Ectopic ACTH Syndrome: When Tumor Resection Fails to Achieve Remission
Surgical localization and resection of the ectopic ACTH-secreting tumor is the initial management strategy. When remission is not achieved — or when the tumor is occult or metastatic and curative resection is not feasible — a structured next-line protocol applies.
Prior Treatment & Failure Condition
The preceding intervention was localizing and resecting the ectopic ACTH-secreting tumor with node dissection as appropriate. Remission was defined as morning serum cortisol <5 µg/dL (<138 nmol/L) or urine free cortisol <28–56 nmol/d (<10–20 µg/d) within 7 days of selective tumor resection. Failure to reach these targets — or inability to achieve resection — triggers escalation to the protocol described here.
Next-Line Approach (Partial Overview)
Management in this setting centres on medical therapy with steroidogenesis inhibitors as the primary modality, with surgical and targeted treatment options available in selected clinical circumstances.
Full regimen details, agent selection, sequencing, and dose-titration targets are in the complete protocol.
Treatment Goals
The clinical aim is eucortisolism — normalization of urine free cortisol, with specific serum cortisol benchmarks guiding dose adjustments when certain agents are used.
References
DOI: 10.1210/jc.2015-1818- We recommend steroidogenesis inhibitors under the following conditions: as second-line treatment after TSS in patients with CD, either with or without RT/radiosurgery; as primary treatment of EAS in patients with occult or metastatic EAS; and as adjunctive treatment to reduce cortisol levels in ACC.
- We suggest bilateral adrenalectomy for occult or metastatic EAS or as a life-preserving emergency treatment in patients with very severe ACTH-dependent disease who cannot be promptly controlled by medical therapy.
- We suggest targeted therapies to treat ectopic ACTH syndrome.
- Several case reports show that octreotide, a potent SST2 agonist, may control ACTH and cortisol secretion for a short- to midterm period in patients with recurrent or unresectable ectopic ACTH-secreting tumors.
- In three reports, the tyrosine kinase inhibitors vandetanib and sorafenib rapidly and fully controlled hypercortisolism caused by ACTH secretion from metastatic medullary thyroid carcinomas.
- The goal is clinical normalization using cortisol levels as a proxy end-point (except for mifepristone, see below).
- With no cross-reactivity issues, the treatment target is either UFC in the normal range or mean serum cortisol levels that are between 5.4 and 10.8 µg/dL (150–300 nmol/L) throughout the day.