Adenoid cystic carcinoma

Adenoid Cystic Carcinoma (ACC)

Adenoid Cystic Carcinoma is a rare form of adenocarcinoma, which is a type of cancer that begins in glandular tissues surrounding various organs. Most commonly, ACC is found in the salivary glands.

About the Salivary Glands:

The salivary glands produce saliva, which plays several important roles in the body:

• Moistens the mouth: Saliva helps keep the mouth moist.
• Aids in digestion: Saliva helps break down food during digestion.
• Prevents infections: Saliva helps prevent infections in the mouth and throat.

There are two main groups of salivary glands:

1. Minor Salivary Glands: These are small groups of glands located in the head and neck regions. They are found in areas such as the roof of the mouth, the upper part of the throat, the back of the nasal passages, the base of the tongue, the inner lining of the mouth, the windpipe (trachea), and the voice box (larynx).
2. Major Salivary Glands: There are three pairs of major salivary glands:
• Parotid Glands: The largest salivary glands, located in front of each ear.
• Submandibular Glands: Found beneath the jawbone.
• Sublingual Glands: Located under the tongue.

What is Adenoid Cystic Carcinoma?

In ACC, cells in the salivary glands grow uncontrollably, forming a tumor. This tumor may or may not be cancerous. ACC has an unpredictable growth pattern. In some cases, the tumor may remain stable for a long time without growing, while in others, it may suddenly begin to grow aggressively. ACC can spread via nerve invasion (perineural invasion) or through the bloodstream, rather than through lymph nodes, which is common in other cancers. It most frequently spreads to the lungs.

Statistics:

As a rare cancer, there is no definitive data available for India. However, in the United States, approximately 1,300 cases of ACC are diagnosed each year.

Risk Factors:

The exact cause of Adenoid Cystic Carcinoma is still unknown, and no specific risk factors have been scientifically proven.

Symptoms:

The early symptoms of ACC depend on which salivary gland is affected. In the initial stages, the tumors may grow slowly and painlessly. Other symptoms include:

• A lump in the upper mouth, under the tongue, or at the floor of the mouth.
• Numbness or tingling in the jaw, tongue, face, or mouth.
• Difficulty swallowing.
• Hoarseness or a rough voice.
• Dull, persistent pain.

Diagnosis:

1. Biopsy: This involves taking a small sample of tissue from the tumor. It can be done in two ways:
• Fine Needle Aspiration Cytology (FNAC): A thin needle is used to extract cells and fluids from the tumor for examination.
• Surgical Biopsy: A small section of the tumor is surgically removed and examined under a microscope.
2. MRI: Magnetic Resonance Imaging is used to get detailed images of the affected area.
3. CT Scan: A computerized tomography scan provides cross-sectional images to detect tumor size and spread.
4. PET-CT Scan: This combines a PET scan with a CT scan to provide detailed images of cancer spread.

Stages of Adenoid Cystic Carcinoma:

Tumor Size:

• TX: The primary tumor cannot be evaluated.
• T0: No evidence of a tumor.
• T1: The tumor is small, less than 2 cm in size, and non-aggressive.
• T2: The tumor size ranges between 2 cm and 4 cm, with no aggressive behavior.
• T3: The tumor is between 4 cm and 6 cm, has spread beyond the salivary gland, but has not affected the facial nerve.
• T4a: The tumor has spread to the skin, jawbone, ear, or facial nerve.
• T4b: The tumor has spread to the skull base, nearby bones, or major arteries.

Node Involvement:

• NX: Lymph nodes cannot be evaluated.
• N0: No evidence of cancer in the lymph nodes.
• N1: Cancer has spread to a single lymph node on the same side of the body as the tumor, with the node being less than 3 cm in size.
• N2a: Cancer has spread to a lymph node on the same side as the tumor, with the node size between 3 cm and 6 cm.
• N2b: Cancer has spread to multiple lymph nodes on the same side, with none larger than 6 cm.
• N2c: Cancer has spread to multiple lymph nodes on both sides, but none larger than 6 cm.
• N3: Cancer has spread to one or more lymph nodes, with at least one node larger than 6 cm.

Metastasis:

• MX: Distant metastasis cannot be evaluated.
• M0: No distant metastasis.
• M1: Cancer has spread to distant parts of the body.

Treatment for Adenoid Cystic Carcinoma:

1. Surgery:
• The best treatment for ACC is the surgical removal of the tumor. During surgery, the tumor and a small margin of healthy tissue around it are removed. Since ACC can spread through nerves, the surgeon may need to decide whether to remove affected nerves.
• Side effects of surgery depend on the location of the tumor. If nerves are involved, it may lead to facial paralysis or numbness.
2. Radiation Therapy:
• Radiation therapy is used after surgery to destroy any remaining cancer cells. A specialized form of radiation called Intensity-Modulated Radiation Therapy (IMRT) delivers high doses of radiation directly to the tumor while minimizing damage to the surrounding healthy tissues.
• Side effects of radiation therapy may include dry mouth and loss of salivary gland function, which can lead to mouth dryness and dental issues.

Follow-up for Adenoid Cystic Carcinoma:

Regular follow-up tests are essential after completing treatment to monitor for cancer recurrence and manage any side effects. Follow-up care includes routine physical exams, blood tests, and imaging tests to ensure that the cancer has not returned.

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