Adrenal metastasis occurs when cancer cells from a primary tumor spread to one or both adrenal glands. Located on top of each kidney, these glands produce several important hormones. The spread of cancer to the adrenal glands signifies an advanced stage of the disease. This condition is different from primary adrenal cancer, which originates within the adrenal gland tissue itself.
Adrenal metastases are the most common malignant tumors found in the adrenal glands, second only to benign growths. Their discovery has become more frequent with the routine use of advanced imaging for cancer staging and monitoring. The presence of a metastasis indicates the original cancer has traveled through the bloodstream or lymphatic system to establish a new tumor.
Primary Cancer Sources and Associated Symptoms
The adrenal glands are a frequent site for metastasis due to their rich blood supply. Cancers that most commonly spread to the adrenal glands include:
- Lung cancer
- Breast cancer
- Kidney cancer (renal cell carcinoma)
- Melanoma
- Lymphoma
The median time from an initial cancer diagnosis to the discovery of adrenal metastases is approximately 2.5 years.
Adrenal metastasis is often asymptomatic, meaning it does not produce noticeable symptoms in most cases. Consequently, these secondary tumors are frequently identified incidentally during imaging scans, such as CT or PET scans, performed to monitor the primary cancer. When symptoms do arise, it is from the tumor growing large enough to press on surrounding tissues, which can lead to pain in the back, flank, or a feeling of fullness in the abdomen.
In rare instances, if cancer destroys more than 90% of both adrenal glands, it can cause adrenal insufficiency. Symptoms of this uncommon condition include:
- Fatigue
- Weight loss
- Nausea
- Abdominal pain
Diagnosis and Evaluation
Confirming adrenal metastasis involves imaging techniques and, in some cases, a tissue sample. Imaging is the primary method used to detect and evaluate a mass in the adrenal gland. Computed tomography (CT) scans are the initial imaging test, while magnetic resonance imaging (MRI) can provide more detailed images to help distinguish between benign and malignant tumors. A positron emission tomography (PET) scan is useful for detecting cancer throughout the body and can confirm if an adrenal mass is metabolically active, a common feature of cancerous tissue.
While imaging provides strong evidence, a biopsy is the definitive method to confirm a diagnosis of adrenal metastasis. During this procedure, a small sample of tissue is removed from the adrenal mass, typically using a needle guided by a CT scan. A pathologist then examines the cells to identify the specific type of cancer and confirm that the cells match those of the primary tumor.
Treatment Approaches
The management of adrenal metastasis is dictated by the state of the primary cancer, as its presence signifies that the disease has spread systemically. Therefore, treatment is focused on the entire body. Systemic therapies like chemotherapy, immunotherapy, or targeted therapy are the primary approach, aiming to control the cancer throughout the body.
Local therapies, which target the adrenal metastasis directly, are considered in specific situations. Surgery to remove the adrenal gland (adrenalectomy) may be an option if the adrenal metastasis is the only site of cancer spread or if it is causing severe symptoms. Complete surgical removal in cases of isolated adrenal metastasis offers a potential for cure.
Another local treatment is radiation therapy, which uses high-energy rays to destroy cancer cells. A precise form called Stereotactic Body Radiation Therapy (SBRT) can deliver focused radiation to the tumor while minimizing damage to surrounding tissue. If a metastasis is small, not causing symptoms, and appears slow-growing, a doctor may recommend active surveillance, where the tumor is monitored with regular scans.
Prognosis and Management of Adrenal Function
The prognosis for an individual with adrenal metastasis is most closely tied to the type and stage of the primary cancer, as well as the extent of spread to other organs. The presence of an adrenal metastasis is one factor among many that determine the overall outlook. Advances in systemic treatments and local therapies are continuously improving outcomes for patients with advanced-stage cancers.
A consideration in managing adrenal metastasis is the potential impact on the gland’s function after treatment. If only one adrenal gland is removed or damaged, the remaining gland can compensate and produce sufficient hormones. If both adrenal glands are removed or significantly damaged by treatment, it results in adrenal insufficiency. This means the body can no longer produce essential corticosteroid hormones, such as cortisol.
This condition requires lifelong hormone replacement therapy. Patients take daily medication to replace these hormones, which effectively manages the insufficiency.