Approximately 1% to 10% of all basal cell carcinomas progress to an advanced stage. Not seeking care for concerning skin lesions is a big factor in the development of advanced stage skin cancer.

Basal cell carcinoma (BCC) is a type of skin cancer. Along with squamous cell carcinoma (SCC), it’s the most common of all cancer types.

The American Cancer Society (ACS) estimates that 5.4 million basal or squamous cell carcinomas are diagnosed in the United States each year. Of these, about 80% are BCC.

Many times, BCC remains localized to a single area. However, in rarer cases, it can spread deeper into surrounding tissues or to more distant tissues. This is called advanced BCC.

The article below will cover more about advanced BCC, the symptoms to be aware of, and how this type of cancer is diagnosed and treated.

BCC is advanced when it has spread deeper into surrounding tissues or to more distant parts of the body. It’s estimated that 1% to 10 % of BCCs progress to an advanced stage.

When advanced BCC has spread from the original lesion site and deeper into surrounding skin and tissues, it’s called locally advanced BCC. While this cancer remains at the original site, the extent of its spread makes it challenging to treat.

If advanced BCC has spread from the original lesion site to more distant tissues, it’s called metastatic BCC. This type of advanced BCC is very rare, accounting for less than 1% of all BCCs.

The most common metastatic site for BCC is the lymph nodes. However, it may also spread to the bones, lungs, and liver.

Advanced BCC arises from an earlier cancerous lesion that wasn’t treated or has recurred after treatment. This type of cancer most commonly appears on areas that are frequently exposed to sunlight, such as the:

  • face
  • scalp
  • ears
  • neck
  • shoulders or upper back

The ways that BCC can present are very diverse. Some examples of potential signs of BCC can be:

  • a scaly, irritated patch of skin that’s slightly raised
  • a sore or pimple-like lesion that doesn’t heal and may ooze or bleed
  • a shiny bump that’s similar to your skin tone and may be mistaken for a mole
  • a pink or reddish area that dips in at the center
  • a flat, waxy area that looks similar to a scar

Don’t hesitate to see a doctor if you have any suspicious skin lesions

If you notice a suspicious skin lesion, especially on your scalp, face, neck, or shoulders, have a dermatologist check it out. If it’s BCC, early treatment can help to prevent advanced BCC.

Locally advanced BCC

When BCC becomes advanced, the lesion typically becomes noticeably larger. It may also become ulcerated and not heal. As locally advanced BCC grows and spreads further, it could cause severe tissue or bone damage.

Multiple lesions may also be present in locally advanced BCC. A 2022 study of 433 people with locally advanced BCC found that almost 23.3% of participants had multiple BCC lesions. The median number of lesions was three per individual.

Metastatic BCC

The exact symptoms of metastatic BCC can vary depending upon where the cancer has spread to. However, some general symptoms to look for are:

BCC is caused by DNA changes in basal skin cells that promote uncontrolled cell growth and division. Many BCCs are caused by changes affecting the hedgehog signaling pathway.

This pathway is involved in regulating cell growth and division. When it isn’t functioning as it should, the basal cells begin to grow and divide out of control.

The main driver of changes that lead to BCC is exposure to ultraviolet (UV) radiation, which is found in sunlight and in tanning beds. Other risk factors for BCC include:

BCC is typically a slow growing cancer. That means that it may take several years for it to become advanced.

Skin cancer prevention strategies

There are several steps that you can take in your daily life to help prevent developing BCC:

  • Always use a water-resistant sunscreen with an SPF of 30 or higher when you’ll be outside. Be sure to reapply every 2 hours.
  • Try to stay in the shade when you’re outside and aim to avoid outdoor activities when the sun’s rays are strongest. This is typically between 10:00 AM and 2:00 PM.
  • Be conscious of the fact that water, sand, and snow can reflect sunlight back at you and increase your chances of getting a sunburn.
  • Wear clothing that protects you from the sun if you’ll be outside for a while. Some examples include sunglasses, a wide-brimmed hat, and light, breathable clothing, ideally with UV protection.
  • Don’t use tanning beds and consider trying out a self-tanning product instead.
  • Do regular skin self-checks to look for any suspicious or concerning spots.

A 2022 review notes that not seeking care for concerning skin lesions is a big factor in the development of advanced BCC. That’s why it’s so important to see a dermatologist if you’re worried about a spot on your skin.

In order to diagnose advanced BCC, a dermatologist will first take your medical history. They’ll ask you about topics like:

  • when you first noticed the lesion
  • if the lesion has changed in size or appearance since it first appeared
  • any other symptoms associated with the lesion, such as itching, pain, or bleeding
  • whether or not you’re having any other symptoms
  • whether you have a personal or family history of skin cancer

They’ll then do a skin exam. During this time, they’ll evaluate the lesion both by looking at it and by using a special magnifying glass called a dermatoscope. They’ll likely examine the rest of your skin as well.

They may also feel your lymph nodes to see if they’re swollen. This can be a sign that cancer has spread to the lymph nodes.

Collecting a biopsy sample from the lesion is an important part of the diagnosis. A biopsy sample can be viewed under a microscope to see if cancer is present. If so, the type of cancer can also be determined.

If your dermatologist thinks that the cancer has metastasized, they may do other tests. These can include a lymph node biopsy and imaging tests to see if there’s cancer in more distant parts of the body.

Surgery and radiation therapy are two common treatments for BCC. In some situations, these may also be used for some types of advanced BCC.

However, many people with advanced BCC can’t be treated with these methods due to the size of the cancer, its location, or how far it has spread.

This means that a systemic treatment is needed. A systemic treatment is one that works throughout the whole body.

The Food and Drug Administration (FDA) has approved three systemic treatments for advanced BCC rather recently. Let’s explore these now.

Targeted therapy

Targeted therapy uses drugs that target specific aspects of cancer cells. The targeted therapies used for advanced BCC are:

Both of these drugs inhibit the hedgehog pathway. As we mentioned above, this pathway is involved in many BCCs, including advanced BCC. When the hedgehog pathway is inhibited, BCC can’t grow and spread as quickly.

A 2018 review of studies looked into the efficacy of these drugs:

  • Locally advanced BCC: Both vismodegib and sonidegib had similar overall response rates (69% versus 57%, respectively). However, vismodegib had a higher complete response rate than sonidegib (31% versus 3%).
  • Metastatic BCC: The overall response rate for vismodegib was found to be 2.7-fold higher than that of sonidegib (39% versus 15%, respectively). The lower response rate is one of the reasons sonidegib isn’t approved for metastatic BCC.

Immunotherapy

Immunotherapy is a type of cancer treatment that helps to boost your immune system’s activity against a cancer. Cemiplimab (Libtayo) is an immunotherapy drug that was approved by the FDA for the treatment of advanced BCC in 2021.

Cemiplimab is a programmed cell death 1 (PD-1) blocking antibody, which is a type of immune checkpoint inhibitor. It works by blocking immune checkpoints, which prevent immune cells from effectively finding and killing cancer cells. When the checkpoints are blocked, immune cells are free to detect and kill cancer cells. PD-1 inhibitors work well for aggressive cancers like metastatic melanoma.

A 2021 study looked at the effectiveness of cemiplimab in people with advanced BCC for whom targeted therapy had been ineffective. Approximately 6% of participants had a complete response to cemiplimab, while 25% had a partial response.

Generally speaking, the outlook for people with advanced BCC is poorer than that for people with an earlier stage of BCC. This is because the cancer has spread further and, as such, can be more challenging to treat.

According to the ACS, the number of people who die due to BCC and SCC is unknown because these cancers aren’t tracked by cancer registries. It’s thought that 2,000 people in the United States die from BCC and SCC each year.

Several factors can affect the outlook for people with advanced BCC. These include:

  • the size and location of the cancer
  • how far the cancer has spread, including if it has metastasized
  • whether or not the cancer is a recurrence of a previous BCC
  • how the cancer responds to the recommended treatment
  • your age and overall health

If you’ve received an advanced BCC diagnosis, ask a care team about your outlook. They can evaluate the factors above to give you a better idea of what to expect individually.

BCC becomes advanced when it has spread deeper into surrounding tissues or to more distant tissues in the body. Since BCC is a slow growing cancer, this typically happens over a period of several years.

Advanced BCC is more difficult to treat than early BCC, often due to the location, size, and extent of the cancer. However, newer systemic treatments can help to improve your outlook when surgery or radiation therapy isn’t recommended.

When BCC is identified and treated early, the outlook for people with this condition is very good. As such, be sure to consult a dermatologist if you notice any new or worrisome skin lesions. A dermatologist can help to determine whether it’s cancer and, if so, take steps to treat it early.