Basal Cell Carcinoma

A common occurrence in primary care is the “oh by the way” comment.

Many times as my hand is on the door, at the end of the visit, my patients often ask if I can quickly “look at” a skin lesion. For the new practitioner and even the seasoned practitioner, it can be very difficult to decide within just a moment or so, whether a skin lesion is benign, or cause for concern.

With the weather warming and patients venturing out in the sun, the spring and summer time is a great time for oh by the way comments regarding skin lesions, or visits dedicated entirely to the discussion of a lesion that is changing or concerning to the patient.

Today, we will give a comprehensive review of basal cell carcinoma. Look for another article over the summer focused on squamous cell carcinoma and melanoma!

 

How Common is it?

Basal cell carcinoma is the least dangerous, yet most common type of skin cancer. Although the exact number of cases per year is unknown, it is estimated that up to 80% of new diagnoses of skin cancers are basal cell carcinomas.

The term is given to this type of cancer because it arises from the basal cell layer of the skin (Domino, 2016).  It is the least dangerous skin cancer because it has a very rare potential for metastasis but does cause local tissue destruction.

Unfortunately, the incidence of basal cell cancers in the United States is rising rapidly.  One study indicates there is a 10% increase in the number of basal cell skin cancers each year and the lifetime risk for the patient to develop basal cell skin cancer is 30% (Wu, 2019). 

The incidence of basal cell skin cancer in patients age 55-75 is 100 times the incidence in patients who are less than age 20.

Risk factors for basal cell carcinoma (BCC) include UV light exposure via sunlight (most important).

The frequency, timing and duration of sun exposure should be questioned during the patient’s history. It is most common in patients with light skin, Caucasians, and those who tend to sunburn easily. Males are 30% more likely to have a BCC than females.

Interestingly, states such as Hawaii and California have an almost doubled incidence of BCC than midwestern states (Wu, 2019). Family history of skin cancer, chronic immunosuppression, and previous radiation or arsenic exposure are also risk factors.

Tanning beds represent a unique risk for skin cancer, particularly basal cell carcinoma. Frequent use (more than 6 times per year) has been shown to increase the incidence of BCC. Tanning beds, although may be overlooked, are an important factor in the development of skin cancer.

 

The Skin Exam

Patients may come in requesting a yearly skin examination or may have a specific mole or lesion they would like the practitioner to examine. Many basal cell carcinomas (80% or so) will present on the face and neck, while 20% typically present on the trunk, back, or lower limbs.

It is important to know that there are different types of basal cell carcinomas, including nodular, superficial, and morpheaform.

The most common form of BCC is nodular, which presents as a pearly pink papule or plaque, sometimes with telangiectasia, typically on the face.

For the students out there, the bolded text is a very typical board type presentation in a question stem.

Superficial can present as lighter, red, scaly papules with an atrophic center (Domino, 2016). Morpheaform can present as firm, smooth, flesh colored scar like papule (Domino, 2016).

 

One of the main concerns is to differentiate between other more concerning lesions, such as a squamous cell carcinoma or a melanoma. The general impression and suspicion is performed by the practitioner and dermatopathology can make the diagnosis if a biopsy or excision is performed.

 

Do We Biopsy?

Once a skin exam is performed by the practitioner, the decision needs to made as to whether a biopsy or excision needs to be completed. Depending on the practitioner’s level of comfort, this may be performed in the office, or by a more experienced dermatologist.

In my practice, I will excise suspicious lesions on the back, trunk, or arms, but typically refer lesions on the face to dermatology or plastic surgery.

As discussed above, the definitive treatment for basal cell carcinoma is usually surgical excision.  Other methods that are available include 5-fluorouracil cream which can decrease DNA synthesis in low risk areas.  This is typically used for 3-10 weeks.  Imiquimod is also used in low risk BCC, with up to a 90% cure rate (Domino, 2016).

For patients with concern for significant cosmetic problems based on the location of the lesion, a professional with good experience is typically warranted, such as a plastic surgeon. High risk areas include the nasal bridge, philtrum, lip, temple and face (Domino, 2016). Mohs surgery can be performed for lesions in high risk areas, recurrent lesions, or aggressive growth pattern.

Once a lesion is removed, pathology can confirm the presence or absence of a basal cell carcinoma. Once it has been confirmed, margins should be confirmed by pathology to affirm that the entire lesion has been removed. Good care to watch for signs and symptoms of infection after a biopsy is important as well.

 

Preventing Basal Cell Carcinoma

General prevention measures are important to prevent both an initial episode of BCC as well as recurrence. Unfortunately, up to 36% of patients will experience a recurrence, particularly if there is a large history of sun exposure. Routine skin checks by a dermatologist are important to identify possible early recurrences and be proactive.

The most obvious of the prevention methods includes avoiding sunlight. This may seem obvious, but in my practice, I am surprised by how many of my patients, despite working in professions outdoors, do not wear any amount of sunscreen…ever. Broad spectrum sunscreen of at least 30 to 50 spf, reapplied every few hours is key. Patients should be reminded that if the skin gets wet or they are sweating excessively, sunscreen should be reapplied more often. Some sunscreens boast up to 100 spf (sun protection factor).  Patient should be counseled to avoid overexposure to the sun by staying indoors during the period of time between 10 am and 4 pm (Domino 2016). Tanning should obviously be avoided. Hats, long sleeves should be worn during peak hours and when the sun is active.

Basal cell carcinoma remains in important preventable skin cancer that is prevalent throughout the United States and continues to rise in prevalence due to lack of sunscreen and continued sun exposure by patients.  Family practice providers should provide education in regards to sun exposure and perform regular skin checks on patients. 

Patients should be empowered to monitor skin for changing lesions and alert clinicians.

 

References

Domino, Frank (2016). Basal Cell Carincoma. The Five-Minute Clinical Consult, Wolters Kluwer.

Wu, Peggy (2019). Epidemiology, Pathogenesis, and clinical features, of basal cell carcinoma. UpToDate. Date of access 30 April 2019.

Young, Antony and Tewari, Angela (2019). Sunburn. UpToDate. Date of Access 30 April 2019.