**5. Surgery as the Solution?**

Thyroid surgery is becoming increasingly expensive. A large population-based study demonstrated increasing patient charges for both inpatient and outpatient elective thyroid surgery, with increasing costs of £644 or 4.31% every year between 2006 and 2014, after controlling for multiple clinical and demographic variables and adjusting for inflation [43]. There is ample evidence that a thyroid lobectomy presents no survival difference compared to a total thyroidectomy in low-risk PTC less than four centimetres in diameter [44]. Hemithyroidectomy has the advantage of retaining natural thyroid function in 80% or more of patients and avoids permanent hypoparathyroidism and its sequelae. The disadvantages of a hemithyroidectomy are the reduction of efficacy of thyroglobulin as a tumour marker, the preclusion of radioiodine as adjuvant treatment, and a higher risk of requiring a second operation for local recurrence. Overall, the 2015 American Thyroid Association guidelines conclude that a lobectomy is an acceptable treatment primarily to avoid the morbidity of total thyroidectomy documented in lower volume practices [3] rather than because it is a better option from an oncological point of view.

Most thyroid surgery in the US and many parts of the world is performed by lowvolume general, ENT, and, to a lesser extent, maxillofacial surgeons [45]. Whilst a hemithyroidectomy in low-risk thyroid cancer may offer lower morbidity with unchanged cancer efficacy [46] the cost considerations appear to have taken a back seat. The Quality Adjusted Life Year (QALY) can be used in the assessment of the value of medical interventions [47]. If the Incremental Cost-Effectiveness Ratio (ICER) is applied to the treatment of a solitary thyroid nodule with an FNA biopsy that is 'suspicious for cancer' a hemithyroidectomy alone does not appear to be the most cost-effective and appears to be inferior in cost-effectiveness compared to a total thyroidectomy. This calculation is based on a model that includes the

accuracy of a frozen section and the rate of injury to the recurrent laryngeal nerve (RLN). Unfortunately, the study failed to factor in the varying rate of malignancy for an FNA biopsy and calculated just 12 months of the life-long hormonal replacement, long-term permanent nerve palsy, and permanent hypocalcaemia. Equally a thorough costing of ultrasound surveillance of the neck was also insufficiently assessed but is likely to add additional cost to the hemithyroidectomy group [42]. As the study was published before the 2015 ATA guidelines, the higher rate of completion thyroidectomy might have altered the cost-effectiveness analysis.

A more recent cost-effectiveness analysis compared total thyroidectomy versus lobectomy for small (2 cm) nodules suspicious for PTC (defined as Bethesda V) [48]. The authors conclude that a total thyroidectomy protocol produced an incremental cost of £1929 and incremental effectiveness of minus 0.24 QALY as compared to the lobectomy protocol. The consecutive sensitivity analysis demonstrated that total thyroidectomy apparently only becomes a cost-effective strategy if the risk of stages III and IV PTC is 82.4% among patients with Bethesda V cytology on preoperative FNA. These counterintuitive findings may be related to the quantification of the risk of morbidity (hypothyroidism, hypoparathyroidism, or unilateral RLN injury) after lobectomy was estimated at up to 50% which is high compared to national registry data [49]. Whether the true cost of follow-up and additional imaging rather than a cheaper nurse led thyroglobulin follow-up have been contemplated was not clearly stated. One feature that is not quantified adequately is the cost of lifelong physician follow-up and frequent office ultrasound in the lobectomy group that is likely to make the surveillance of anything less than a total thyroidectomy more expensive.
