Acinic cell carcinoma (ACC) of the parotid is a rare tumor and therefore information compared to other tumor types is relatively limited.
Answering questions about ACC is Apostolia Tsimberidou, M.D., Ph.D., associate professor in the Department of Investigational Cancer Therapeutics at MD Anderson.
What is acinic cell carcinoma?
Acinic (or acinar) cell carcinoma of the parotid gland is a rare tumor that represents approximately 10% of salivary gland tumors. This tumor is usually a low-grade, highly differentiated carcinoma. Women are affected with salivary gland tumors more than men, and the average age of diagnosis of all salivary gland tumors is approximately 44 years old.
What causes ACC?
While the cause of salivary gland tumors is unknown, risk factors include: cigarette smoking, genetic predisposition, viral infections, rubber manufacturing, plumbing equipment and some types of woodworking, as well as asbestos mining and exposure to nickel compounds. The only well-established risk factor is ionizing radiation.
Workplace exposure to certain radioactive substances may also increase the risk of salivary gland cancer. In rare instances, members of some families seem to have a higher than usual risk of developing this type of cancer.
The clear causes are unknown. As with every type of cancer, avoidance of potential risk factors might help prevent this disease.
What are common symptoms of ACC?
Clinically, patients typically present with a slowly enlarging mass in the parotid region. Pain is a symptom in more than 33% of patients.
How is ACC treated?
Surgical excision is the most common treatment for ACC, but radiation therapy may be used in some cases. The facial nerve is in the salivary gland and should be preserved if not involved with the tumor.
Most deep parotid tumors require postoperative radiation therapy because of the limitations in resection of these tumors, or radiation therapy is given as additional therapy for tumors that are intermediate or high grade.
Various chemotherapeutic agents may be used to treat advanced ACC.
What are the survival rates and statistics for those diagnosed with ACC?
Staging is likely a better predictor of outcome than histological grading. According to data from the Atlas of Genetics and Cytogenetics in Oncology and Haematology, "Acinic cell carcinoma tends to recur in 35% of cases, and the rate of disease-associated death is about 16%."
Are there clinical trials available for ACC patients?
Patients with ACC are usually candidates for the same treatment as patients with other tumors of the salivary gland.
To enable the selection of optimal therapy, patients can also enroll in tumor molecular profiling, identification of molecular aberrations or new clinical trials as they become available.
What advice would you give to newly diagnosed or current patients with ACC?
To new patients, I recommend that they be treated by a group that can obtain multidisciplinary management including oncologists, radiation therapists, pathologists, and radiologists.
The use of molecular profiling to identify genetic markers that drive tumor pathogenesis, progression and participation in clinical trials with targeted agents using the "personalized medicine" approach (treating a patient with a drug that inhibits the function of the specific molecular aberration that the patient may have) is expected to improve the clinical outcomes of patients with this disease, as with other types of cancer.
Current patients should work with their physician to closely monitor their disease.
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