What Is Basal Cell Carcinoma? Symptoms and Treatment

Basal Cell Carcinoma (BCC) is the most common skin cancer in the world, accounting for about 80% of all skin cancers. Although BCC rarely spreads to other organs, if left untreated it can grow and severely damage the surrounding tissue, especially on the face. Knowing what it looks like and how to spot it early makes treatment easier and more effective.

Causes and Risk Factors of BCC

The most important factor is long-term cumulative exposure to UV rays from sunlight. Other risk factors include:

• Skin colour — Fair skin (Fitzpatrick I-II) that burns easily and rarely tans

• Family history — A family member who has had skin cancer

• Behaviour — Use of tanning beds

• Medical factors — Weakened immune system and abnormalities of the PTCH1 and TP53 genes

Appearance and Symptoms

BCC usually appears on skin that is often exposed to the sun, such as the face, above the ears, the neck and the backs of the hands. Common types include:

• Nodular BCC — A shiny, pearly, flesh-coloured bump (pearly nodule) with tiny blood vessels (telangiectasia) on the surface. There may be a sore in the centre that is slow to heal.

• Superficial BCC — A flat, raised red patch on the trunk that looks like a chronic inflamed rash.

• Warning sign — A sore or bump on the skin that does not heal within 3-4 weeks should be checked by a doctor.

Diagnosis

The doctor examines the skin with the naked eye and a dermatoscope, and confirms the result with a skin biopsy for pathology testing. If you have a bump, sore or skin mark that is abnormal and does not heal within 3-4 weeks, see a dermatologist for evaluation.

Treatment of Basal Cell Carcinoma

Treatment depends on the location, size, subtype and overall health of the patient:

• Excisional surgery — Removal with a margin of at least 4-5 millimetres of normal tissue. Suitable for small to medium nodular BCC.

• Mohs Micrographic Surgery — Suitable for BCC on the face, large, aggressive or recurrent BCC, with a success rate of more than 99%.

• Radiation therapy — Used in older adults who cannot have surgery.

• Topical treatment — Imiquimod or 5-fluorouracil for superficial BCC.

• Hedgehog pathway inhibitors — Vismodegib or sonidegib for advanced or metastatic cases.

Follow-up and Prevention

Without adequate follow-up, BCC has about a 30-50% chance of coming back within 5 years after treatment. Doctors therefore usually schedule check-ups every 6-12 months during the first 2-5 years. The key to prevention is applying sunscreen of SPF 30 or higher year-round, wearing sun-protective clothing, and avoiding strong sun between 10:00 and 16:00.

Frequently Asked Questions About Basal Cell Carcinoma

Is BCC life-threatening? BCC very rarely spreads to other organs, so it is seldom life-threatening. However, if left untreated it can grow and destroy surrounding tissue and bone, especially on the face, so it should be treated early.

What kind of sore should be suspected as BCC? A bump or sore on sun-exposed skin that is shiny and pearl-like, has tiny blood vessels, or is a sore that does not heal within 3-4 weeks should be examined by a dermatologist.

Can BCC be completely cured? If detected and treated early, the chance of cure is very high, especially with Mohs surgery, which has a success rate of more than 99%. However, continued follow-up is needed because it can come back.

How can BCC be prevented? It can be prevented by reducing exposure to UV rays, such as applying sunscreen regularly, wearing protective clothing and a hat, avoiding strong sun, and not using tanning beds.

BCC skin cancer responds very well to treatment when found early. If you have a skin bump or sore that does not heal, or you are concerned, you should be examined by a specialist. Consult a dermatologist at Siam Dermatology: call +66 61 448 7000 or LINE @siamderm

Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed July 16, 2026