Management of Lung Cancer Patient with Established Adrenal Insufficiency on Pembrolizumab, Carboplatin, and Pemetrexed
Ensure the patient is on stable corticosteroid replacement therapy before initiating chemotherapy, and increase to stress-dose steroids during treatment cycles to prevent adrenal crisis.
Critical Pre-Treatment Requirements
Corticosteroid Management
- Confirm adequate baseline replacement therapy with either prednisone 5-10 mg daily or hydrocortisone 10-20 mg in the morning and 5-10 mg in early afternoon before starting cancer treatment 1
- Administer stress-dose corticosteroids during each chemotherapy cycle: increase to 2-3 times maintenance dose (prednisone 20 mg daily or hydrocortisone 20-30 mg morning, 10-20 mg afternoon) on treatment days 1
- Add fludrocortisone 0.1 mg daily if the patient has primary adrenal insufficiency (high ACTH, low cortisol) for mineralocorticoid replacement 1
- Do NOT rely solely on the dexamethasone premedication required for pemetrexed (4 mg twice daily for 3 days around each cycle) as adequate replacement—this is for rash prevention, not adrenal support 2
Mandatory Pemetrexed Premedications
- Initiate folic acid 400-1000 mcg orally daily starting 7 days before first pemetrexed dose and continue until 21 days after the last dose 2
- Administer vitamin B12 1 mg intramuscularly 1 week prior to first pemetrexed dose and every 3 cycles thereafter (do not substitute oral B12) 2
- Give dexamethasone 4 mg orally twice daily for 3 consecutive days (day before, day of, and day after each pemetrexed administration) 2
Monitoring Protocol
Baseline and Pre-Cycle Assessments
- Check morning cortisol and ACTH levels before each cycle to detect worsening adrenal function, as pembrolizumab can cause secondary adrenal insufficiency even in patients with pre-existing disease 3, 4, 5
- Obtain complete blood count on Days 1,8, and 15 of each cycle 2
- Assess creatinine clearance (Cockcroft-Gault) before each cycle—do not administer pemetrexed if CrCl <45 mL/min 2
- Monitor serum sodium and potassium closely, as hyponatremia and hyperkalemia indicate inadequate replacement or worsening adrenal insufficiency 1
Signs of Adrenal Crisis During Treatment
Watch for sudden onset of:
- Severe fatigue, weakness, anorexia, nausea, or vomiting 3, 4, 5, 6
- Hypotension unresponsive to fluids 7
- Hyponatremia (<130 mEq/L) or hypoglycemia 5, 8
- These symptoms can develop rapidly even after multiple cycles (reported after 8-41 cycles of pembrolizumab) 3, 5
Management of Adrenal Crisis
Emergency Treatment
- Immediately administer IV hydrocortisone 100 mg or dexamethasone 4 mg if diagnosis uncertain 1
- Give at least 2 L normal saline for volume resuscitation 1
- Hold pembrolizumab until patient is stabilized on replacement hormone 1
- Taper stress-dose corticosteroids down to maintenance over 7-14 days after discharge 1
Special Considerations
Pembrolizumab-Induced Adrenal Insufficiency Risk
- Pembrolizumab can cause isolated ACTH deficiency (secondary adrenal insufficiency) as an immune-related adverse event, with incidence of 0.98-1.3% 5, 7, 9
- Onset is variable: can occur after 4 months to over 14 months of treatment 3, 4, 6
- Patients with pre-existing adrenal insufficiency may be more susceptible to allergic reactions during pembrolizumab therapy 3
- Progression of hypopituitarism can occur even after pembrolizumab discontinuation 8
NSAID Precautions with Pemetrexed
- Avoid ibuprofen for 2 days before, day of, and 2 days after pemetrexed if CrCl is 45-79 mL/min 2
- Monitor more frequently for myelosuppression, renal, and gastrointestinal toxicity if NSAID use cannot be avoided 2