Basal cell carcinoma (BCC) is the most frequently occurring type of skin cancer, representing 90% of the eye's malignant melanomas. In the US alone, more than 4 million people develop BCC annually. Patients usually slowly develop multiple, primary, unnoticeable tumors over time. BCC often develops on the surface of hair-bearing skin that has been exposed to sunlight. The most affected areas are the head, neck, trunk, and other exposed areas. The nodular type is the most common, while others include superficial, ulcerative, sclerosing, and erythematous. BCC rarely metastasizes (spreads) to other body parts and instead can destroy nearby tissues. It can grow near the eyes, mouth, brain, or ears, and it can turn fatal (rarely).
As Known As
- Rodent Ulcer
- Basal Cell Cancer
- Basal Cell Epithelioma
- Basal Cell Skin Carcinoma
- Skin Basal Cell Carcinoma
- Basal Cell Carcinoma of Skin
- Basal Cell Carcinoma of the Skin
Causes & Risk Factors
BCC is caused by exposure to the sun, especially in those with light skin. Exposure to the sun triggers changes in DNA mutations in the patched tumor suppressor gene (part of the hedgehog signaling pathway), leading to BCC. Radiation triggers the abnormal, uncontrolled growth of basal cells and subsequent DNA changes.
Risk factors include:
- Immune suppression
- Exposure to the sun or ultraviolet (UV) rays
- Age, where BCC mostly affects individuals over 50
- Skin cancer history such as BCC, melanoma, and squamous cell carcinoma
- Long-term exposure to arsenic (chemical element mostly found in minerals)
- Radiation therapy (cancer treatment) and indoor tanning (for cosmetic purposes)
- Sex, where males are more prone to attack even though BCC can be found in females and younger adults
- Chronic infections, injury, skin inflammation from burns and scars, or disease (such as cutaneous lupus)
- Fair or light-skinned individuals, blue eyes, and red or blond hair even though it can affect darker individuals (rarely)
- Inherited syndromes such as xeroderma pigmentosa, Oley syndrome, Gorlin syndrome, Rombo syndrome, and Bazex-Dupré-Christol syndrome
Signs & Symptoms
Since there are several patterns found in BCC (approximately over 20), it may present a variety of signs and symptoms. For example, the nodular form starts as a tiny, glossy, firm growth that may appear clear to pink in color before visible dilated blood vessels appear a few months to years later. The tumor’s centre may break or bleed, form a scab and sometimes heal, causing the assumption that it is a sore and not cancer. A superficial BCC sign includes a flat, thin, red/pink patch. BCC looks different from person-to-person.
Generally, signs and symptoms of BCC include:
- Crusting of the skin
- Bleeding and ulceration
- A lesion that refuses to heal
- Asymptomatic in some cases
- Madarosis (loss of eyelashes)
- Normal eyelid margin distortion
- Slow-growing nodule or lesion (often pink-colored or pigmented)
- Paraesthesia (extended numbness after local anesthesia administration)
- Varied sizes from a diameter of a few millimeters to several centimeters
- The lesion looking like a sore, red patch, pink growth, shiny bump, or growth
The doctor will take a history of any suspicious lesion. He/she will perform an eye examination and assess the lower eyelid because BCC is prone to attacking the lower eyelid. An eye examination also includes proptosis (abnormal protrusion) and ocular motility (concerned with eye movement) assessment.
The doctor will recommend a biopsy, which is the standard procedure for confirming BCC's diagnosis. In a biopsy, the doctor removes a small part of the tumor, which is examined under a microscope.
Further examination of the tumor includes:
- Skin ulceration
- Loss of eyelashes
- Eyelid malposition
- Extent of the tumor
- General appearance
- Dilated blood vessels
The lesions on the limbs and trunk are also clinically diagnosed.
BCC is treated according to the tumor’s size, type, and position. It is also dependent on the number of lesions to be treated and specific patient factors. Prompt treatment is recommended because if left untreated, it can lead to complications.
The tumor can be treated with medications such as imiquimod 5%, a cream, although it may not be as effective as surgical removal.
There are a variety of surgical options that can be used in the treatment of BCC. For small lesions, electrosurgery (curettage and electrodesiccation) destroys cancer cells using a curette (sharp instrument) and heat or a chemical agent to stop the bleeding and seal off the wound. Excisional surgery is used in the early stages of BCC. The surgeon uses a scalpel to remove the entire tumor along with its margins and sends it to the lab for examination. Mohs surgery is the gold standard, most effective procedure for treating BCC. The surgeon removes the lesion and a tiny tissue margin around and below the tumor. The technique may be repeated severally until no evidence of BCC exists. It is recommended for large, aggressive, recurrent, and rapidly growing tumors.
Cryosurgery is effective for small and superficial BCCs and patients with bleeding problems. The doctor uses a spray device or cotton-tipped applicator to freeze the tumor by applying liquid nitrogen.
Radiation therapy is non-invasive and makes use of an X-ray beam with low energy to destroy the lesion. It is used for troublesome tumors that surgery cannot treat, in older patients and those with poor health who cannot withstand surgery.
In photodynamic therapy, photosensitizers are applied to the target area alongside a pulse-dye laser to destroy cancer cells. The patient is then required to avoid the sun for at least 48 hours to avoid severe sunburns.
BCC is rarely fatal, and treatment is nearly always successful if an appropriate treatment method is employed, the lesion is small, and if the lesion is in its early stages. However, there is the risk of recurrence within five years of the initial appearance in about 25% of patients with a history of BCC. Recurrences often occur in patients with lesions bigger than 3cm, deeply invasive lesions, long-standing tumors, and inadequate treatment. Left untreated, BCC can invade bones, skeletal muscles, and subcutaneous fat, leading to loss of sensation, loss of function, and rarely death.
Prevention & Follow Up
Since radiation from UV rays is the most significant cause of BCC, preventive measures involve avoidance.
These measures include:
- Using sunblock products such as sunscreens containing at least SPF 30
- Protective clothing like hats and appropriate clothing (such as long-sleeved shirts, pants, etc.)
- Avoiding sun exposure. An individual can minimize outdoor activities, especially when the rays are strongest (between 10 am-4 pm) and avoid sunbathing and tanning beds.|
Due to the risk of a recurrence, an individual cured of BCC should undergo an annual check-up. Investigations should be done if any changes to the skin last for more than a few weeks. Regular self-examinations are recommended.