Understanding adenoid cystic carcinoma: Symptoms, treatment and outlook

Adenoid cystic carcinoma is a rare cancer of the secretory glands, which are glandular tissues that make and release substances such as saliva, tears and sweat. It can develop throughout your body, but it is most common in the salivary glands in your head and neck.

Here, I’ll share more about adenoid cystic carcinoma, including symptoms, prognosis and the research we’re doing to advance treatment.

How rare is adenoid cystic carcinoma?

Adenoid cystic carcinoma accounts for about 1% of all head and neck cancers. It is the most common tumor of the minor salivary glands and the second most common tumor of the major salivary glands.

What causes adenoid cystic carcinoma?

We’re not sure what causes adenoid cystic carcinoma. There are no known risk factors.

The median age of people diagnosed with adenoid cystic carcinoma is 50. It is slightly more common in women.

What are the symptoms of adenoid cystic carcinoma?

Adenoid cystic carcinoma typically grows very slowly. So, it may take years for symptoms to appear.

Your symptoms will depend on where the cancer is located and the size of the tumor.

The salivary glands are the most common site for adenoid cystic carcinoma. Your salivary glands produce saliva. Tumors in the salivary glands tend to grow along the nerves.

Your symptoms may include a painless lump in your mouth or throat, paralysis (weakened muscles) in the face or numbness in the face or neck. 

Adenoid cystic carcinoma can also develop in the breast, ear canal, hard palate, lacrimal gland, nasal cavity, reproductive organs (male and female), skin, tongue and trachea. But these cases are much rarer.

These are the symptoms that adenoid cystic carcinoma in other organs can cause:

• Breast: lump in the breast that is sometimes sore or painful to the touch
• Ear canal: painless lump in or on the ear, ear pain, hearing loss
• Hard palate: painless lump, swelling or numbness in the roof of the mouth
• Lacrimal glands: watery eyes, bulging eyes, double vision
• Nasal cavity: congestion, facial pain or pressure, nosebleeds
• Reproductive organs: abnormal vaginal bleeding or discharge, mass in the vulvar area, difficulty initiating urination, frequent urination, blood in urine
• Skin: sensitive skin, lesions on the skin that may be painful, swollen or draining blood or pus
• Tongue: difficulty swallowing, speaking or moving your tongue
• Trachea (windpipe): wheezing, hoarseness, shortness of breath

How is adenoid cystic carcinoma diagnosed?

Doctors will usually order imaging tests, like a CT scan or MRI, to get images of the affected area. Depending on your symptoms, you may also have a PET scan, an ultrasound or swallowing tests. A biopsy is the only way to officially diagnose adenoid cystic carcinoma.

Getting the correct diagnosis is important

Because adenoid cystic carcinoma is so rare, it’s not uncommon for people to be misdiagnosed. The tumors can look very different under a microscope, so pathologists who don’t see as many of these tumors may not be able to identify them as adenoid cystic carcinoma. We’ve had patients who’ve gotten a biopsy elsewhere and are diagnosed with a different type of cancer. Then they come to UT MD Anderson, and our pathologists review the slides and determine that they actually have adenoid cystic carcinoma.

Delayed diagnosis is another challenge. The most common symptom of adenoid cystic carcinoma is a painless lump, which can mimic many other conditions, including benign tumors. Adenoid cystic carcinoma typically grows slowly, so doctors may not initially think of it when they see a new lump, and instead, opt to wait and see if it grows.  

Misdiagnoses and delayed diagnoses can delay treatment or cause you to get the wrong treatment. That’s why it’s important to seek care at a comprehensive cancer center like UT MD Anderson that has pathologists who are experienced in diagnosing even the rarest of cancers.

How is adenoid cystic carcinoma treated?

Surgery followed by radiation therapy is the best treatment for localized adenoid cystic carcinoma tumors. “Localized” means the cancer is still confined to its original location in the body and has not metastasized, or spread.

The goal of surgery is to remove all or as much of the tumor as possible and then use radiation to kill any remaining cancer cells. If surgery is not an option, radiation is used to try to shrink the tumor or at least keep it from growing.

Adenoid cystic carcinoma can be tricky because it often comes back after treatment, sometimes years later. Most of the time, it returns as a distant recurrence. This means it has spread to other parts of the body. Adenoid cystic carcinoma typically does not spread to the lymph nodes.

Slow-growing adenoid cystic carcinoma usually comes back in the lungs. If you have lung metastases, your doctor may take a watch-and-wait approach to see if they grow larger and/or start causing symptoms. Your doctor may also recommend surgery or radiation to the lung metastases if there are only a few of them or if they are causing symptoms.

Chemotherapy or a type of targeted therapy called Vascular Endothelial Growth Factor Receptors (VEGFR) inhibitors may also be used to treat recurrent and metastatic adenoid cystic carcinoma.

Your care team will develop the best treatment plan for you.

Not all adenoid cystic carcinomas are the same

Adenoid cystic carcinoma is typically characterized as a slow-growing, stubborn cancer that often comes back in the lungs.

But that’s not always the case.

Researchers here at UT MD Anderson have identified a subgroup of patients who have an aggressive type of adenoid cystic carcinoma that grows quickly. This more aggressive type tends to spread to the bone and liver instead of the lungs.

If the cancer is caught early, we treat these patients right away.

What is the survival rate of adenoid cystic carcinoma?

Your prognosis will depend on many factors, including the cancer’s stage, the tumor’s characteristics and your overall health.

Your prognosis is better if you have a small tumor that can be cured with surgery and radiation rather than a metastatic tumor.

In general, people with early-stage adenoid cystic carcinoma have a 10-year survival rate of about 70%. In people with advanced disease, that 10-year survival rate can fall to around 30%.

Many patients can be cured. Not everybody has a recurrence, but when there is a recurrence, some people may live two years, while others may live more than 10 years.

We’re doing research at UT MD Anderson to find better markers to predict where patients are on that spectrum.

But remember, survival rates are just estimates of how long you will live after being diagnosed with or treated for cancer. It’s best to talk to your doctor about your specific prognosis. 

What research is UT MD Anderson doing to advance adenoid cystic carcinoma treatment?

One of the challenges of adenoid cystic carcinoma treatment is that there is no real standard of care. So, we’ve been researching to understand more about the tumor biology. This will help us develop new therapies and classify patients, so they get appropriate surveillance and the best treatment based on how the tumor behaves.

We did molecular profiling on 54 adenoid cystic carcinoma patients and found two different groups:

• ACC1 is associated with solid histology and mutations in the NOTCH1 gene. It is more aggressive and more likely to metastasize, leading to poorer prognoses.
• ACC2 is typically not solid and has increased expression of the TP63 gene and receptor tyrosine kinases. ACC2 has better survival rates.

Based on this research, we have launched clinical trials tailored for each ACC group.

Adenoid cystic carcinoma clinical trials are not available everywhere. If you are diagnosed with adenoid cystic carcinoma, it’s important to seek treatment at a comprehensive cancer center like UT MD Anderson. Our experts take a multidisciplinary approach to your treatment, and we have research opportunities that might not be available elsewhere.

It’s really an exciting time. A decade ago, there were no clinical trials available for these patients. Now, I’m leading or co-leading five active clinical trials for adenoid cystic carcinoma that are showing real promise.  Through my research, I plan to develop targeted therapies to help treat aggressive adenoid cystic carcinoma. I want to have better treatments – given to the right patients – that help extend patients’ lives and increase their quality of life.

Renata Ferrarotto, M.D., is a head and neck medical oncologist who specializes in treating salivary gland cancers and other rare head and neck cancers. She is also director of Head and Neck Medical Oncology Clinical Research at UT MD Anderson.

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