Thyroid cancer: Addressing your concerns

1. Thyroid cancer:Addressing your concerns Alice Y.Y. Cheng, MD, FRCPC March 24, 2007

2. Question 1 Thyroid cancer is the most rapidly increasing cancer among Canadians age 20-44. True False

3. Question 2 One is considered “cured” after being disease-free for 10 years and no further follow-up is required. True False

4. Outline • What types? • How common? • Treat? • Follow-up?

5. 2006 American Thyroid Association Guidelines

6. What is the thyroid?

7. Thyroid – where is it? • Gland at the front of the neck • Shaped like a butterfly • Location and size of a bowtie

9. Thyroid – what does it do? • It is a factory • Makes thyroid hormone (T4, T3) • Thyroid hormone affects every function in the body

10. Thyroid – what controls it? • Feedback system (thermostat) • Pituitary  TSH (thyroid stimulating hormone) • If too much T4/T3, then less TSH or vice versa

12. What can go wrong? • Functional • Hyperthyroidism • Hypothyroidism • Structural • Nodules • Cancer • Both

13. Thyroid Cancer

14. Thyroid Cancer • Differentiated • Papillary (83%) • Follicular (9%) • Medullary (2%) • Anaplastic • Lymphoma “Cancer Care Ontario: Cancer in Young Adults in Canada, May 2006

15. How common? • ~3400 cases in Canada in 2006 • 3rd most common in young adults • Most rapidly growing • 2-3 times more prevalent in women “Cancer Care Ontario: Cancer in Young Adults in Canada, May 2006

16. “Cancer Care Ontario: Cancer in Young Adults in Canada, May 2006

17. Prognosis = good! • Age at diagnosis (<45 yrs) • Tumour size • Recurrence • Metastases • Pathologic features

18. Cumulative Recurrenceand Cancer Death After Initial Therapy 40 Recurrence At 30 years: Recurrence 30% Cancer death 8% 30 Cumulative percent 20 Cancer death 10 0 0 10 20 30 40 Years after initial therapy Patients at risk (n) 10 1075 568 185 1355 Mazzaferri. Am J Med. 1994; 97:418–428.

19. Therefore … • Thyroid cancer is common – particularly in young adults • Prognosis is generally good • Death from thyroid cancer is uncommon • Recurrence can happen even years after diagnosis

20. Treatment

21. Treatment • TOTAL THYROIDECTOMY • To remove the cancer and the rest of the thyroid • To provide information about the cancer (size etc)

22. Treatment • RADIOIODINE REMNANT ABLATION • Iodine is taken up by thyroid cells • Radioiodine in large dose will destroy any remaining thyroid cells (normal and cancer) • Works better when cells are “hungry” for iodine

23. Treatment • RADIOIODINE REMNANT ABLATION • Low iodine diet 2 weeks prior • Must have TSH > 35 • Withdrawal or Thyrogen • Whole body scan 1 week later

24. Treatment 3.THYROID REPLACEMENT (Thyroxine) • To replace missing thyroid hormone • Give a little “extra” to push down TSH to not stimulate any remaining cells • Empty stomach, away from other meds

25. Treatment 3.THYROID REPLACEMENT • TSH < 0.1 in high risk cases • TSH 0.1-0.5 other cases • May consider TSH 0.3 – 2 long term in some cases

26. Long-term surveillance • Absolutely CRITICAL and LIFE-LONG • Clinical exam • Neck ultrasound PLUS …

27. Surveillance • THYROGLOBULIN (“tumour marker”) • Only made by thyroid cells • Should be LOW because thyroid cells should be all gone • “Stimulated” vs “Suppressed”

28. Tg on suppression • Tg measurement while on thyroxine (TSH low) • Useful if high = recurrence • Low is not reassuring • Misses 23% of recurrence / mets • Kloos et al. JCEM 2005;90:5047-57

29. Stimulated Tg • Withdrawal or Thyrogen • TSH > 35 • Significantly increases sensitivity • Should be done 6-12 months after initial treatment

30. Withdrawal protocol • Stop T4 replacement 6 weeks prior • Take T3 from weeks 1-4 • Stop T3 at least 2 weeks prior • Develop hypothyroid symptoms • Resume replacement after procedure • Recovery can take 2-3 weeks

32. Thyrogen • Injection on 2 consecutive days • Avoid need for hypothyroid symptoms • $1600 for the 2 doses • Covered by 3rd party insurers and ODB • Can continue thyroid medications

33. Thyrogen Protocol

34. Thyroglobulin • Stimulated Tg < 2 ug/L  good • Stimulated Tg 2-5 ug/L –> recheck 6m • Stimulated Tg > 5 ug/L = recurrence • Freq of subsequent testing depends

35. Surveillance • Surveillance must be life long! • Recurrences can occur LATE! • Monitor • Clinical exam • Ultrasounds • Thyroglobulin on suppression • Periodic stimulated thyroglobulins

36. Take home points … • Thyroid cancer is common and growing • Prognosis excellent but recurrence rate is high – lifelong surveillance • Thyroidectomy, suppression, remnant ablation, surveillance with Tg & U/S • Withdrawal versus Thyrogen

37. Question 1 Thyroid cancer is the most rapidly increasing cancer among Canadians age 20-44. True False

38. Question 2 One is considered “cured” after being disease-free for 10 years and no further follow-up is required. True False

39. Thank you for your attention! Questions?

40. Thyroid Exam

41. Two approaches … • Anterior • Posterior

42. Thyroid exam • Landmark with your fingers • Locate the isthmus • Do NOT take your fingers off the patient • The only things connected to the isthmus are the lobes!

43. Thyroid exam • Comment on • Size (# times normal) • Texture (normal, firm, hard) • Symmetry • Nodular or smooth • Mobility • Tenderness