Neoplasms /psychology /radiotherapy /surgery; Cost-Benefit Analysis; Female; Health Care Costs; Humans; Lymph Node Excision; Prospective Studies; Quality of Life AccessionNumber 21997001340 Date bibliographic record published 30/06/2002 Date abstract record published 30/06/2002 |
|
|
|