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Adrenal Metastasis and Surgery

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An adrenal metastasis is a cancer which has spread from some other organ (another primary site) to one or both adrenal glands. When appropriate, adrenal surgery in this scenario can save and prolong life.

Since primary adrenal cancer is rare, an adrenal metastasis is the most common malignant lesion of the adrenal gland.  Nearly any cancer can spread to the adrenal glands via blood vessels, but some tumors are more likely than others to metastasize to this organ.

Adrenal metastasis can occur from cancers in the lung (~40%), breast (~35%), melanoma, gastrointestinal tract, pancreas, and kidney among other places. The cancers that most frequently spread to the adrenal gland(s) are:

  • Lung cancer (Primarily non-small cell lung cancer, NSLC)
  • Breast cancer
  • Melanoma
  • Colon & Rectal cancer
  • Stomach cancer (Gastric carcinoma)
  • Pancreas
  • Kidney cancer (Renal cell carcinoma, RCC)
  • Esophageal cancer
  • Liver cancer (Hepatocellular carcinoma, HCC)
  • Lymphoma

Figure 1. An adrenal metastasis (arrow) from a lung cancer, removed by Dr. Carling

Adrenal Metastasis and Surgery

Adrenal Metastasis Incidence

An adrenal metastasis has traditionally been identified on autopsy. For example, in one study, the incidence of adrenal metastases from renal cell carcinoma was up to 30% in an autopsy series, but from clinical diagnosis, it was less frequent, about 10%. However, with the increasing role of imaging scans (CT, MRI, and PET) in diagnosing, staging, and follow-up of malignancies, along with X-rays/scans for other reasons (belly pain in the emergency room), an adrenal metastasis can 1st be identified as an incidentaloma. With the increased imaging detection of breast and lung cancers, adrenal metastasis detection has also increased.

About half of incidentally discovered adrenal masses in patients with a history of cancer, or a recently diagnosed extra-adrenal malignancy, are an adrenal metastasis. The average time from cancer diagnosis to the identification of an adrenal metastasis is roughly 2.5 years; however, metastasis to the adrenal gland has been reported up to two decades after initial treatment of the primary tumor. Also, it is uncommon for an adrenal metastasis to occur before identification of the primary malignancy.

Adrenal Metastasis Presentation

Most occurrences of an adrenal metastasis will not exhibit symptoms (90-95%).  Occasionally, due to large tumor size or rapid growth, the adrenal metastasis may have localized symptoms like back/flank or abdominal pain due to tumor mass effect or bleeding into the tumor. Rarely, adrenal insufficiency will be a presenting symptom (if a significant portion of the bilateral adrenal glands are affected, typically >90%). Addison’s disease, or adrenal insufficiency, can present with anorexia, weight loss, nausea, vomiting, abdominal pain, weakness, fatigue, lethargy, fever, confusion, or electrolyte imbalances.

Adrenal Metastasis Imaging

As mentioned, an adrenal metastasis is typically detected incidentally on a scan (CT, MRI, or PET) performed before or during treatment for the underlying cancer. Based on current studies, no single imaging modality can be considered the gold standard for the comprehensive evaluation of adrenal incidentalomas or to distinguish malignant from benign adrenal masses. CT and MRI assess lipid content to differentiate benign (high lipid content) from potentially malignant (low lipid content) adrenal masses and are mainly used to identify benign lesions and exclude adrenal malignancy. The growth of an adrenal lesion over short-term imaging follow-up (i.e., repeat CT, or MRI, in six months), looking for predictors of primary adrenal malignancy and adrenal metastasis (local invasion, irregular borders, and central necrosis), can be helpful in diagnosis and determining tumor aggression. PET is mainly used for detection of malignant disease. Although not a specific marker for cancer, PET has a high sensitivity and specificity in differentiating adrenal masses as benign or malignant in those with known primary cancers.

Figure 2. CT scan demonstrating an adrenal metastasis from renal cell carcinoma (RCC, kidney) to the right adrenal gland (arrow). This tumor was removed using the Mini Back Scope Adrenalectomy (MBSA), which is the best adrenal operation. An adrenal metastasis (arrow) from a lung cancer, removed by Dr. Carling

Adrenal Metastasis: To Biopsy, or Not to Biopsy?

If you have a scan suspicious for an adrenal metastasis, you do not necessarily need any further evaluation, especially if you have spread to other organs. In some cases, your doctor may wish to be certain that a mass in your adrenal gland is due to metastatic cancer and recommend a CT-guided biopsy. CT-guided fine-needle aspiration (FNA) may be useful when imaging is equivocal (adrenal mass has not been conclusively characterized as benign), the lesion is hormonally inactive, and most importantly, the management of the patient would possibly be altered with information from the biopsy. This is one scenario when performing biopsy of an adrenal gland is appropriate. It is of utmost importance that pheochromocytoma is excluded with biochemical testing (plasma or urinary metanephrines) before the biopsy to avoid the potential risk of hypertensive crisis and life-threatening complications. Although FNA cannot necessarily differentiate between benign adenoma and adrenocortical carcinoma, FNA is very useful in confirming the presence of metastatic disease in adrenal lesions. However, FNA is an invasive procedure, with the potential for complications, and thus, before having an adrenal metastasis biopsy, it is ALWAYS best to have your expert surgeon determine if it is necessary. 

Adrenal Metastasis Treatment

Having a cancer that has spread to the adrenal gland(s), means that the cancer is advanced, Stage 4. However, if there is no other evidence of spread, the only potential cure is complete surgical removal of the adrenal metastasis. Fortunately, an adrenal metastasis has a much better long-term survival prognosis compared to metastases to other organ sites, namely liver, lung, or bone. Further, adrenalectomy in selected patients (with isolated disease or one/few areas of spread from primary sites including lung, melanoma, colon, and kidney) can result in prolonged and improved survival compared with similar patients who do not undergo adrenalectomy.

Figure 3. CT scan demonstrating a left adrenal metastasis from colon cancer (arrow). Dr. Carling performed a partial adrenalectomy using the Mini Back Scope Adrenalectomy (MBSA), since the patient already had the right adrenal gland removed.

Not all adrenal metastases should be surgically removed. In fact, in most cases, removing an adrenal metastasis is not helpful due to cancer spread elsewhere. In such a scenario, systemic treatment with chemotherapy, targeted therapies, immunotherapy, and/or radiation therapy is better. Some people also participate in clinical trials studying new drugs and procedures. However, if you or your loved one has a solitary (single) adrenal metastasis, then complete surgical removal of the disease is the only potential cure.

The decision to proceed with adrenalectomy for metastatic cancer requires thoughtful consideration of the natural history of the underlying cancer, tumor biology, presence of disease outside the adrenal (if any), patient performance status, and availability of alternative treatments. These alternative treatments include radiation (Stereotactic body radiotherapy; SBRT) and ablation (Image-guided percutaneous ablation), both of which are not as effective as surgical removal. However, these techniques may be beneficial in those who are not good candidates for surgery or would not otherwise tolerate an adrenal operation. The decision on how best to proceed is again ideally guided by your expert surgeon.

Absence of local invasion into surrounding structures and a disease-free interval greater than six months from the original cancer diagnosis are considered good prognostic factors when proceeding with adrenalectomy for the metastasis. Results vary depending on the cancer site of origin. Minimally invasive laparoscopic adrenalectomy (Mini Back Scope Adrenalectomy, MBSA) is as effective as open adrenalectomy for adrenal metastasis with proven reduction in postoperative pain, morbidity, and length of hospital stay and quicker return to preoperative activities. Adrenal masses (typically less than 6-8 cm in size) without local invasion are ideal for the best approach to adrenalectomy, MBSA, particularly when having to treat bilateral disease (no repositioning necessary).

Bottom-line, if you or a loved one have an adrenal metastasis, it is best to consult with an expert surgeon to determine best course of action.  For the right individuals, surgery can be minimally invasive and curative. 

Additional Resources: 

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Author

Dr. Andrew Rhodes, DO, FACS

Dr Drew Rhodes was the Director of the Endocrine Center at HCA North Carolina and the University of North Carolina for 4 years until being recruited to joing the "Dream Team" in Tampa several years ago. He received his formal training in endocrine surgery at Yale University where he worked closely with Dr Carling who says "Drew is the best of the best and wherever I go, I want Drew at my side. He is one of the best surgeons I have ever met." After spending a week with Dr Norman, he agrees: "Few surgeons have the hands that Drew has and after I saw him operate I knew we had to have him on our team." Dr Rhodes received his general surgery training at Penn prior to fellowship training at Yale. He had a decorated military career spending 5 years as a surgeon at Walter Reed Medical Center in Washington, DC. Drew is married and has an 10 year old boy and a 6 year old girl.