|
Feasibility and cost-effectiveness of sentinel lymph node radiolocalization in stage NO head and neck cancer |
Kosuda S, Kusano S, Kohno N, Ohno Y, Tanabe T, Kitahara S, Tamai S |
|
|
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 sentinel lymph node (SN) radiolocalisation, using scintigraphic mapping and gamma probe radiolocalisation with biopsy, in patients with stage N0 head and neck squamous cell carcinoma (HNSCC). Ipsilateral neck dissection would only follow if the biopsy result were positive for micrometastasis. This intervention was compared with ipsilateral neck dissection with no prior micrometastasis assessment.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised patients with stage N0 HNSCC.
Setting The setting was secondary care. The economic study was carried out in Japan.
Dates to which data relate The authors did not report the dates when they carried out their study. The studies included in the review dated from 1996 to 2001. The dates to which the prices related were not reported.
Source of effectiveness data The authors derived the effectiveness data from a pooled analysis of individual level data from a review of several studies, including their own.
Study sample No sample size seems to have been determined in the planning phase of the study. Eleven consecutive patients were enrolled in the study and all underwent SN radiolocalisation. The patients in the sample were aged between 42 and 76 years.
Study design The study was a case series study that was undertaken in a single centre.
Analysis of effectiveness All the patients included in the study were accounted for in the analysis. The outcome assessed in the analysis was the sensitivity of SN navigation surgery on a patient-by-patient basis and on a node-by-node basis.
Effectiveness results All but one SN was accurately identified by gamma probe radiolocalisation. The sensitivity of SN navigation surgery in the series was 100% (11 of the 11 patients) on a patient-by-patient basis and 94% (17 of 18 nodes) on a node-by-node basis.
Clinical conclusions In this case series study of 11 patients, all 11 patients were correctly diagnosed using SN navigation surgery.
Modelling To determine the expected cost-savings, a decision tree was designed based on the two competing strategies (neck dissection and SN navigation surgery). It was assumed that the prevalence of neck micrometastasis was 30%. The neck dissection strategy assumed that all patient underwent elective neck dissection. The SN navigation strategy assumed that every patient with stage N0 HNSCC first underwent SN biopsy with lymphoscintigraphy and gamma probe radiolocalisation. Then, patients with a biopsy result positive for micrometastasis underwent neck dissection. A "wait and see" policy was followed when the biopsy result was negative for micrometastasis, and subsequent salvage neck dissection was performed only when clinical evidence of metastases emerged.
Outcomes assessed in the review The outcomes assessed in the review were the sensitivity and the negative predictive value of SN navigation surgery for detecting micrometastasis. The authors also used another study to determine the mortality rate of neck dissection.
Study designs and other criteria for inclusion in the review The studies included in the review were case series studies that also evaluated small numbers of patients. Only those studies evaluating SN navigation surgery using technetium Tc 99m colloid were included 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 Six studies (including the study performed by the authors) were included in the review. Another study was used to derive the mortality rate of neck dissection.
Methods of combining primary studies The authors performed a pooled analysis of individual level data from the different studies on SN navigation surgery (74 patients in total).
Investigation of differences between primary studies Results of the review From the pooled analysis, the sensitivity of SN navigation surgery for detecting micrometastasis was 93% and the negative predictive value was 98%. The mortality of neck dissection was 1%.
Measure of benefits used in the economic analysis No summary benefit measure was used in the economic analysis. In effect, a cost-consequences analysis was undertaken.
Direct costs The costs and the quantities were not reported separately. The direct costs of the hospital were included in the analysis. These covered lymphoscintigraphy, SN biopsy, neck dissection, and labour (surgeons, anaesthesiologists, pathologists, nuclear medicine specialists and nurses) costs, and the fixed costs of the gamma probe. The costs referred to billed costs based on the Japanese national insurance reimbursement system. Future costs were discounted at a rate of 5%, as it was assumed that all patients with micrometastasis would have clinically positive nodes within 2 years following primary tumour resection. The dates to which the price data referred were not reported.
Statistical analysis of costs The costs were treated deterministically (i.e. they were treated as point estimates).
Indirect Costs The indirect costs were not included in the analysis.
Currency US dollars ($) and Japanese yen (Y). The cost in US$ was calculated using a conversion rate of Y120 = $1.
Sensitivity analysis A one-way sensitivity analysis was performed in which the prevalence of micrometastasis was varied from 0 to 100%.
Estimated benefits used in the economic analysis The model found that the introduction of navigation surgery would avoid 7 surgical deaths per 1,000 patients who were supposed to undergo neck dissection in the neck dissection strategy.
Cost results The introduction of the SN navigation surgery strategy in place of ipsilateral neck dissection strategy would yield cost-savings of $1,218 per stage N0 patient in Japan.
Synthesis of costs and benefits The costs and benefits were not combined since a cost-consequences analysis was undertaken. The results from the one-way sensitivity analysis showed that, as the prevalence of micrometastasis increases, the cost-savings per patient for the SN navigation surgery strategy are reduced. With a prevalence of above 90%, the neck dissection strategy becomes the cheaper option. A break-even point analysis for the SN navigation surgery strategy showed that the patient number requiring a break even point increases as the prevalence of micrometastasis increases. Hence more patients are needed for savings to begin to accrue.
Authors' conclusions Sentinel lymph node (SN) navigation surgery using scintigraphic mapping and gamma probe radiolocalisation was logistically feasible and cost-effective in patients with stage N0 head and neck squamous cell carcinoma (HNSCC).
CRD COMMENTARY - Selection of comparators A justification was given for using ipsilateral neck dissection as the comparator. It represented current practice in the authors' setting. You should decide if this is a widely used health technology in your own setting.
Validity of estimate of measure of effectiveness Since the study results were derived from only 11 patients, the authors performed a pooled analysis of individual data from different studies, including their own, to determine the sensitivity and specificity of SN navigation surgery. Thus, data from 74 patients were used. Even though the authors did not give much detail of their methodology, it would appear that the studies used were comparable, as they used similar populations and all those investigating SN navigation surgery used Tc 99m colloid. However, it was unclear whether the authors performed a systematic review of the literature to identify all relevant research and minimise biases. Although the authors found that the sensitivity of the SN navigation surgery strategy was 93% and the specificity was 98%, in the model they used values of 90% (sensitivity) and 100% (specificity), respectively. It is unclear if this difference could affect the authors' results in any way. Assumptions about the prevalence rate of micrometastasis were appropriately varied in the sensitivity analysis.
Validity of estimate of measure of benefit The costs and benefits were not combined. In effect, a cost-consequences analysis was undertaken.
Validity of estimate of costs All the categories of cost relevant to the perspective of the hospital were included in the analysis. Some relevant costs (e.g. regulatory costs, disposable materials, overheads and maintenance costs) were not included in the study, as the authors believed that the cost increase from the introduction of the SN technology would be small in the nuclear medicine department. The costs and the quantities were not reported separately, which will limit the generalisability of the authors' results. The unit costs were obtained from billed costs based on the Japanese national insurance reimbursement system. A sensitivity analysis of the costs was not conducted, which may limit the interpretation of the study findings and hamper the generalisability of the authors' results. The authors performed appropriate currency conversions and quoted the exchange rate used. All the costs were appropriately discounted at a rate of 5%. The dates to which the prices related were not reported, which will limit any possible reflation exercises.
Other issues The authors made appropriate comparisons of their findings with those from other studies. The authors warned the reader that the strategies, costs and variables used in the present study are unlikely to be applicable to other countries. Nevertheless, they believe that SN navigation surgery strategies would be cost-effective in other countries. The authors do not appear to have presented their results selectively, and their conclusions seem to reflect the scope of the analysis. No further limitations to the study were reported.
Implications of the study The authors mentioned that sentinel navigation surgery may be criticised because the examination of intraoperative biopsy of SN may underestimate the true incidence of micrometastasis. However, they stated in their conclusion that SN navigation surgery appears to be technically feasible considering the high sensitivity and negative predictive value.
Bibliographic details Kosuda S, Kusano S, Kohno N, Ohno Y, Tanabe T, Kitahara S, Tamai S. Feasibility and cost-effectiveness of sentinel lymph node radiolocalization in stage NO head and neck cancer. Archives of Otolaryngology Head and Neck Surgery 2003; 129(10): 1105-1109 Other publications of related interest Lenz M, Kersting Sommerhoff B, Gross M. Diagnosis and treatment of the N0 neck in carcinomas of the upper aerodigestive tract: current status of diagnostic procedures. European Archives of Otorhinolaryngology 1993;250:432-8.
Kowalski LP, Medina JE. Nodal metastases; predictive factors. Otolaryngologic Clinics of North America 1998;31:621-37.
Lowe VJ, Boyd JH, Dunphy FR, et al. Surveillance for recurrent head and neck cancer using positron emission tomography. Journal of Clinical Oncology 2000;18:651-8.
Indexing Status Subject indexing assigned by NLM MeSH Adult; Aged; Carcinoma, Squamous Cell /diagnosis /economics /surgery; Cost-Benefit Analysis; Decision Trees; Feasibility Studies; Female; Head and Neck Neoplasms /diagnosis /economics /surgery; Humans; Lymph Nodes /pathology /radionuclide imaging /surgery; Lymphatic Metastasis; Male; Middle Aged; Neck Dissection /economics; Neoplasm Staging; Sensitivity and Specificity; Surgery, Computer-Assisted /economics AccessionNumber 22003001402 Date bibliographic record published 31/07/2004 Date abstract record published 31/07/2004 |
|
|
|