What Is the Difference Between BCC and SCC Skin Cancer?

Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the two most common types of non-melanoma skin cancer.

Both are strongly associated with cumulative ultraviolet exposure, but they behave differently. Understanding the distinction can help explain why some skin cancers can be treated relatively simply, while others require more urgent or extensive treatment.

What is a basal cell carcinoma (BCC)?

BCC develops from cells associated with the basal layer of the epidermis.

It often occurs on areas that have received significant sun exposure, particularly the face, ears, scalp, neck and upper body.

A BCC may appear as:

• A pearly or shiny lump

• A pink or red patch

• A sore that repeatedly bleeds, crusts and then appears to heal

• A subtle scar-like area

• A slowly enlarging lesion

BCCs generally grow relatively slowly and very rarely spread to other parts of the body. However, this does not mean they should be ignored.

If left untreated, a BCC can continue growing into surrounding tissue and cause considerable local damage, particularly around areas such as the nose, eyelids and ears.

What is a squamous cell carcinoma (SCC)?

SCC develops from keratinocytes within the epidermis and also commonly occurs on chronically sun-exposed skin.

An SCC may look like:

• A rapidly growing lump

• A firm or tender lesion

• A scaly or crusted area

• A persistent sore

• A lesion that repeatedly bleeds

• A thickened or keratotic growth

Compared with most BCCs, SCCs can sometimes grow more quickly and have a greater potential to spread to lymph nodes or other parts of the body, although the risk varies considerably between individual tumours.

Which is more serious: BCC or SCC?

In general, SCC has a greater potential to metastasise than BCC, so certain SCCs require more urgent and sometimes more extensive management.

However, the type of cancer is only part of the story.

Risk also depends on factors such as the tumour’s size, location, histological subtype, depth, rate of growth and the patient’s immune status.

A BCC in a difficult anatomical location can therefore still be a significant clinical problem.

How are BCC and SCC diagnosed?

Appearance alone is not always enough to distinguish them.

Clinical examination and dermoscopy can provide important information, but a suspicious lesion will often require a biopsy or removal so the tissue can be examined under a microscope.

Histopathology establishes the diagnosis and provides information that can help determine the most appropriate treatment.

How are they treated?

Treatment depends on the individual tumour.

Options can include surgical excision, curettage, topical treatments, cryotherapy, photodynamic therapy or other selected treatments, depending on the type and characteristics of the lesion.

There is no single treatment that is appropriate for every BCC or SCC.

Can they be prevented?

Reducing cumulative UV exposure remains important.

Regular sunscreen use, protective clothing, hats, shade and avoiding unnecessary intense sun exposure can all reduce UV damage.

It is also worth becoming familiar with your own skin. A lesion that doesn’t heal, repeatedly bleeds, continues to grow or changes over time deserves assessment.

The key message

BCC and SCC are both common skin cancers, but they are not the same.

BCC is usually slow-growing and very rarely spreads, but can cause significant local damage. SCC can behave more aggressively and has a greater potential to spread.

Early assessment generally gives us more treatment options and can make treatment considerably simpler.

Dr Colin McTari

Skin Cancer & Dermatology