1. Management of Thyroid Incidentalomas Department of Surgery Ruttonjee & TSK Hospitals Dr YC Lui

2. Department of Surgery, Ruttonjee & TSK Hospitals 2 Introduction Incidentaloma refers to unexpected, asymptomatic tumour discovered during unrelated procedure Incidentaloma refers to unexpected, asymptomatic tumour discovered during unrelated procedure Important subject in endocrinology and surgery, warrants attention of physician and resources of medical system Important subject in endocrinology and surgery, warrants attention of physician and resources of medical system Mirilas P et al. Am Surg 2002

3. Department of Surgery, Ruttonjee & TSK Hospitals 3 Introduction Most thyroid nodules are benign Most thyroid nodules are benign Need systematic approach to reassure patients with nodules less likely to be malignant while ensuring all malignant incidentalomas detected Need systematic approach to reassure patients with nodules less likely to be malignant while ensuring all malignant incidentalomas detected

4. Department of Surgery, Ruttonjee & TSK Hospitals 4 Reliability of Clinical Examination Most thyroid nodules 1cm or larger can be palpated especially favorably situated Most thyroid nodules 1cm or larger can be palpated especially favorably situated Nodule located deep within or on posterior surface of gland, in patient with short, fat neck is more difficult to palpated Nodule located deep within or on posterior surface of gland, in patient with short, fat neck is more difficult to palpated

5. Department of Surgery, Ruttonjee & TSK Hospitals 5 Reliability of Clinical Examination 50% of nodules discovered on USG escaped detection on clinical examination, 30% of nodules not detected by palpation were larger than 2 cm 50% of nodules discovered on USG escaped detection on clinical examination, 30% of nodules not detected by palpation were larger than 2 cm Sensitivity of palpation of thyroid gland in terms of size and nodularity was 38% Sensitivity of palpation of thyroid gland in terms of size and nodularity was 38% Christensen SB et al. Ann Chir Gynaecol 1985 Brander A et al. J Clin Ultrasound 1992

6. Department of Surgery, Ruttonjee & TSK Hospitals 6 Prevalence Thyroid nodules are common Thyroid nodules are common Palpable thyroid nodules in 4 to 10 % of USA population Palpable thyroid nodules in 4 to 10 % of USA population Female has significantly higher prevalence then males ( 6.4% vs. 1.6%) Female has significantly higher prevalence then males ( 6.4% vs. 1.6%) Vander JB et al. Ann Intern Med 1997

7. Department of Surgery, Ruttonjee & TSK Hospitals 7 Autopsy Data About 50% of postmortem of patients with no known thyroid disease revealed thyroid nodules About 50% of postmortem of patients with no known thyroid disease revealed thyroid nodules Study of young men in military aged 18-39 revealed thyroid nodules in 13% Study of young men in military aged 18-39 revealed thyroid nodules in 13% Mortensen J et al. J Clin Endocrinol 1955 Oertel J et al. Med Ann Dist Columbia 1965

8. Department of Surgery, Ruttonjee & TSK Hospitals 8 Risk for Malignancy of Incidentalomas Thyroid carcinoma encompass less than 1% of all cancers Thyroid carcinoma encompass less than 1% of all cancers 2 to 4 new cases of clinically significant cancer per 100,000 population in USA each year 2 to 4 new cases of clinically significant cancer per 100,000 population in USA each year Incidence rate of thyroid cancer in HK in 1998- 1999 was 2.5 per 100,000 for men and 6.5 per 100,000 for women respectively Incidence rate of thyroid cancer in HK in 1998- 1999 was 2.5 per 100,000 for men and 6.5 per 100,000 for women respectively Weiss RE et al. Curr Opin Oncol 2002 Rober JS et al. Surg Clin N Am 2004 Hong Kong Cancer Registry 2000

9. Department of Surgery, Ruttonjee & TSK Hospitals 9 Risk for Malignancy of Incidentalomas Risk of development of thyroid cancer Exposure to ionizing radiation Exposure to ionizing radiation Family history of thyroid cancer or MEN Family history of thyroid cancer or MEN Environmental exposure to toxins (e.g. Hexachlorobenzene, tetrachlorodibenzo-p- dioxin, volcanic lava) Environmental exposure to toxins (e.g. Hexachlorobenzene, tetrachlorodibenzo-p- dioxin, volcanic lava) Nodule in patient younger than 20 years or older than 50 years Nodule in patient younger than 20 years or older than 50 years Roman SA et al. Curr Opin Oncol 2003

10. Department of Surgery, Ruttonjee & TSK Hospitals 10 Risk for Malignancy of Incidentalomas Ito Y et al. Current Cancer Therapy Reviews 2005

11. Department of Surgery, Ruttonjee & TSK Hospitals 11 Clinical Behavior of PMC Most occult carcinoma were papillary carcinoma Most occult carcinoma were papillary carcinoma Indolent course and excellent prognosis Indolent course and excellent prognosis Rate of distant metastasis and mortality was 6.8% and 1.4% in a Chinese population in Taiwan Rate of distant metastasis and mortality was 6.8% and 1.4% in a Chinese population in Taiwan Fukunaga FH et al. Cancer 1975 Lin JD et al. Am J Clin Oncol 1996

12. Department of Surgery, Ruttonjee & TSK Hospitals 12 Clinical Behavior of PMC Ito Y et al. Current Cancer Therapy Reviews 2005

13. Department of Surgery, Ruttonjee & TSK Hospitals 13 Detection of Thyroid Incidentalomas Ultrasound Thyroid incidentalomas commonly detected in radiographic imaging of head and neck for other reasons Thyroid incidentalomas commonly detected in radiographic imaging of head and neck for other reasons USG is inexpensive, sensitive, allows high resolution imaging of thyroid USG is inexpensive, sensitive, allows high resolution imaging of thyroid Can detect nodule as small as 3 mm Can detect nodule as small as 3 mm Simeone JF et al.AJR Am J Roentgenol 1987

14. Department of Surgery, Ruttonjee & TSK Hospitals 14 Detection of Thyroid Incidentalomas Characteristic of thyroid nodules on ultrasound that suggest malignancy Microcalcification in center of nodule Microcalcification in center of nodule Irregular or blurred margins Irregular or blurred margins Marked hypoechogenicity Marked hypoechogenicity Intranodular vascular pattern Intranodular vascular pattern Incomplete peripheral halo Incomplete peripheral halo Kim KW et al. AJR Am J Roentgenol 2002, Papini E et al. J Clin Endocrinol Metab 2002

15. Department of Surgery, Ruttonjee & TSK Hospitals 15 Detection of Thyroid Incidentalomas Table 3 Comparison of Sonographic and Histologic Findings SonographicClassification Histologic Findings MalignantBenignTotal MalignantBenign46336708273 Total49106155 Sensitivity - 93.8% Specificity - 66% PPV-56.1% NPV-95.9% Kim KW et al. AJR Am J Roentgenol 2002

16. Department of Surgery, Ruttonjee & TSK Hospitals 16 Detection of Thyroid Incidentalomas Table 4 Diagnostic Index for individual Sonographic Criteria of Malignant Thyroid Nodules Sonographic Characteristics Sensitivity (%) Specificity (%) PPV (%) NPV (%) Accuracy (%) Microcalcification Irregular or microlobulated margin Marked hypoechogenicity More tall than wide 59.255.126.532.785.88394.392.570.76068.466.779.88073.574.877.474.272.973.5 Most malignant nodules had multiple sonographic findings suggestive of malignancy ( mean no. of suspicious findings per malignant nodules, 2.6) Accuracy of each sign was 72.9-77.4%, sensitivity was low 26.5-59.1% Kim KW et al. AJR Am J Roentgenol 2002

17. Department of Surgery, Ruttonjee & TSK Hospitals 17 USG Findings

18. Department of Surgery, Ruttonjee & TSK Hospitals 18 USG Findings

19. Department of Surgery, Ruttonjee & TSK Hospitals 19 Detection of Thyroid Incidentalomas CT or MRI Thyroid nodules commonly detected incidentally during CT or MRI of head and neck, and chest Thyroid nodules commonly detected incidentally during CT or MRI of head and neck, and chest Malignancy cannot be defined base on CT or MRI characteristics unless invasion into adjacent structures Malignancy cannot be defined base on CT or MRI characteristics unless invasion into adjacent structures Silver RJ et al. Surg Clin N Am 2004

20. Department of Surgery, Ruttonjee & TSK Hospitals 20 Detection of Thyroid Incidentalomas Nuclear medicine studies Thyroid nodule detected in 2-3% of PET or PET/CT Thyroid nodule detected in 2-3% of PET or PET/CT Around 50% of PET detected thyroid nodules were malignant at cytology or thyroidectomy Around 50% of PET detected thyroid nodules were malignant at cytology or thyroidectomy Kang KW et al. J Clin Endocrinol Metab 2002 Cohen MS et al. Surgery 2001 Kim TY et al. Laryngoscope 2005

21. Department of Surgery, Ruttonjee & TSK Hospitals 21 Thyroid incidentaloma detected during radiological imaging Focused history and Physical examination Thyroid Cancer Risk Factor Evaluation - history of radiation- hoarseness or dysphagia - Personal or family history endocrine ca- adenopathy - Male gender- thyroid function tests Patient with life expectancy < 1y Defer evaluation unless patient symptomatic or hyperthyroid Patient with life expectancy > 1 y Ultrasound exam and documentation of: Number and size of nodules Worrisome ultrasound features Nodules between 8-15 mm with 1 or more worrisome USG features Nodules > 15 mm Nodules < 8 mm - Consider FNA -Risk factor/ life expectancy profile -Patient counseling to report any change -Reevaluation with USG in 6 mo FNA with USG guidance Benign FNA Indeterminate or Suspicious or Diagnostic for Malignancy FNA Insufficient Cellularity FNA -Patient counseling to report any change -Reevaluation with USG in 1-2 yr Refer to Surgeon Repeat FNA within 3 months Silver RJ et al. Surg Clin N Am 2004

22. Department of Surgery, Ruttonjee & TSK Hospitals 22 Management of Thyroid Microcarcinoma Lobectomy may preserve thyroid function, reduce incidence of hypoparathyroidism and recurrent laryngeal nerve injury Lobectomy may preserve thyroid function, reduce incidence of hypoparathyroidism and recurrent laryngeal nerve injury Approximately 50% of patients will require thyroxine replacement Approximately 50% of patients will require thyroxine replacement Farkas EA et al. Am Surg 2002

23. Department of Surgery, Ruttonjee & TSK Hospitals 23 Management of Thyroid Microcarcinoma Some authors suggested lobectomy for single microcarcinoma restricted to thyroid Some authors suggested lobectomy for single microcarcinoma restricted to thyroid Total thyroidectomy for multicentric tumour or with LN metastasis Total thyroidectomy for multicentric tumour or with LN metastasis Baudin E et al. Cancer 1998 Rosario PW et al. Arq Bras Endocrinol Metobol 2004

24. Department of Surgery, Ruttonjee & TSK Hospitals 24 Management of Thyroid Microcarcinoma Papillary carcinoma frequently multifocal, high incidence of local metastatic lesion at diagnosis Papillary carcinoma frequently multifocal, high incidence of local metastatic lesion at diagnosis Rate of permanent hypoparathyroidism and recurrent laryngeal nerve injury very low in experience hands Rate of permanent hypoparathyroidism and recurrent laryngeal nerve injury very low in experience hands Total or near-total thyroidectomy often recommended Total or near-total thyroidectomy often recommended Ito Y et al. Thyroid 2003, Chow SM et al. Cancer 2003, Pellegriti G et al. J Clin Endocrinol Metab 2004 Baudi E et al. Cancer 1998, Hay ID et al. Surgery 1992, Pellegriti G et al. J Clin Endocrinol Metab 2004

25. Department of Surgery, Ruttonjee & TSK Hospitals 25 Management of Thyroid Microcarcinoma Others studies argue aggressive surgery is not warranted Others studies argue aggressive surgery is not warranted Based on high frequency of incidental papillary microcarcinoma detected in autopsy specimens, the authors assumed most PMC do not required immediate surgical treatment Based on high frequency of incidental papillary microcarcinoma detected in autopsy specimens, the authors assumed most PMC do not required immediate surgical treatment Ito Y et al. Thyroid 2003 Ito Y et al. Current Cancer Therapy Reviews 2005

26. Department of Surgery, Ruttonjee & TSK Hospitals 26 Management of Thyroid Microcarcinoma 751 patients diagnosed as PMC by USG and FNAC between 1993 and 2002 751 patients diagnosed as PMC by USG and FNAC between 1993 and 2002 Surgical treatment recommended for 67 patients with unfavourable features Surgical treatment recommended for 67 patients with unfavourable features 211 preferred observation without immediate surgical treatment 211 preferred observation without immediate surgical treatment Tumour size in more than 70% of patients decreased or did not change at each follow up period Tumour size in more than 70% of patients decreased or did not change at each follow up period Ito Y et al. Thyroid 2003 Ito Y et al. Current Cancer Therapy Reviews 2005

27. Department of Surgery, Ruttonjee & TSK Hospitals 27 Management of Thyroid Microcarcinoma 19 patients had tumour size >10mm 19 patients had tumour size >10mm 2 patients developed LN metastasis in lateral compartment 2 patients developed LN metastasis in lateral compartment Observation can be initial therapeutic strategy for asymptomatic PMC Observation can be initial therapeutic strategy for asymptomatic PMC Ito Y et al. Thyroid 2003 Ito Y et al. Current Cancer Therapy Reviews 2005

28. Department of Surgery, Ruttonjee & TSK Hospitals 28 Conclusions Small incidentally detected thyroid nodules increase as imaging advance Small incidentally detected thyroid nodules increase as imaging advance Historical and autopsy data point to generally excellence prognosis of small thyroid malignancies Historical and autopsy data point to generally excellence prognosis of small thyroid malignancies Optimal surgical treatment is still controversial Optimal surgical treatment is still controversial More randomized controlled studies on incidentally detected thyroid nodules needed More randomized controlled studies on incidentally detected thyroid nodules needed