Is intraoperative touch imprint cytology of sentinel lymph nodes in patients with breast cancer cost effective?
BACKGROUND: Sentinel lymph nodes (SLNs) are generally evaluated postoperatively, requiring 5-7 days for assessment. SLNs can also be evaluated intraoperatively by using touch imprint cytology (TIC), thus providing the surgeon immediate feedback and allowing for concurrent completion node dissection (CND) for positive SLNs. The authors hypothesized that TIC, when compared with standard postoperative SLN assessment alone, would permit a cost-effective evaluation of SLNs in patients with clinically node-negative breast cancer. METHODS: A decision-analysis model was created to compare TIC with standard postoperative SLN assessment alone. Sensitivity and specificity of TIC were determined prospectively from 342 patients who underwent SLN biopsy assessed by both techniques. Short-term health states associated with surgical staging were defined, and utilities were estimated using EuroQol-5D. Base-case analysis was performed to estimate quality-adjusted life years and the incremental cost-effectiveness ratio. Sensitivity analyses were performed to examine stability of model parameters. RESULTS: For each tumor stage, TIC was cost effective, and for patients with larger tumors (T3 and T4), TIC was the dominant strategy. The analysis was robust to changes in sensitivity and specificity of TIC, prevalence of metastasis, probability of complications, and cost. However, when utility associated with standard SLN assessment was 0.9 or greater, this became the preferred strategy. CONCLUSIONS: TIC is cost effective for assessing SLN metastasis intraoperatively. For patients with larger tumors, it is not only more effective, but also less costly than standard SLN assessment alone. TIC may be particularly useful for patients who experience significant anxiety while awaiting results of standard SLN assessment.