Adrenal cancer is one of the rarest cancers in humans, with only 0.5 to 2 cases diagnosed per million people each year. To put that in perspective, in the United States that translates to roughly 200 to 600 new cases annually. The formal name for this cancer is adrenocortical carcinoma (ACC), and it originates in the outer layer of the adrenal glands, the small hormone-producing organs that sit on top of each kidney.
How the Numbers Compare
For context, breast cancer affects roughly 1,300 people per million each year, and even pancreatic cancer, often considered uncommon, strikes about 130 per million. Adrenal cancer’s incidence of 0.5 to 2 per million makes it roughly 100 to 1,000 times less common than these better-known cancers. It is rare enough that many oncologists will go an entire career without treating a case, which can make diagnosis and treatment more challenging for patients who do develop it.
Who Gets Adrenal Cancer
ACC follows a distinctive two-peak pattern. It appears most often in children younger than 5 and in adults between 40 and 60. The childhood peak is especially pronounced in southern Brazil, where pediatric adrenal cancer occurs at roughly 15 times the rate seen in the United States. That regional spike is driven by an inherited mutation in the TP53 gene, the same gene involved in Li-Fraumeni syndrome, a hereditary condition that raises the risk of multiple cancers. About 2.4% of people carrying a specific Brazilian founder variant of this mutation develop childhood adrenal cancer.
Outside of that genetic cluster, most cases appear sporadically in middle-aged adults with no family history of the disease.
How Adrenal Cancer Is Found
Adrenal tumors are actually discovered by accident more often than you might expect. Between 1.4% and 7.3% of abdominal CT scans reveal an incidental adrenal mass, and that number climbs to about 10% in older patients. The vast majority of these “incidentalomas” are benign. Still, the discovery of an adrenal mass is often the first step toward diagnosing the rare malignant cases, since nonfunctional adrenal cancers may not produce symptoms until they grow large enough to press on surrounding organs or spread.
Functional vs. Nonfunctional Tumors
One important distinction in adrenal cancer is whether the tumor produces excess hormones. In children, the overwhelming majority of adrenal cancers are functional, with 85% or more producing abnormal amounts of hormones like cortisol, androgens, or aldosterone. These hormone surges can cause noticeable changes: rapid weight gain, early puberty in children, new facial hair growth in women, high blood pressure, or muscle weakness.
In adults, the picture flips. Roughly 65% to 85% of adult adrenal cancers are nonfunctional, meaning they don’t produce detectable hormone excess. That’s a problem, because without hormonal symptoms to serve as an early warning, nonfunctional tumors tend to be caught later, often when they’ve already grown large or spread.
Staging and What It Means for Prognosis
Adrenal cancer is staged using a system developed by the European Network for the Study of Adrenal Tumors (ENSAT). The stages reflect tumor size, whether it has invaded nearby tissue, and whether it has spread to lymph nodes or distant organs.
- Stage I: Tumor is 5 cm or smaller, confined to the adrenal gland, with no spread.
- Stage II: Tumor is larger than 5 cm but still confined, with no spread.
- Stage III: Tumor has grown into surrounding tissue or reached nearby lymph nodes.
- Stage IV: Cancer has spread to distant parts of the body.
Survival rates drop sharply with advancing stage. Patients diagnosed at Stage I or II, when the tumor can be completely removed surgically, have significantly better outcomes than those diagnosed at Stage III or IV. Because the disease is so rare, survival statistics come from relatively small patient groups, but the pattern is consistent: early detection matters enormously.
How Adrenal Cancer Is Treated
Surgery to completely remove the tumor is the cornerstone of treatment and the only realistic path to a cure. When surgeons can achieve a complete resection, the outlook improves substantially. One clinical trial found that patients who had complete tumor removal followed by additional drug therapy had a five-year recurrence-free survival rate of about 75%.
After surgery, some patients receive a medication that specifically targets adrenal tissue to reduce the risk of the cancer coming back. This drug has been shown to significantly improve recurrence-free survival compared to observation alone, though its side effects can be significant and require close monitoring. For advanced or metastatic disease, chemotherapy combinations are used, but response rates are generally lower.
Because adrenal cancer is so uncommon, treatment is best handled at specialized centers with experience in the disease. Pathologists use a scoring system called the Weiss system, which evaluates nine microscopic features of the tumor tissue, to confirm whether an adrenal mass is truly malignant. A score of 3 or higher out of 9 indicates cancer. Getting this pathology right is critical, and it’s another reason specialized centers matter.
Why Rarity Makes This Cancer Harder
The extreme rarity of adrenal cancer creates a cascade of challenges. Most primary care doctors and even many oncologists have limited experience recognizing it. Clinical trials are smaller and slower to enroll, which means treatment advances come more gradually than for common cancers. Patients often face delays in diagnosis, particularly when their tumor is nonfunctional and discovered only after it has grown or spread.
If you’ve been told you have an adrenal mass or are being evaluated for possible adrenal cancer, seeking care at a center that regularly treats endocrine tumors can make a meaningful difference in both the accuracy of your diagnosis and the quality of your treatment plan.