What Happens if Basal Cell Carcinoma Is Left Untreated?

Medically reviewed by Paul A. Regan, M.D., FAAD

Written by Emily Van Devender

Posted on July 14, 2026

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Key Takeaways

Basal cell carcinoma, or BCC, is the most common type of skin cancer and is often curable when found and treated early.

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Basal cell carcinoma (BCC) is the most common type of skin cancer. BCC is often curable when found and treated early. But what happens when treatment is delayed or avoided?

Left untreated, BCC may:

Spread deeper into the skin or to other parts of the body
Become harder to treat
Cause scarring or changes in appearance

Read on to learn more about the risks of BCC spreading and what can happen when it goes untreated.

🗳️ Are you or your loved one delaying treatment for BCC? If so, why?

Treatment risks feel too high

Age or other health concerns

Fear of treatment

Another reason

Basal Cell Carcinoma Can Grow and Spread

It’s rare for BCC to metastasize (spread beyond its first site on your skin), but it can happen over time without the proper treatment.

Over time, a BCC lesion can:

Grow into deeper layers of skin and tissue around the original area
Grow deep enough to reach bone — This happens rarely.
Metastasize to other parts of the body — This occurs in less than 1 percent of BCCs.

Where Does Basal Cell Carcinoma Spread?

Like other types of cancer, BCC can spread to the lymph nodes — small, bean-shaped structures located throughout the body that are part of the lymphatic and immune systems. From there, the cancer can travel to other body parts. After the lymph nodes, the most common areas for BCC to spread are the lungs or bones.

You may notice swollen, tender, or painful lymph nodes if BCC has spread there. Tell your doctor right away if you’ve been diagnosed with BCC and develop swollen lymph nodes.

Basal Cell Carcinoma May Become Incurable

Most early-stage cancers are curable with treatment.

Mohs surgery, the gold-standard treatment for many basal cell carcinomas, has a cure rate of up to 99 percent when used to treat a tumor for the first time.

Excision, a surgery that removes the cancer and some nearby healthy skin, has a cure rate above 95 percent for BCC lesions that haven’t spread yet.

It’s rare but possible for BCC to metastasize and become incurable. Instead, you may need cancer treatments like immunotherapy or chemotherapy to try to slow the cancer’s spread.

The survival rate for BCC is quite high. However, aggressive BCCs that have spread to other parts of the body can be life-threatening, especially when left untreated.

It’s Also More Likely To Come Back

When treatment is delayed, BCC lesions have a higher risk of coming back. A BCC lesion that went untreated for some time may come back repeatedly.

Untreated Basal Cell Carcinoma Can Change Your Appearance

Disfigurement is one of the most common complications of untreated BCC. Major changes in appearance from skin cancer or skin cancer surgery can affect your self-esteem and quality of life.

Because these areas get the most sun exposure, BCC commonly develops on the:

Nose
Forehead
Cheeks

If BCC spreads deeper into tissue or even bone, more extensive surgery may be needed to remove the lesion and surrounding tissue.

BCC on the face may be harder to treat if it grows into nearby tissue. Treating BCC early can help lower the chance that you’ll need major surgery or reconstruction. When BCC develops near the eyes, advanced BCC or surgery in that area may affect vision.

You May Need Reconstructive Surgery

Deep excision surgery for advanced BCC in these areas can leave significant scarring and change your appearance. Extensive scarring in other areas, such as your feet or hands, may also need reconstruction.

Who’s Most at Risk for Basal Cell Carcinoma Spreading?

Although BCC rarely spreads, the risk may be higher in certain situations.

Tumor-related factors include:

Very large, or “giant,” BCCs
Tumors that first develop on the head or neck
BCC that returns after treatment

Other factors linked to a higher risk include:

Developing BCC at an older age
Having a weakened immune system
Having a history of radiation therapy
Being a man — Men are twice as likely to develop metastatic BCC as women, according to Moffitt Cancer Center.
BCCs in people with a weakened immune system

When Do the Risks of Treating Basal Cell Carcinoma Outweigh the Benefits?

For some older adults who are in poor health, standard BCC treatments may not be safe options. A surgery that is usually minor for a healthy, younger person may carry too many risks and offer little benefit. These risks can include surgical complications, such as heavy bleeding or skin infections.

For some older adults who are in poor health, treatment may have more risks than benefits. Instead, doctors may recommend a “watch-and-wait” approach.

In these cases, your skin cancer care team may recommend against treatment, at least at first. Instead, they may recommend active surveillance of the BCC. Active surveillance, also known as “watch and wait,” involves monitoring the BCC lesion for signs that it may need treatment.

Talk to Your Doctor

Finding and treating BCC early can help you avoid complications or the need for reconstructive surgery.

Finding and treating basal cell carcinoma early can help you avoid complications or the need for reconstructive surgery.

If you have concerns about BCC or your risk of BCC spreading, talk to your dermatologist or cancer care team. A team of specialists, including oncologists, dermatologists, and dermatologic surgeons, can help you understand your treatment options and choose the best next step.