Thyroid dysfunction due to immune checkpoint inhibitors: American Society of Clinical Oncology guideline
| Situation | Action |
|---|---|
| Screening | Thyroid function tests, ie, thyroid-stimulating hormone (TSH) with or without thyroxine (T4) every 4–6 weeks while on therapy |
| Asymptomatic hypothyroidism (grade 1), TSH > 4.5 and < 10 mIU/L | Monitor thyroid function tests routinely as above Continue immune checkpoint inhibitor |
| Symptomatic hypothyroidism (grade 2) or TSH persistently > 10 mIU/L | Start levothyroxine (1.6 μg/kg/day if age < 70; 25–50 μg/day if age > 70 or multiple comorbidities); monitor TSH every 6–8 weeks until TSH is at goal, then every 6–12 months unless symptoms change Consider holding immune checkpoint inhibitor until symptoms resolve Consider endocrine consultation for challenging presentation or for hormonal therapy |
| Severely symptomatic hypothyroidism (grade 3 or 4) | Hold immune checkpoint inhibitor until symptoms resolve Hospital admission usually required Endocrine consultation recommended to assist with rapid hormone replacement Hydrocortisone should be given in the event central hypothyroidism is considered Start on chronic levothyroxine therapy and monitor as above on discharge. |
| Asymptomatic or mildly symptomatic thyrotoxicosis (grade 1) | Continue immune checkpoint inhibitor Start beta-blocker Monitor TSH and T4 every 2–3 weeks after diagnosis for possible hypothyroidism transition (and treat as for primary hypothyroidism) Consider endocrine consult for persistent thyrotoxicosis (> 6 weeks) |
| Mildly symptomatic thyrotoxicosis (grade 2) | Consider holding immune checkpoint inhibitor until symptoms improve Consider endocrine consultation Start on beta-blockers Refer to endocrinologist for persistent thyrotoxicosis (> 6 weeks) for additional workup and possible medical thyroid suppression |
| Severely symptomatic thyrotoxicosis (grade 3 or 4) | Hold immune checkpoint inhibitor until symptoms resolve Endocrine consult for all patients Start on beta-blocker Hospitalization with endocrine consultation to be considered in severe cases to guide medical therapy |
Adapted from reference 49.