Basal Cell Carcinoma Guidelines

Updated: Feb 21, 2019
  • Author: Robert S Bader, MD; Chief Editor: William D James, MD  more...
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Guidelines

Guidelines Summary

Guidelines Contributors:  Wesley Wu, MD  Resident Physician, Department of Dermatology, Baylor College of Medicine and Mohsin R Mir, MD Director, High Risk Skin Cancer Clinic, Assistant Professor, Mohs Surgery, Laser and Cosmetic Surgery, Department of Dermatology, Baylor College of Medicine

Skin Cancer Counseling and Prevention

In 2012, the U.S. Preventive Services Task Force (USPSTF) recommended counseling children, adolescents, and young adults aged 10 to 24 years who have fair skin about minimizing their exposure to ultraviolet radiation (UVR) to reduce risk for skin cancer. [102]

In a 2011 policy statement, the American Academy of Pediatrics issued guidelines on limiting sun exposure in children. Specific recommendations for pediatricians include the following [103] :

Health-supervision practices should include advice about UVR exposure, such as avoiding sunburn and suntan, wearing clothing and hats with brims, using sunglasses, and applying sunscreen; if possible, outdoor activities should be scheduled to limit exposure to peak-intensity midday sun (10 am to 4 pm).

When a child or adolescent might sunburn, he or she should use sunscreen to reduce the known risks for sun exposure and sunburn, including the increased risk for skin cancer. Sunscreen with a sun-protection factor (SPF) of at least 15 should be applied every 2 hours and after swimming, sweating, or drying off with a towel. People may prefer to avoid sunscreens containing oxybenzone, as these may have weak estrogenic effects when absorbed through the skin.

Although all children need counseling about UVR exposure, this is particularly true for children at high risk for the development of skin cancer, including those with light skin, nevi, and/or freckling; and/or a family history of melanoma.

Skin cancer prevention is a lifelong effort, and beginning in infancy, at least one health maintenance visit per year should include advice about UVR exposure. All children are at risk for adverse effects of UVR exposure on the eyes and immune system, although not all children sunburn. Especially appropriate times for counseling about UVR exposure include during the spring and summer in northern states, before anticipated sunny vacations, and during visits for sunburns.

Because outdoor physical activity should be strongly encouraged, this should be promoted in a sun-safe manner.

Sun-protection practices tend to wane in early childhood. Beginning at age 9 or 10 years, it may be helpful for pediatricians to discuss sun protection with children, together with parents, to encourage joint responsibility for the child's sun protection.

Infants younger than 6 months should be kept out of direct sunlight and covered with protective clothing and hats. When sun avoidance is impossible, parents may apply sunscreen only on exposed areas. Absorption of sunscreen ingredients may be higher in preterm infants.

Pediatricians should become familiar with chemical photosensitizing agents. People using these oral or topical agents should limit sun exposure and avoid all ultraviolet A (UVA) light from artificial sources. When sun exposure is inevitable, they should wear fully protective clothing and high-SPF sunscreen that also blocks UVA wavelengths.

Breast-fed and formula-fed infants and other children should receive vitamin D supplementation in accordance with guidelines, for a total intake of at least 400 IU of vitamin D daily. Children at risk for hypovitaminosis D may need laboratory testing of 25-hydroxyvitamin D concentration.

Deliberate UVR exposure to artificial sources and overexposure to sun with the goal of increasing vitamin D concentrations or for other reasons should be avoided.

Pediatricians should advocate for adoption of sun-protective policies (eg, shaded playgrounds, outdoor time before 10 am, and allowing hats at schools and child care facilities).

Pediatricians should support and advocate for legislation banning use of tanning parlors by children younger than 18 years.

The American Cancer Society (ACS) advises the importance of protecting children from the sun because of the increased risk for cancer resulting from severe sunburns in childhood. [104]  For all individuals, regardless of age, the ACS recommends the following:

  • Wearing protective clothing when out in the sun

  • Wearing a hat that shades your face, neck, and ears

  • Wearing a sunscreen with an SPF of 15 or higher

  • Planning outdoor activities to avoid the midday sun

  • Wearing sunglasses to protect eyes and the tender skin around them from harmful UV rays

  • Avoiding tanning booths

Skin Cancer Screening

In 2016, the U.S. Preventive Services Task Force (USPSTF) renewed its conclusion that there is not enough evidence to recommend for or against routine screening (total body examination by a primary care doctor or patient self-examination) for early detection of skin cancers in the adult general population. [101]

The USPSTF did note the following clinical considerations:

  • Skin cancer of any type occurs more commonly in men than in women and among persons with a fair complexion, persons who use indoor tanning beds, and persons with a history of sunburns or previous skin cancer. 
  • Specific risk factors for melanoma include having an atypical mole, multiple (ie, ≥100) moles, and having a family history of melanoma.
  • The risk of melanoma increases with age; the median age at diagnosis is 63 years, and the median age at death is 69 years.
  • Clinical visual skin examination should assess skin lesions for asymmetry, border irregularity, color variability, diameter greater than 6 mm or evolution over time (ABCDE criteria)

The American Cancer Society recommends a cancer-related checkup by a physician, including a skin examination, during a periodic health examination for people age 20 years or older and monthly skin self-examination by all individuals. [105]  The Skin Cancer Foundation also recommends monthly skin self-examinations and yearly professional skin exams. [106]

Moreover, the American Academy of Dermatology (AAD) promotes free skin examinations by volunteer dermatologists for the general population through the Academy's SPOTme™ Screening Program. It also encourages regular self-examinations by individuals, such as on one’s birthday. [107]

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Diagnosis

Guidelines covering the diagnosis of basal cell skin cancer have been issued by the following organizations:

  • National Comprehensive Cancer Network (NCCN) [8]

  • European Dermatology Forum(EDF) [7]

  • German Cancer Society and the German Society of Dermatology [108]

The NCCN guidelines recommend the following workup for diagnosis of basal cell skin cancer [8] :

  • Complete skin exam to identify other pre-cancer or cancer lesions, usually located at other sun-exposed skin sites

  • Biopsy of any suspicious lesion, including the deep reticular dermis

  • Imaging studies for extensive disease with involvement of bone, perineural disease, or deep soft tissue

  • MRI is preferred over CT scan if perineural disease is suspected, because of its higher sensitivity

The German Cancer Society and the German Society of Dermatology guidelines contain the following recommendations, based on strong consensus, on the diagnosis of basal cell carcinomas (BCCs) [108] :

  • In a patient with multiple BCCs occurring before the age of 20 years, a diagnostic workup should be performed to rule out a genetic syndrome (eg, Gorlin‐Goltz syndrome, basal cell nevus syndrome, Bazex‐Dupré‐Christol syndrome, Rombo syndrome).
  • Examination of the patient without additional tools is suitable for making a suspected clinical diagnosis.
  • Following the diagnosis of BCC, a total-body skin examination should be performed or recommended.
  • Dermoscopy may contribute to improving the reliability of the clinical diagnosis of BCC.
  • Confocal laser microscopy may be useful in the diagnosis of BCC.
  • Optical coherence tomography may be useful in the diagnosis of BCC.
  • Confocal laser microscopy and optical coherence tomography may be useful in assessing the effect of topical therapies for BCC.
  • If there is clinical suspicion of osseous infiltration, CT and/or contrast‐enhanced magnetic resonance imaging (MRI) should be performed to assess the extent of intraosseous tumor spread.
  • If orbital invasion is clinically suspected, CT of the orbit should be performed to assess bone destruction, and contrast‐enhanced MRI of the orbit performed to assess intraorbital tumor spread.
  • If metastasis is clinically suspected, cross‐sectional imaging studies should be performed, and the primary histology should be reevaluated.
  • If basal cell carcinoma syndrome is suspected, imaging studies to rule out additional malignancies and to detect associated abnormalities should be done, using MRI in order to prevent radiation‐induced neoplasms.
  • The diagnosis of BCC should be confirmed by histological examination of the excised specimen following a biopsy and/or therapeutic excision, depending on the size of the tumor and the therapeutic approach. Exceptions may be made for multiple superficial tumors or in the case of basal cell carcinoma syndrome.
  • Subclinical spread can be assessed with sufficient certainty only histologically; this applies to the sclerosing subtype in particular, which is histologically characterized by fibrosis. The highest accuracy for histological detection of subclinical spread is achieved by microscopically controlled surgery.
  • During tissue processing, the potential inhomogeneity of tumors should be taken into account. If necessary, serial sections should be examined.
  • The histopathological diagnosis is performed on routine hematoxylin and eosin (H&E)–stained sections; only in rare, specific situations are special stains or immunohistology useful.
  • In addition to the diagnosis, the dermatopathology report should include information on the vertical tumor diameter (tumor thickness) and the excision margins. Moreover, the report should contain—if applicable—information about the histological subtype, in particular if there is evidence of infiltrative growth (narrow strands) and/or fibrosing/sclerosing or perineural growth.

Risk Stratification

Basal cell carcinoma rarely metastasizes and is usually not staged. The NCCN and EDF guidelines classify tumors as low or high risk, on the basis of risk factors associated with recurrence and metastasis. [8, 7]

The risk factors evaluated include the following:

  • Location
  • Size
  • Borders/clinical margins
  • Histological subtype
  • Features of aggression
  • Failure of previous treatment
  • Immunosuppression

The NCCN guidelines classify high-risk lesions by size and location, as follows [8] :

  • 2 cm or more in diameter in low-risk locations (L-area): the trunk and extremities, but not including the pretibia, hands, feet, ankles, and nail units

  • 1 cm or more in diameter in moderate-risk locations (M-area): cheeks, forehead, scalp, neck, and pretibia

  • 6 mm or more in diameter in high-risk locations (H-area): “mask area” of face (central face, eyelids, eyebrows, periorbital, nose, lips [cutaneous and vermilion], chin, mandible, preauricular and postauricular skin/sulci, temple, ear), genitalia, hands, and feet

Immunosuppression such as from antirejection therapy in organ transplant recipients and long-term use of psoralen and ultraviolet A light (PUVA) confers a higher risk of basal cell carcinoma recurrence and metastasis. Perineural involvement and previous radiotherapy are also associated with higher risk. [8]

In addition, histologically aggressive subtypes in any portion of the tumor are more likely to recur than nodular and superficial basal cell carcinomas. Histologically aggressive subtypes include the following patterns [8] :

  • Basosquamous (metatypical)
  • Micronodular
  • Infiltrative
  • Sclerosing
  • Morpheaform (desmoplastic)

Low-risk, non-aggressive subtypes include the following [8] :

  • Keratotic variant
  • Infundibulocystic variant
  • Fibroepithelioma of Pinkus
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Treatment

According to the National Comprehensive Cancer Network (NCCN) guidelines, the goal of treatment is elimination of the tumor with maximal preservation of function and physical appearance. As such, treatment decisions should be individualized according to the patient's particular risk factors and preferences. In nearly all cases, the recommended treatment modality is surgery, but patient preference may lead to choosing radiation therapy in order to achieve optimal results. [8]

Treatments vary according to cancer size, depth, and location. In select patients at high risk for multiple primary tumors, increased surveillance and prophylactic measures may be appropriate. [8]

In low-risk lesions, several options are recommended by the NCCN. Curettage and electrodessication in non–hair-bearing areas is appropriate. If lesions extend to adipose tissue, surgical excision is necessary.

A standard excision with 4 mm margins with postoperative margin assessment is also appropriate, reportedly with a higher 5-year cure rate, and should be followed by second-intention healing, linear repair, or skin grafting. Closures with significant tissue rearrangement and adjacent tissue transfer are best performed after clear margins are verified.

Radiotherapy is another potential treatment, especially for nonsurgical candidates over 60 years of age. In low-risk, superficial cancers or in cases where surgery and radiation is contraindicated or impractical, topical therapies such as 5-fluorouracil, imiquimod, photodynamic therapy (eg, aminolevulinicacid [ALA], porfimer sodium), or vigorous cryotherapy may be considered, even though the cure rate may be lower. If margins are positive, Mohs micrographic surgery (MMS) or standard re-excision of the L-area with complete circumferential, peripheral, and deep margin assessment is indicated. [8]

More aggressive treatments should be pursued for basal cell skin cancer with any high-risk feature. Comprehensive intraoperative margin control is the NCCN’s preferred treatment modality; if standard excision with postoperative margin assessment is chosen, wider surgical margins and increased recurrence rates should be expected. Radiotherapy may also be used in high-risk tumors in non-surgical candidates, but may also be used if residual disease, extensive perineural involvement, or large-nerve involvement is present. [8]

In complicated lesions where radiation and surgery have been exhausted or are impractical, the NCCN guidelines recommend multidisciplinary tumor board consultation with consideration of vismodegib or clinical trial enrollment. [8]    

In 2015, the American Society for Dermatologic Surgery (ASDS) released consensus guidelines for the treatment of basal cell carcinomas that recommended MMS as the treatment of choice for high-risk BCCs and for those in cosmetically sensitive locations. The guidelines also noted that MMS offers complete tumor margin analysis while other surgical options do not. [109]

Mohs Micrographic Surgery

In 2012, the American Academy of Dermatology in collaboration with the American College of Mohs Surgery, the American Society for Dermatologic Surgery, and the American Society for Mohs Surgery published appropriate use criteria (AUC) for Mohs micrographic surgery (MMS). The recommendations were based on the expert opinion and consensus of a rating panel of 17 Mohs surgeons and non-Mohs dermatologists. [78]

The report deemed MMS appropriate for all basal cell carcinomas—regardless of location, size, and histologic subtype—in the following:

  • Previously irradiated skin
  • Traumatic scars
  • Areas of osteomyelitis
  • Areas of chronic inflammation or ulceration
  • Patients with genetic conditions such as xeroderma pigmentosum, basal cell nevus syndrome, or other syndromes that increase risk for skin cancer

MMS was also considered appropriate for all primary and recurrent basal cell carcinomas in Area H (central face, eyelids [including inner/outer canthi], eyebrows, nose, lips [cutaneous/mucosal/vermilion], chin, ear and periauricular skin /sulci, temple, genitalia [including perineal and perianal], hands, feet, nail units, ankles, and nipples/areola).

MMS was endorsed for the following basal cell carcinomas in Area M (cheeks, forehead, scalp, neck, jawline, pretibial surface):

  • All recurrent basal cell tumors
  • Primary histologically aggressive and nodular tumors
  • Primary superficial tumors in non-immunocompromised individuals with lesions ≥0.6 cm in diameter

MMS was also deemed appropriate for the following basal cell carcinomas in Area L (trunk and extremities, excluding pretibial surface, hands, feet, nail units and ankles):

  • Recurrent histologically aggressive and nodular basal cell cancers
  • Primary, histologically aggressive tumors ≥0.6 cm
  • Primary nodular tumors >2 cm
  • Prmary nodular tumors ≥1.1 cm in immunocompromised patients

Use of MMS was considered inappropriate solely in Area L for the following [78] :

  • Recurrent superficial basal cell carcinomas
  • Primary nodular tumors ≤1 cm
  • Primary nodular tumors ≤0.5 cm in immunocompromised patients
  • Superficial basal cell carcinomas in healthy individuals
  • Superficial tumors ≤1 cm in immunocompromised patients

The NCCN prefers MMS for high-risk tumors and as adjuvant therapy if margins are positive after excision. [8]

Recurrence and metastatic disease

For complicated high-risk tumors and regional recurrence, the NCCN guidelines recommend surgery and/or radiotherapy. If these modalities are contraindicated, management by a multidisciplinary tumor board and therapy should be pursued. For metastatic disease, treatment with the Hedgehog pathway (Hh) inhibitor vismodegib or enrollment in a clinical trial is recommended. [8]  A second Hh inhibitor, sonidegib, was approved by the FDA in 2015. [100]

Follow-up and surveillance

The NCCN recommends the following measures [8] :

  • Complete skin examination every 6-12 months for life
  • Sun protection
  • Self-examination
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