Cost-Effectiveness Analysis of Elective Neck Dissection in Patients With Clinically Node-Negative Oral Cavity Cancer

Abstract

Purpose Recently, a large randomized trial found a survival advantage among patients who received elective neck dissection in conjunction with primary surgery for clinically node-negative oral cavity cancer compared with those receiving primary surgery alone. However, elective neck dissection comes with greater upfront cost and patient morbidity. We present a cost-effectiveness analysis of elective neck dissection for the initial surgical management of early-stage oral cavity cancer. Methods We constructed a Markov model to simulate primary, adjuvant, and salvage therapy; disease recurrence; and survival in patients with T1/T2 clinically node-negative oral cavity squamous cell carcinoma. Transition probabilities were derived from clinical trial data; costs (in 2015 US dollars) and health utilities were estimated from the literature. Incremental cost-effectiveness ratios, expressed as dollar per quality-adjusted life-year (QALY), were calculated with incremental cost-effectiveness ratios less than $100,000/QALY considered cost effective. We conducted one-way and probabilistic sensitivity analyses to examine model uncertainty. Results Our base-case model found that over a lifetime the addition of elective neck dissection to primary surgery reduced overall costs by $6,000 and improved effectiveness by 0.42 QALYs compared with primary surgery alone. The decrease in overall cost despite the added neck dissection was a result of less use of salvage therapy. On one-way sensitivity analysis, the model was most sensitive to assumptions about disease recurrence, survival, and the health utility reduction from a neck dissection. Probabilistic sensitivity analysis found that treatment with elective neck dissection was cost effective 76% of the time at a willingness-to-pay threshold of $100,000/QALY. Conclusion Our study found that the addition of elective neck dissection reduces costs and improves health outcomes, making this a cost-effective treatment strategy for patients with early-stage oral cavity cancer.

Fig 1.

State transition diagram. The four main health states are represented by ovals. Patients may transition from “No evidence of disease” to “Salvaged,” “Multiply recurrent or metastatic,” or “Death.” Patients may receive adjuvant therapies after their initial surgery, including radiation with or without chemotherapy. Patients with local or regional recurrence may receive salvage surgery and radiation with or without chemotherapy. Patients with multiply recurrent or metastatic disease receive palliative chemotherapy.

Fig 2.

Cost-effectiveness model validation results. The top panel (table) shows how our model predicts disease recurrence and overall survival compared with the D’Cruz randomized trial. The bottom panel (plot) shows how our model predicts survival compared with the D’Cruz randomized trial. END, elective neck dissection; WW, watchful waiting.

Fig 3.

One-way sensitivity analyses. The graphic shows the impact of varying individual model inputs on the cost effectiveness of elective neck dissection (END) compared with watchful waiting for early-stage oral cavity cancer. The individual plots represent (A) the impact of varying the hazard ratio for survival between END and watchful waiting, (B) the impact of varying the health utility deduction for a neck dissection, (C) the risk of recurrence for END, and (D) watchful waiting. A treatment strategy dominates another if it was less costly and more effective. A strategy was considered cost effective if the incremental cost-effectiveness ratio was under $100,000 per quality-adjusted life year.

Fig 4.

Probabilistic sensitivity analysis scatter plot. This plot shows the distribution of incremental costs and incremental effectiveness of individual iterations of the probabilistic sensitivity analysis comparing the cost effectiveness of elective neck dissection (END) versus watchful waiting in early-stage oral cavity cancer. The dashed line represents a willingness-to-pay threshold of $100,000 per quality-adjusted life year (QALY). Blue and red dots represent individual iterations of the probabilistic sensitivity analysis; blue dots indicate iterations in which END was considered cost effective, and red dots indicate iterations in which END was not cost effective compared with watchful waiting.

Fig A1.

Cost-effectiveness acceptability curve. This plot represents the results of a probabilistic sensitivity analysis (for details, see Methods) comparing the cost-effectiveness of elective neck dissection (END) versus watchful waiting (WW) in early-stage oral cavity cancer. QALY, quality-adjusted life year.