Ensuring Quality in Thyroid Cancer Surgery

US Endocrinology, 2017;13(1):22–6 DOI: https://doi.org/10.17925/USE.2017.13.01.22

Abstract:

Thyroid cancer incidence is increasing worldwide. Though long-term survival rates are excellent, recurrence remains a significant problem, which highlights potential areas of needed improvement, including the surgical care of these patients. This review paper identifies tools and markers that can be used to improve surgical quality in thyroid cancer. Preoperative surgical planning starts with an adequate ultrasound evaluation of the cervical lymph node basins. Postoperatively, thyroglobulin and radioactive iodine uptake scans can track adequacy of resection. In addition, lymph node yield and lymph node ratios serve as indirect markers for assessing the quality of lymph node dissections. Current research also suggests that high-volume surgeons have improved oncological outcomes. Surgeons can use these tools and information to follow and potentially improve the care provided to patients.
Keywords: Thyroid cancer, surgical quality, ultrasound, thyroglobulin, nodal dissection
Disclosure:

Disclosure: Maria F Bates, Kristin L Long, and Rebecca S Sippel have nothing to declare in relation to this article. No funding was received in the publication of this article. This study involves a review of the literature and did not involve any studies with human or animal subjects performed by any of the authors.

Authorship: All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship of this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval to the version to be published.

Received: February 21, 2017 Accepted April 24, 2017
Correspondence: Maria F Bates, Department of Surgery, 600 Highland Avenue, K4/739 CSC, Madison, WI 53792, US. E: batesm@surgery.wisc.edu
Open Access: This article is published under the Creative Commons Attribution Noncommercial License, which permits any noncommercial use, distribution, adaptation, and reproduction provided the original author(s) and source are given appropriate credit.

Thyroid carcinoma is one of the most common solid tumors worldwide. The incidence of thyroid cancer is increasing, with an estimated 57,000 newly diagnosed cases in the US in 2017. Approximately three-quarters of these patients are female, with the majority being between 20 and 34 years of age. Though five-year survival rates are greater than 98% overall, the disease still inflicts significant morbidity on those affected.1 At present, surgery represents the mainstay for treatment and the only option for a definitive cure. Performing the appropriate operation for thyroid carcinoma is the first step towards achieving optimal outcomes. Current quality markers in thyroid surgery are predominately based on morbidity from often transient complications, such as temporary hypoparathyroidism or recurrent laryngeal nerve palsy. In order to improve the surgical care of patients with thyroid cancer, it is important that we focus not just on safety, but also on oncologic outcomes. Given the time delay to disease recurrence, surgeons are often not aware that disease recurrence has been identified or that the recurrence may have been due to inadequate initial surgical management. In a recent retrospective view of our institutional data, we collected all patients that underwent re-operative surgery for differentiated thyroid cancer. We found that the majority of patients had abnormal radiographic and/or elevated thyroglobulin (Tg) levels at their 6 month postoperative follow up from their initial surgery. Only three patients out of 92 actually had a negative ultrasound and undetectable Tg within 1 year, defining them as truly recurrent disease. By this definition, the remaining patients really just underwent a re-operation for persistent disease, which suggests a need for improved surgical quality. In order to improve the quality of thyroid cancer surgery, we need to identify short-term markers that can be used to give feedback to surgeons to allow them to improve their surgical care. In this review, we focus on the importance on quality surgery for thyroid cancer, specifically on the initial pre-operative evaluation, surgeon volume and outcomes, adequacy of surgical resection, and nodal disease. It is our hope that surgeons who perform surgery for thyroid cancer will use this information not only to track their own clinical outcomes but also to use these tools to re-evaluate the quality of care given to their patients.

Quality surgery starts with a good pre-operative evaluation
In order to achieve curative surgery as well as optimizing the effects of postoperative treatment and facilitate follow-up, surgeons must eradicate all the disease from the neck at the initial operation. Pre-operative radiographic imaging is the first step towards optimizing these outcomes. The neck ultrasound has emerged as the recommended first-line imaging modality to evaluate, not only disease within the thyroid gland, but also any potential spread to the central or lateral nodal basins in the neck. The most recent American Thyroid Association (ATA) guidelines recommend a formal pre-operative neck ultrasound evaluation of nodal disease prior to undergoing any thyroid surgery.2,3 This is further supported by Kocharyan and colleagues who demonstrated that lymph node disease identified on pre-operative ultrasound accurately corresponds to postoperative lymph node pathology.4

Pre-operative ultrasound evaluation primarily determines the extent of surgery performed and assists in determining prognosis. The quality of ultrasound exams of the neck is very operator-dependent and there is significant variability in interpretation of this modality. One recent study focused on the implementation of pre-operative ultrasound evaluation of lymph node disease in patients with well-differentiated thyroid carcinoma. This study demonstrated that high-quality cervical ultrasound changed the operative approach in 23% of patients, where a majority underwent more extensive operations for otherwise clinically occult lymph node metastases.5 Unfortunately, not all ultrasounds are equal and significant variability exists between non-specialist performed neck ultrasounds and specialist-performed neck ultrasounds. Mazzaglia evaluated 261 patients treated by a single surgeon for management of their thyroid disease over a two-year period, all of whom had an outside neck ultrasound available for comparison. Surgeon performed ultrasound (SPUS) was conducted on all patients by one surgeon, and 18% of the cohort had a change in treatment plans due to ultrasound discrepancies between the outside ultrasound and the SPUS. In eight of 132 patients undergoing thyroidectomy, the operative plan was significantly altered based on the results of the SPUS.6 Similar studies have also noted the superiority of the surgeon-performed ultrasound.7

At our institution, we compared outcomes for thyroid cancer patients with pre-operative ultrasounds performed by a thyroid specialist versus a non-specialist. We demonstrated that a thyroid specialist was much more likely to document lymph status (69 versus 20%).8 In addition, patients with a pre-operative ultrasound performed by a specialist had lower uptake on postoperative radioactive iodine scans and lower recurrence rates compared to those who had an ultrasound performed by a nonspecialist. In those patients with a pre-operative ultrasound performed by a non-specialist, a significant number of recurrences arose less than 12 months after their initial surgery. These early recurrences are likely secondary to inadequate initial surgery due to poor pre-operative recognition of the extent of disease.8 These findings prompted radiologists to re-evaluate their techniques and create a standardized approach to neck ultrasound for thyroid cancer that incorporates the ATA guidelines as well as focuses specific attention to the pertinent questions for endocrine surgeons.9 In summary, any patient undergoing thyroid surgery should have a thorough evaluation of the cervical lymph node basins prior to surgery. In addition, it is important to consider the experience of the proceduralist performing the ultrasound and his or her familiarity with cervical neck ultrasound for thyroid carcinoma.

Abnormal lymph node features on ultrasound include larger size, loss of fatty hilum, round rather than oval shape, hyper-echogenicity, cystic changes, micro-calcifications, and peripheral vascularity. Of these variables, studies have demonstrated that peripheral vascularity and micro-calcifications show the highest sensitivity and specificity for detecting metastatic disease.10,11 Once identified by ultrasound or physical exam, abnormal lymph nodes in the lateral neck should undergo cytological confirmation with fine needle aspiration (FNA) in order to determine the extent of dissection needed. When cytology is inadequate or ultrasound and cytology findings are discordant, Tg washout testing can be done to confirm the presence of metastatic disease.12,13 Pre-operative FNA is not always necessary to evaluate central neck lymph nodes. These nodes can be difficult to access with FNA when the thyroid is in situ and can be easily assessed during the thyroid operation. It is best to perform a central lymph node dissection concomitant to thyroid surgery as the procedures utilize the same incision. Therefore, if there are concerning findings on pre-operative ultrasound within the central neck, a central neck dissection during the initial operation best serves the patient.

References:
1. American Cancer Society, Cancer Facts & Figures, Atlanta: American Cancer Society, 2017.
2. Haugen BR, Alexander EK, Bible KC, et al., 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer, Thyroid, 2016;26:1–133.
3. Yeh MW, Bauer AJ, Bernet VA, et al., American Thyroid Association statement on preoperative imaging for thyroid cancer surgery, Thyroid, 2015;25:3–14.
4. Kocharyan D, Schwenter F, Belair M, Nassif E, The relevance of preoperative ultrasound cervical mapping in patients with thyroid cancer, Can J Surg, 2016;59:113–7.
5. O'Connell K, Yen TW, Quiroz F, et al., The utility of routine preoperative cervical ultrasonography in patients undergoing thyroidectomy for differentiated thyroid cancer, Surgery, 2013;154:697–701; discussion -3.
6. Mazzaglia PJ, Surgeon-performed ultrasound in patients referred for thyroid disease improves patient care by minimizing performance of unnecessary procedures and optimizing surgical treatment, World J Surg, 2010;34:1164–70.
7. Carneiro-Pla D, Amin S, Comparison between preconsultation ultrasonography and office surgeon-performed ultrasound in patients with thyroid cancer, World J Surg, 2014;38:622–7.
8. Oltmann SC, Schneider DF, Chen H, Sippel RS, All thyroid ultrasound evaluations are not equal: sonographers specialized in thyroid cancer correctly label clinical N0 disease in well differentiated thyroid cancer, Ann Surg Oncol, 2015;22:422–8.
9. Kumbhar SS, O'Malley RB, Robinson TJ, et al., Why Thyroid Surgeons Are Frustrated with Radiologists: Lessons Learned from Pre- and Postoperative US, Radiographics, 2016;36:2141–53.
10. Leboulleux S, Girard E, Rose M, et al., Ultrasound criteria of malignancy for cervical lymph nodes in patients followed up for differentiated thyroid cancer, J Clin Endocrinol Metab, 2007;92:3590–4.
11. Liu Z, Zeng W, Liu C, et al., Diagnostic accuracy of ultrasonographic features for lymph node metastasis in papillary thyroid microcarcinoma: a single-center retrospective study, World J Surg Oncol, 2017;15:32.
12. Snozek CL, Chambers EP, Reading CC, et al., Serum thyroglobulin, high-resolution ultrasound, and lymph node thyroglobulin in diagnosis of differentiated thyroid carcinoma nodal metastases, J Clin Endocrinol Metab, 2007;92:4278–81.
13. Grani G, Fumarola A, Thyroglobulin in lymph node fine-needle aspiration washout: a systematic review and meta-analysis of diagnostic accuracy, J Clin Endocrinol Metab, 2014;99:1970–82.
14. Al-Hilli Z, Strajina V, McKenzie TJ, et al., The role of lateral neck ultrasound in detecting single or multiple lymph nodes in papillary thyroid cancer, Am J Surg, 2016;212:1147–53.
15. Park JH, Lee YS, Kim BW, et al., Skip lateral neck node metastases in papillary thyroid carcinoma, World J Surg, 2012;36:743–7.
16. Wu G, Fraser S, Pai SI, et al., Determining the extent of lateral neck dissection necessary to establish regional disease control and avoid reoperation after previous total thyroidectomy and radioactive iodine for papillary thyroid cancer, Head Neck, 2012;34:1418–21.
17. Kandil E, Noureldine SI, Abbas A, Tufano RP, The impact of surgical volume on patient outcomes following thyroid surgery, Surgery, 2013;154:1346–52; discussion 52–3.
18. Meltzer C, Klau M, Gurushanthaiah D, et al., Surgeon volume in thyroid surgery: Surgical efficiency, outcomes, and utilization, The Laryngoscope, 2016;126:2630–9.
19. Nouraei SA, Virk JS, Middleton SE, et al., A national analysis of trends, outcomes and volume-outcome relationships in thyroid surgery, Clin Otolaryngol, 2017;42:354–65.
20. Sosa JA, Bowman HM, Tielsch JM, et al., The importance of surgeon experience for clinical and economic outcomes from thyroidectomy, Ann Surg, 1998;228:320–30.
21. Adam MA, Thomas S, Youngwirth L, et al., Is there a mnimum number of thyroidectomies a surgeon should perform to optimize patient outcomes?, Ann Surg, 2017;265:402–7.
22. Al-Qurayshi Z, Robins R, Hauch A, et al., Association of surgeon volume with outcomes and cost savings following thyroidectomy: A national forecast, JAMA Otolaryngol Head Neck Surg, 2016;142:32–9.
23. Adkisson CD, Howell GM, McCoy KL, et al., Surgeon volume and adequacy of thyroidectomy for differentiated thyroid cancer, Surgery, 2014;156:1453–59; discussion 60.
24. Bilimoria KY, Bentrem DJ, Ko CY, et al., Extent of surgery affects survival for papillary thyroid cancer, Ann Surg, 2007;246:375–81; discussion 81–4.
25. Schneider DF, Ojomo KA, Chen H, Sippel RS, Remnant uptake as a postoperative oncologic quality indicator, Thyroid, 2013;23:1269–76. 26. Kashat L, Orlov S, Orlov D, et al., Serial post-surgical stimulated and unstimulated highly sensitive thyroglobulin measurements in low- and intermediate-risk papillary thyroid carcinoma patients not receiving radioactive iodine, Endocrine, 2016;54:460–6.
27. Janovsky CC, Maciel RM, Camacho CP, et al., A prospective study showing an excellent response of patients with low-risk differentiated thyroid cancer who did not undergo radioiodine remnant ablation after total thyroidectomy, Eur Thyroid J, 2016;5:44–9.
28. Lee HS, Roh JL, Gong G, et al., Risk factors for re-recurrence after first reoperative surgery for locoregional recurrent/persistent papillary thyroid carcinoma, World J Surg, 2015;39:1943–50.
29. Rosario PW, Mourao GF, Calsolari MR, Can the follow-up of patients with papillary thyroid carcinoma of low and intermediate risk and excellent response to initial therapy be simplified using second-generation thyroglobulin assays?, Clin Endocrinol (Oxf), 2016;85:596–601.
30. Choudhary C, Wartofsky L, Tefera E, Burman KD, Evaluation of thyroid bed nodules on ultrasonography after total thyroidectomy: Risk for loco-regional recurrence of thyroid cancer, Eur Thyroid J, 2015;4:106–14.
31. Lee SG, Lee J, Kim MJ, et al., Long-term oncologic outcome of robotic versus open total thyroidectomy in PTC: a case-matched retrospective study, Surg Endosc, 2016;30:3474–9.
32. Schneider DF, Chen H, Sippel RS, Impact of lymph node ratio on survival in papillary thyroid cancer, Ann Surg Oncol, 2013;20:1906–11.
33. Schneider DF, Mazeh H, Chen H, Sippel RS, Lymph node ratio predicts recurrence in papillary thyroid cancer, The Oncologist, 2013;18:157–62.
34. Lee SG, Ho J, Choi JB, et al., Optimal cut-off values of lymph node ratio predicting recurrence in papillary thyroid cancer, Medicine, 2016;95:e2692.
35. Heaton CM, Chang JL, Orloff LA, Prognostic implications of lymph node yield in central and lateral neck dissections for well-differentiated papillary thyroid carcinoma, Thyroid, 2016;26:434–40.
36. Vas Nunes JH, Clark JR, Gao K, et al., Prognostic implications of lymph node yield and lymph node ratio in papillary thyroid carcinoma, Thyroid, 2013;23:811–6.
37. Randolph GW, Duh QY, Heller KS, et al., The prognostic significance of nodal metastases from papillary thyroid carcinoma can be stratified based on the size and number of metastatic lymph nodes, as well as the presence of extranodal extension, Thyroid, 2012;22:1144–52.
Keywords: Thyroid cancer, surgical quality, ultrasound, thyroglobulin, nodal dissection