Critical appraisal of RAI low grade thyroid cancer

Critical appraisal of RAI in low grade Thyroid cancer

1. Critical Appraisal

2. Disclosure None

3. Critical Appraisal Mr Viresh Arora ENT Consultant Mr M Y Mian ENT Consultant & Lead

4. Objectives RCT In patients with low risk DTC, who have undergone thyroidectomy “ Assess whether non inclusion of post op RAI is non-inferior to admin of RAI with respect to % of patients without an event at 3 years” Perspective In low risk DTC undergoing thyroidectomy post-op RAI controversial in absence of demonstrated benefits Retrospective studies not shown benefit of postop RAI Absence prospective studies -argue favour RAI in low risk thyroid cance r

5. Study design ESTIMABL2 Trial

6. Primary end point Role of Radioactive iodine (I131)in thyroid cancer after thyroidectomy

7. Methods RAI 0.9 mg ® thy -2 consecutive days > 24 hour 30 mci RI admin > 2-5 days WBS + SPECT neck Follow up measurement TG + TG ab’s @10 mths , yrly USG neck patients 10 mths / 3 yr’s Non RAI (- )TG ab’s elevated TG:- 5 ng / ml during TH treatment or > 2 ng / ml during TH treatment on 2 cons. measurement 6 mths apart

8. Events Primary Structural event : USG neck suspicious LN/ thyroid mass Biological event : thyroglobulin > 5ng / ml Functional :positive uptake on RAI Secondary Q uality of life Anxiety / fear of recurrence D ysfunction of lacrimal and salivary glands

9. Results

10. Conclusion P atients undergoing thyroidectomy for low risk DTC follow up alone without RAI was non-inferior to RAI in terms events @ 3 years

11. Critical analysis Methodology Positives Clearly defined protocol B aseline characteristics (age , sex, histology, staging neck dissection) set out Study groups similar & completed study Similar level intervention until conclusion - follow up interval Results positives Results of intervention comprehensive, (CI) reported Power calculation 95%. Outcomes clearly specified No differential drop out between the study groups One sided hypothesis test @ 0.05, p-value reported

12. Study limitations Not mentioned? -Randomization of participants in each study group - Assignment of participants to i ntervention level -Separate group analysis - Harms or unintended effects Limitations! Relative and Absolute effects? missing/ incomplete data Groups not segregated according to ND (40% ) Neither participants nor the investigators were blinded Non RAI-functional events not included Events for TG -different cut offs for different groups

13. Study limitations.. Bias’s Secondary outcomes No stats comparison Salivary & lacrimal symptoms questionnaires - not validated

14. Appraisal summary Research question ! Whether post operative RAI can be avoided in low risk thyroid cancer is focused -population studied - intervention given -comparator chosen - outcomes measured Post operative RAI is non-inferior in low risk thyroid cancer Study addresses a clear focussed research question Study designed to assess the outcome of intervention Topic relevant to current practice Truly represents the article

15. Overall Useful study Demonstrated may be able to avoid post op RAI in low risk DTC May be less applicable to UK population ?T2/T3 staging Would this study change our current practice ?

16. Thank you