Adenoid cystic carcinoma (ACC) is a rare form of adenocarcinoma, which is a type of cancer. ACC can exist in many different body sites. It most often occurs in the areas of the head and neck, in particular the salivary glands. ACC also has been reported in the breast, lacrimal gland of the eye, lung, brain, bartholin gland, and the trachea.
Compared with most other carcinomas, ACC has a slow course with a survival rate of 89 percent at five years. Tumors progress persistently and often recur, resulting in a survival rate of only 40 percent after 15 years. It is treated as a chronic condition. Remote metastases can occur a decade or more after initial treatment of the primary tumor, with the most common metastatic locations being the lung, bone, and viscera.
The preferred surgical treatment at UPMC for adenoid cystic carcinoma of the sinuses and skull base is the Endoscopic Endonasal Approach (EEA) to remove the tumor. This innovative, minimally invasive technique uses the nose and nasal cavities as natural corridors to access hard-to-reach or previously inoperable tumors. EEA offers the benefits of no incisions to heal, no disfigurement to the patient, and a faster recovery time. If complementary treatments, such as radiation therapy, are needed, those therapies can begin soon after surgery.
ACC tumors have a distinctive pattern in which abnormal bundles of epithelial cells surround and/or infiltrate ducts or glandular structures within the affected organ.
Your doctor will perform a physical exam and will ask about any symptoms you are having. Symptoms vary depending on the site and origin of the tumor. Lesions of the salivary glands cause painless, slow-growing masses in the mouth or face. Tumors of the lacrimal glands may cause bulging of the eyes and changes in vision. Tumors in the tracheobronchial tree may cause respiratory symptoms, such as dyspnea (shortness of breath), while the presence of tumors in the larynx may lead to changes in speech.
Pain, numbness, and nerve paralysis may accompany advanced tumors because they can infiltrate and spread along nerves.
Diagnosis is made through microscopic evaluation of the tumor cells, which are obtained via a biopsy. Recurrences of ACC are usually identified by imaging techniques such as MRI and CT scans.
The standard treatment for ACC is surgical removal of the malignant (cancerous) tissue. The surgeon will remove the tumor and an area of tissue surrounding it. The presence of clean margins, meaning a minimum of 2 mm of tissue is cancer-free surrounding the tumor, signals total tumor removal and gives the best chance that cancer will not recur at that site.
Adenoid cystic carcinomas of the sinuses and skull base can be approached directly through the Endoscopic Endonasal Approach (EEA). This state-of-the-art, minimally invasive surgical procedure uses the nose as a natural corridor to reach these lesions. There are no incisions in the skin of the face or head.
Surgery usually is followed by radiation therapy. Patients who received surgery with the Endoscopic Endonasal Approach may be able to begin radiation therapy soon after surgery.
Neutron therapy also may be used to treat ACC. Compared with conventional radiation therapy, neutrons can deliver 20 to 100 times more energy along their path length, causing much greater damage to the cancer cells. Neutron radiation therapy has been tested on many different types of tumors, with salivary gland tumors showing the greatest benefit. In certain instances, it may be the treatment of choice for ACC, particularly in areas of the body where it is difficult to perform surgery.
Neutron therapy carries more severe side effects than conventional radiation therapy, such as severe sore mouth and/or throat and difficulty swallowing, and therefore is used more often in cases where the disease is inoperable or recurrent.