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Writer's pictureAmit Goyal

Understanding the Stages of Basal Cell Carcinoma: A Comprehensive Guide by Dr. Goyal, Founder of mySkinDoc

Updated: Oct 20



Picture of a nodular basal cell carcinoma
nodular basal cell carcinoma

As a dermatologist and founder of mySkinDoc, I see patients regularly who are concerned about suspicious growths on their skin. Basal cell carcinoma (BCC), the most common type of skin cancer, often comes up in our discussions. One of the most frequently asked questions is about the stages of basal cell carcinoma and what they mean for treatment and prognosis. Today, I’ll take you through these stages, explaining the key details to help you better understand this condition.


What is Basal Cell Carcinoma?


Basal cell carcinoma arises from the basal cells in the epidermis—the outermost layer of skin. These cells are responsible for producing new skin cells as old ones die off. BCC typically develops in areas exposed to the sun, such as the face, neck, and arms, but can occur elsewhere as well. Unlike other skin cancers, BCC rarely spreads (metastasizes) to other parts of the body, but if left untreated, it can grow deeper into surrounding tissues and cause significant damage.


Staging Basal Cell Carcinoma


Understanding the stages of basal cell carcinoma can help both patients and healthcare providers determine the most appropriate treatment plan. Although BCC is usually slow-growing and does not metastasize, early detection is key to ensuring that it can be treated effectively.


Stage 0: Carcinoma in Situ


At this stage, the cancer is non-invasive and remains in the upper layer of the skin (epidermis). It hasn’t yet penetrated the deeper layers or spread to surrounding tissues. This stage is also referred to as carcinoma in situ, meaning the cancerous cells are in their original location and haven’t started to invade nearby structures. While this stage is the earliest form of BCC, it’s crucial to treat it promptly to prevent it from advancing.


Stage I: Localized Basal Cell Carcinoma


Stage I BCC refers to tumors that are no larger than 2 centimeters (about ¾ of an inch) in diameter. At this point, the cancer may have started to invade deeper layers of the skin but hasn’t spread beyond the primary site. The good news is that treatment at this stage is highly successful. Options may include surgical removal, such as excision or Mohs micrographic surgery, or non-invasive treatments like cryotherapy or topical medications, depending on the size and location of the tumor.


Stage II: Larger Tumors, No Spread


Stage II BCC involves larger tumors—those greater than 2 centimeters—but the cancer has not yet spread to nearby lymph nodes or other tissues. While still confined to the original site, the tumor may have begun to grow deeper into the skin or underlying tissues. Treatment at this stage may require more aggressive intervention, such as surgery combined with radiation or advanced topical treatments. The prognosis remains positive, especially if the cancer is caught early in this stage.


Stage III: Locally Advanced Basal Cell Carcinoma


In Stage III, basal cell carcinoma has spread to nearby tissues, such as bone, muscle, or cartilage, but has not yet reached distant sites. This is known as locally advanced basal cell carcinoma. While BCC doesn’t usually metastasize, tumors that grow unchecked can cause significant local damage. For example, if the cancer is on the face, it can erode nearby structures like the nose, ears, or eyes. Treatment for Stage III BCC often involves surgery, possibly followed by radiation therapy or targeted drug therapy to help reduce the risk of recurrence.


Stage IV: Metastatic Basal Cell Carcinoma


Though extremely rare, basal cell carcinoma can metastasize to distant sites such as the lungs or lymph nodes. When this happens, it’s classified as Stage IV. In this stage, the tumor has spread beyond its original site and invaded distant organs. Treatment for metastatic BCC may involve a combination of surgery, radiation, and systemic therapies such as targeted treatments or immunotherapy. While this is the most serious form of BCC, recent advances in treatment options have provided new hope for patients with advanced or metastatic disease.


Factors Affecting Staging of Basal Cell Carcinoma


It’s important to note that staging for basal cell carcinoma is not as commonly used as it is for other cancers. In many cases, BCCs are detected and treated long before they progress through the stages described above. However, when the cancer is more aggressive, several factors influence its stage:


Tumour Size

Larger tumors are more likely to be classified in higher stages.


Depth of Invasion

How deeply the cancer has penetrated into the skin and surrounding tissues is a key factor in determining its stage.


Histological Features

Certain subtypes of BCC, such as infiltrative or morpheaform BCC, are more likely to invade deeper tissues, affecting the stage and treatment plan.

• Perineural Invasion: When cancer cells invade the nerves, the risk of the cancer spreading or recurring increases, often placing the BCC in a higher stage.

• Location: Tumors in high-risk areas like the face or scalp may be staged higher due to their proximity to vital structures.


Early Detection is Key


At mySkinDoc, we emphasize the importance of early detection and treatment. Because basal cell carcinoma often develops slowly and initially causes little or no discomfort, it can go unnoticed. Look out for persistent open sores, reddish patches, shiny bumps, or scars that don’t seem to heal. If you notice any of these symptoms, I encourage you to book a remote consultation with

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