Adrenal Metastases

What the adrenal glands do

The two adrenal glands sit on top of the kidneys. Their outer layer (cortex) makes cortisol, which helps the body handle stress and maintain blood pressure and blood sugar, and aldosterone, which controls salt and water balance. The inner layer (medulla) makes adrenaline. The adrenals have a rich blood supply, which is one reason cancers spread there easily.

Which cancers spread to the adrenal glands

Symptoms

Most adrenal metastases cause no symptoms. When symptoms occur, they come from:

• Size: a dull ache in the back, flank or upper abdomen.
• Bleeding into the tumor: sudden severe pain.
• Destruction of both glands: adrenal insufficiency develops only when more than about 90% of both glands is destroyed. Signs include fatigue, weakness, nausea, abdominal pain, weight loss, low blood pressure, salt craving and darker skin. An adrenal crisis is an emergency.

Symptoms from the original cancer, such as cough, weight loss and fatigue, are usually more prominent.

Diagnosis

Imaging

• CT scan: adrenal metastases are usually larger than 4 cm, irregular, and have a higher density than benign adenomas. Benign adrenal adenomas are common, contain fat, look low-density on non-contrast CT, and wash out contrast quickly.
• PET-CT: metastases usually take up the tracer strongly; benign adenomas usually do not.
• MRI: chemical shift imaging helps identify fat-containing benign adenomas.

Hormone tests

Before any biopsy or surgery on an adrenal mass, doctors check for a hormone-producing tumor, especially pheochromocytoma (with blood or urine metanephrines), because a biopsy of a pheochromocytoma can trigger a dangerous blood pressure crisis. Cortisol tests check for both excess and deficiency.

Biopsy

A CT-guided needle biopsy confirms the diagnosis when it would change treatment, for example when an adrenal mass is the only possible site of spread.

Adrenal function

People with metastases in both glands should have a morning cortisol test or ACTH stimulation test to check for adrenal insufficiency.

Treatment

Treatment depends on the primary cancer, how widely it has spread, and overall health.

• Systemic therapy: chemotherapy, immunotherapy, targeted drugs or hormone therapy treat cancer throughout the body, including the adrenal deposits.
• Adrenalectomy: surgical removal of the adrenal gland, often by keyhole (laparoscopic) surgery, for an isolated adrenal metastasis when the primary cancer is controlled. This can give long-term disease control in selected patients, especially with lung or kidney cancer.
• Stereotactic body radiation therapy (SBRT): highly focused radiation in a few sessions, an alternative to surgery.
• Thermal ablation: destroys the tumor with heat or cold through a needle, for selected small lesions.
• Hormone replacement: hydrocortisone and fludrocortisone for adrenal insufficiency, with sick-day rules and an emergency injection kit.

Outlook

Outlook mainly depends on the type and extent of the primary cancer. Adrenal metastases usually indicate stage 4 (metastatic) disease. However, people with an isolated adrenal metastasis, a so-called oligometastasis, sometimes achieve long-term survival with surgery or SBRT plus systemic therapy. Newer immunotherapies and targeted drugs have improved outcomes in lung cancer and melanoma.

Frequently asked questions

What are the symptoms of adrenal metastases?

Most cause no symptoms and are found on scans. Large tumors can cause back, flank or abdominal pain. If both adrenal glands are extensively involved, adrenal insufficiency can cause fatigue, nausea, weight loss, dizziness and salt craving.

Does an adrenal mass in someone with cancer always mean metastasis?

No. Benign adrenal adenomas are common, found in a few percent of adults on CT. In people with cancer, imaging features, PET results, size, growth over time and sometimes biopsy are used to tell a benign adenoma from a metastasis.

Can adrenal metastases be cured?

In selected people with a single adrenal metastasis and a controlled primary cancer, surgery or stereotactic radiation can provide long-term control and occasionally cure. For most people, adrenal metastases are part of widespread cancer, and treatment focuses on controlling the disease.

What is the prognosis for lung cancer that has spread to the adrenal gland?

It is generally considered stage 4 lung cancer. Prognosis varies widely with the cancer type, its genetic features, the number of metastases and response to treatment. Isolated adrenal spread treated aggressively and modern immunotherapy and targeted therapies have improved survival for some patients.