Acinic Cell Carcinoma (Salivary Gland), from the CureRays guide library.

Acinic cell carcinoma is a usually slow-growing, low-grade salivary-gland cancer most often found in the parotid gland, treated mainly with surgery and, when needed, radiation — with an excellent outlook for most patients.

What it is.

Acinic cell carcinoma is a type of salivary-gland cancer that begins in the cells that normally produce saliva. It is most common in the parotid gland — the large salivary gland in front of and below the ear — but can also arise in smaller salivary glands. Most acinic cell carcinomas are low-grade, meaning they tend to grow slowly and rarely spread, and they carry an excellent long-term outlook. It is one of the more common salivary cancers in younger adults and even occasionally in children. In recent years, doctors have learned that some tumors once labeled 'acinic cell carcinoma' are actually a separate, gene-fusion-driven cancer called secretory carcinoma; modern testing now distinguishes the two, because the treatments and outlooks can differ. A small minority of acinic cell carcinomas are high-grade or undergo 'high-grade transformation,' behaving more aggressively and requiring more intensive treatment.

How radiation treats it.

Radiation damages the DNA inside cancer cells so they can no longer divide. For acinic cell carcinoma, surgery is usually the main treatment, but radiation is an important partner after surgery when the tumor is high-grade, the margins are close or positive, a nerve is involved, or lymph nodes are affected — it treats the microscopic cells left behind and lowers the chance of the cancer returning. Intensity-modulated radiation shapes the dose around the salivary region and neck while sparing healthy glands and swallowing muscles. For tumors near the skull base or those needing re-treatment, proton therapy can further spare nearby tissue. Radiation is painless during delivery, given over several weeks of daily sessions, and external-beam treatment leaves no radioactivity in the body.

The ways we can treat it.

Intensity-modulated radiation (IMRT). Beams are shaped around the salivary region and neck to treat the tumor bed while sparing the other salivary glands, swallowing muscles, and jaw to limit dry mouth and other side effects.

Proton therapy (selected). Protons can reduce dose to nearby structures for tumors near the skull base or when re-treating an area, lowering side effects.

Neutron / particle therapy (selected high-grade). For certain aggressive salivary cancers that resist standard radiation, specialized particle beams at expert centers can improve local control.

Questions we hear often.

Is acinic cell carcinoma usually serious? Most acinic cell carcinomas are low-grade and slow-growing, with an excellent outlook after surgery. A minority are high-grade or undergo high-grade transformation and behave more aggressively, needing surgery, radiation, and close follow-up. Your team bases the plan on your tumor's grade and stage.

Will I lose my facial movement after parotid surgery? The facial nerve runs through the parotid gland, so surgeons take great care to identify and protect it. Most patients keep normal facial movement; temporary weakness can occur and usually improves. Your surgeon will discuss the specific risks for your tumor's location.

Why does it matter to tell it apart from secretory carcinoma? The two look similar but are different cancers. Secretory carcinoma is defined by a gene fusion (ETV6-NTRK3) that makes targeted NTRK-inhibitor pills an option for advanced disease. Modern molecular testing distinguishes them so each is treated correctly.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.