From the Research
Cortisol levels should be checked before starting immunotherapy, then at regular intervals during treatment, typically every 3-4 months, and whenever symptoms of adrenal insufficiency appear, with more frequent monitoring necessary for patients on immune checkpoint inhibitors, especially during the first 12 weeks of treatment 1.
Importance of Monitoring
The monitoring of cortisol levels is crucial in patients undergoing immunotherapy due to the risk of immune-related adverse events, including adrenal insufficiency. Adrenal insufficiency can be life-threatening if not detected early, and its symptoms can be non-specific, making regular monitoring essential 2, 3.
Recommended Monitoring Schedule
The recommended monitoring schedule includes checking cortisol levels before starting immunotherapy, then at regular intervals during treatment. For patients on immune checkpoint inhibitors like pembrolizumab, nivolumab, ipilimumab, or atezolizumab, more frequent monitoring may be necessary, especially during the first 12 weeks of treatment when the risk of immune-related adverse events is highest 4, 5.
Key Considerations
- Morning cortisol levels (drawn between 7-9 AM) are preferred for accuracy.
- If morning cortisol is below 5 μg/dL (138 nmol/L), an ACTH stimulation test should be performed to confirm adrenal insufficiency.
- Patients should be educated about symptoms of adrenal insufficiency, including fatigue, weakness, anorexia, nausea, vomiting, abdominal pain, hypotension, and electrolyte abnormalities.
- The mechanism involves T-cell mediated inflammation of the pituitary or adrenal glands, disrupting the hypothalamic-pituitary-adrenal axis and cortisol production 1.
Clinical Implications
Regular monitoring of cortisol levels and prompt recognition of adrenal insufficiency are critical to prevent life-threatening complications. Healthcare professionals should remain vigilant in monitoring laboratory progression in these patients, and early recognition of the phase of hypercortisolism and its likely rapid transformation into secondary adrenal insufficiency can facilitate timely hormonal replacement and prevent complications 3, 1.