Why does tongue cancer cause a mouth sore that does not heal?

Cancerous cells can grow into the tongue's surface and deeper layers. This may leave an ulcer or raw area that is repeatedly disturbed by chewing, speaking, or contact with teeth. The tissue may bleed, feel painful or numb, or develop a firm edge. A persistent sore can also have non-cancer causes, including trauma, infection, irritation, or another mouth condition, so its appearance alone cannot identify the cause.

A clinician may inspect the tongue, feel nearby tissue and lymph nodes, and arrange a biopsy if the area remains concerning. A biopsy is the way abnormal cells are checked directly.

Arrange an oral examination if the sore is not healing, keeps returning in the same place, or is changing. Until then, avoid tobacco, alcohol-based mouthwash, and foods that sting the area. Choose softer foods, use a gentle toothbrush, and do not scrape or pick at the sore. Tell the clinician about pain, bleeding, numbness, swallowing changes, voice changes, and any neck lump.

Seek urgent medical help if swelling makes breathing difficult, you cannot swallow fluids, bleeding does not stop with gentle pressure, or pain and swelling are rapidly worsening. Otherwise, book a prompt appointment for a sore that persists, especially when it is accompanied by a neck lump, unexplained weight loss, or reduced tongue movement.

Ask what might be causing the sore, whether a dental or medication-related irritation could explain it, whether a biopsy is needed, and how to protect the area while it is being assessed.