P. Quinn1, J. Oliver1, O. Mahmoud1, R. Chokshi1 1Rutgers New Jersey Medical School,Newark, NJ, USA
Introduction:
While sentinel lymph node biopsy (SLNB) has been established as a useful tool in the staging of melanoma, its utility in cutaneous squamous cell carcinoma (CSCC) has yet to be elucidated. Analysis has shown that SLNB may have an emerging role in patients with high-risk lesions. The purpose of this study was to determine the cost-effectiveness of performing SLNB in all head and neck CSCC patients as well as by TNM staging.
Methods:
A decision model was developed to analyze costs and survival in head and neck CSCC patients based on their tumor and nodal metastasis staging and whether or not they received a SLNB. The decision model placed patients into two groups, those undergoing SLNB and those undergoing only wide local excision. Those that were found to have any positive lymph node underwent a neck dissection, then those with N2 disease were treated with radiation therapy and those with N3 disease were treated with chemotherapy and radiation based on treatment guidelines according to the National Comprehensive Cancer Network. Values for disease stage, morbidity, mortality as well as SLNB sensitivity and specificity were derived from the published literature. Costs were derived using Medicare outpatient costs (FY 2018). Survival values were calculated with the declining exponential approximation of life expectancy (DEALE) method using available data on disease-specific death rate. The average age of patients with CSCC was found to be 70, with a life expectancy of 14.3 years according to Social Security life tables. Incremental cost-effectiveness ratios (ICER) were calculated based on the change in quality adjusted life years (QALYs) and costs (US$) between the different options, with a threshold of $100,000 to determine the most cost-effective strategy. One-way and two-way sensitivity analysis was performed to validate the results.
Results:
Sensitivity and specificity of SLNB was found to be 77% and 100%. The disease incidence was 77%, 5%, and 18% for T1, T2, and T3 specifically, and the rate of node positivity was 0.4%, 12.2%, and 14.1% for each T stage. Not performing a SLNB results in 12.26 QALYs and a cost of $3,712.98. Performing a SLNB resulted in a 0.59 decrease in QALYs and an increase in cost of $1,379.58 for an ICER of -2,338.27. This trend remained the same across all tumor stages. Sensitivity analysis of tumor stage distribution, nodal stage distribution, nodal positivity rates, and SLNB sensitivity did not alter the outcome.
Conclusion:
In patients with head and neck cutaneous squamous cell carcinoma, the most cost-effective strategy is to not perform sentinel lymph node biopsies, regardless of the patient’s stage. Low rates of nodal metastasis in addition to low disease-specific death rates were the significant factors in this outcome. Increasing the sensitivity of SLNB would not impact this recommendation unless the rate of nodal metastasis were significantly higher.