Basal Cell Carcinoma Guidelines

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. ^[104]

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 ^[105] :

• 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. ^[106]  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. ^[103]

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. ^[107]  The Skin Cancer Foundation also recommends monthly skin self-examinations and yearly professional skin exams. ^[108]

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. ^[109] The AAD also encourages regular self-examination by individuals, such as on one’s birthday.

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

• National Comprehensive Cancer Network (NCCN) ^[7]
• American Academy of Dermatology (AAD) ^[110]
• European Dermatology Forum(EDF) ^[6]
• German Cancer Society and the German Society of Dermatology ^[111]

The NCCN guidelines recommend the following workup for diagnosis of basal cell skin cancer ^[7] :

• 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 AAD guidelines recommend the following biopsy techniques for basal cell carcinoma (BCC) ^[110] :

• Punch biopsy
• Shave biopsy
• Excisional biopsy

AAD recommendations regarding biopsy are as follows:

• The biopsy technique chosen will depend on the characteristics of the suspected malignancy (eg, morphology, location) and the judgment of the physician.
• The biopsy specimen size and depth should be adequate to provide the recommended clinical information and pathology report elements to permit accurate diagnosis and guide therapy.
• Repeat biopsy may be considered if initial biopsy specimen is inadequate for accurate diagnosis.

In cases of suspected BCC, the AAD guidelines strongly recommend providing the following clinical information when sending a biopsy specimen to the pathologist:

• Patient age and sex
• Anatomic location of the specimen
• Whether the lesion is recurrent

   Providing the following information is recommended:

• Size of lesion
• Immunosuppression
• History (especially radiation burn, organ transplant)

   On the final pathology report (on excision specimens), inclusion of the following information is recommended:

• Histologic subtype
• Invasion beyond reticular dermis
• Perineural involvement

The German Cancer Society and the German Society of Dermatology guidelines contain the following recommendations, based on strong consensus, on the diagnosis of BCCs ^[111] :

• 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. ^{[7, 6]}

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 ^[7] :

• 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. ^[7]

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 ^[7] :

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

Low-risk, non-aggressive subtypes include the following ^[7] :

• Keratotic variant
• Infundibulocystic variant
• Fibroepithelioma of Pinkus

According to the National Comprehensive Cancer Network (NCCN) guidelines, the goal of treatment of basal cell carcinomas (BCCs) 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. ^[7]

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. ^[7]

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.Tissue rearrangement (eg, flap reconstruction, extensive undermining) should not be undertaken until clear margins are identified. Second-intention healing, linear repair, or skin graft are acceptable modalities.

Radiotherapy is another potential treatment, especially for nonsurgical candidates over 60 years of age. In superficial cancers, topical therapies such as 5-fluorouracil, imiquimod, photodynamic therapy (eg, aminolevulinicacid [ALA], porfimer sodium), or cryotherapy may be considered, even though the cure rate may be lower. If margins are positive, treatment options include Mohs micrographic surgery (MMS); other forms of peripheral and deep en face margin assessment (PDEMA); or re-excision, if clinically feasible. ^[7]

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. ^[7]

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. ^[7]    

The American Academy of Dermatology (AAD) guidelines include the following recommendations for surgical treatment ^[110] :

• The treatment plan should consider recurrence rate, preservation of function, patient expectations, and potential adverse effects.
• Curettage and electrodessication (C&E) may be considered for low-risk tumors in non–terminal hair–bearing locations.
• For low-risk primary BCC, surgical excision with 4-mm clinical margins and histologic margin assessment is recommended.
• Standard excision may be considered for select high-risk tumors. However, strong caution is advised when selecting a treatment modality without complete margin assessment for high-risk tumors.
• MMS is recommended for high-risk BCC.

AAD recommendations for non-surgical treatment are as follows ^[110] :

• Cryosurgery may be considered for low-risk BCC when more effective therapies are contraindicated or impractical.
• If surgical therapy is not feasible or preferred, topical therapy (eg, imiquimod or 5-fluorouracil), photodynamic therapy with aminolevulinic acid (ALA) or methyl aminolevulinate (MAL), and radiation therapy (eg, superficial radiation therapy, brachytherapy, external electron beam, and other traditional radiotherapy forms for BCC) can be considered when tumors are low risk, with the understanding that the cure rate may be lower.
• Adjustment of topical therapy dosing regimen on the basis of side effect tolerance is recommended.
• There is insufficient evidence to recommend the routine use of laser or electronic surface brachytherapy in the treatment of BCC.

In 2015, the American Society for Dermatologic Surgery (ASDS) released consensus guidelines for the treatment of BCCs 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. ^[112]

Updated guidelines on the management of BCC in adults, published by the British Association of Dermatologists (BAD) in 2021, include the following recommendations for surgical treatment ^[113] :

• Offer standard surgical excision as a first-line treatment to adults with low-risk BCC.
• Offer standard surgical excision with immediate reconstruction as a first-line treatment option to adults with primary BCC with a high-risk factor, if the BCC has well-defined clinical margins under bright lighting and magnification or dermoscopy.
• Offer standard surgical excision with delayed definitive reconstruction, or Mohs micrographic surgery, as the first-line treatment option to adults with high-risk BCC in a high-risk anatomical site if the BCC has poorly defined clinical margins under bright lighting and magnification or dermoscopy.
• For excision, recommended peripheral clinical surgical margins are 4 mm for low-risk BCC and at least 5 mm for primary BCC with a high-risk factor.
• Ensure adequate excision at the deep margin to a clear plane, including a fat layer where present, and other deeper structures if needed.
• Consider Mohs micrographic surgery in adults with primary BCC with at least one high-risk factor, or with advanced BCC. Offer it as a first-line treatment to adults with recurrent BCC with at least one other high-risk factor, especially if the tumor is at a high-risk site.
• In adults with recurrent BCC with at least one other high-risk factor, consider standard surgical excision with at least a 5 mm margin and delayed definitive reconstruction.

For systemic therapy, the BAD guidelines recommend offering vismodegib, if available, to adults with advanced BCC who are unsuitable for Mohs micrographic surgery, standard surgical excision, or radiotherapy, including patients with Gorlin syndrome, following multidisciplinary team discussion.

The BAD guidelines recommend offering radiotherapy as an option to adults (suggested age ≥ 60 years) with low-risk or high-risk BCC who are iunsuitable for or decline Mohs micrographic surgery or standard surgical excision and who express a preference for radiotherapy, and in whom the lesion is a nodular BCC; an infiltrative subtype of BCC, provided a sufficient planning margin is used; or an excised BCC with involved margins. ^[113]

The BAD guidelines recommend against offering radiotherapy for recurrent BCC following previous radiotherapy, or for lesions associated with certain genetic syndromes predisposing to skin cancers, for example Gorlin syndrome or xeroderma pigmentosum. Treatment alternatives should be discussed in a multidisciplinary team meeting. The BAD guidelines recommend against routinely offering radiotherapy for a BCC that is on an area of poor blood supply (eg, the lower limbs); in a younger patient (suggested age < 60 years), in whom the late effects of radiotherapy could be an issue; or invading bone or cartilage. ^[113]

In adult patients with low-risk BCC who are unsuitable for or decline standard surgical excision, BAD guidelines recommend offering the following as options:

• Topical imiquimod
• Topical 5-fluorouracil
• Cryosurgery
• Topical photodynamic therapy

In adults with excised high-risk BCC with an involved histological margin, BAD guidelines recommend offering further standard surgical re-excision, if not contraindicated, after multidisciplinary team discussion. The BAD guidelines recommend referring all adults with excised high-risk BCC with a close histological margin (< 1 mm) for multidisciplinary team discussion of management options, which may include surgical re-excision, Mohs micrographic surgery, radiotherapy, or monitoring. ^[113]

BAD recommendations for follow-up include the following:

• Do not routinely offer follow-up to patients with adequately treated isolated BCC, unless for a postoperative review.
• Offer, if possible, at least yearly follow-up to adults with a history of multiple BCCs who are likely to develop further tumors or recurrence within 12 months.

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. ^[79]

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 BCCs 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 BCCs 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 BCCs 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 ^[79] :

• Recurrent superficial BCCs
• Primary nodular tumors ≤1 cm
• Primary nodular tumors ≤0.5 cm in immunocompromised patients
• Superficial BCCs 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. ^[7]

Recurrence and metastatic disease

For recurrent or advanced disease that is local, the NCCN guidelines recommend following primary treatment pathways. For nodal or distant metastases, the NCCN recommends multidisciplinary consultation to consider one or more of the following options:

• Hedgehog (Hh) pathway inhibitor treatment with vismodegib; a second Hh inhibitor, sonidegib, was approved by the FDA in 2015, but not for metastatic disease, so the NCCN rates it as category 2B
• Surgery
• Radiation therapy
• Clinical trial enrollment

AAD guidelines include the following recommendations for managing locally advanced or metastatic BCC ^[110] :

• Multidisciplinary consultation and smoothened inhibitors (eg, vismodegib) are recommended for patients with metastatic BCC.
• If treatment of metastatic BCC with smoothened inhibitors is not feasible, platinum-based chemotherapy or best supportive care is recommended.
• If surgery and radiation therapy are contraindicated or inappropriate for the treatment of locally advanced BCC, or if residual tumor persists following surgery and/or radiation therapy and further surgery and radiation therapy are contraindicated or inappropriate, systemic therapy with a smoothened inhibitor should be considered.
• Patients with advanced disease should be provided with or referred for best supportive and palliative care, to optimize symptom management and maximize quality of life.

Radiation therapy

In 2020, the American Society for Radiation Oncology published clinical practice guidelines on definitive and postoperative radiation therapy (RT) for basal and squamous cell cancers of the skin. ^[114] Recommendations regarding definitive radiation therapy for BCC are as follows:

• RT is recommended as curative treatment in patients with BCC who cannot undergo or who decline surgical resection.
• RT is conditionally recommended as curative treatment in patients with BCC in anatomic locations where surgery can endanger function or cosmesis.
• RT is conditionally not recommended for patients with BCC who have genetic diseases that predispose to increased radiosensitivity.

Postoperative RT is recommended in cases of gross perineural spread that is apparent clinically or radiologically. Postoperative RT is conditionally recommended in the following clinical scenarios:

• BCC with narrow or positive margins that is refractory to further surgical correction owing to morbidity or adverse cosmetic outcome
• BCC associated with recurrence after a previous margin-negative resection
• BCC associated with locally advanced or neglected tumors that involve bone or those infiltrating muscle

Recommendations for cutaneous BCC that has metastasized to clinically apparent regional lymph nodes are as follows:

• Therapeutic lymphadenectomy followed by adjuvant RT (Exception: Patients with a single, small (< 3 cm) cancerous cervical lymph node, without extracapsular extension)
• Definitive RT only recommended if patient is medically inoperable or surgically unresectable

Conditional recommendations for cutaneous BCC in patients who are at high risk of regional nodal metastasis are as follows:

• Imaging and sentinel lymph node biopsy, in order to guide the need for and target of lymph node basin RT
• If tumor thickness is greater than 6 mm, elective lymph node basin RT only in patients undergoing RT on the primary site, with overlap of the adjacent nodal basin

The recommended radiation dose for patients with cutaneous BCC who are undergoing adjuvant RT after therapeutic lymphadenectomy is 6000-6600 cGy (conventional fractionation [180-200 cGy/fx]).

Recommended radiation techniques/dose-fractionation schedules for patients with BCC who are receiving RT in a definitive setting are as follows:

• Conventional (180-200 cGy/fx): BED10 (biologically effective dose assuming an α/β = 10) 70-93.5 (delivered 5 days/wk)
• Hypofractionation (210-500 cGy/fx): BED10 56-88 (delivered daily or 2-4 times/wk)

Recommended dose-fractionation schedules for patients with BCC who are receiving RT in a postoperative setting are as follows:

• Conventional (180-200 cGy/fx): BED10 59.5-79.2 (delivered 5 days/wk)
• Hypofractionation (210-500 cGy/fx): BED10 56-70.2 (delivered daily or 2-4 times/wk)

Follow-up and surveillance

The NCCN recommends the following measures ^[7] :

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

AAD recommendations for the follow-up of BCC and reduction of risk for future skin cancer are as follows ^[110] :

• After diagnosis of a first BCC, skin cancer screening for new keratinocyte cancers (BCC or cutaneous squamous cell carcinoma) and for melanoma should be performed on at least an annual basis.
• Patients with a history of BCC should be counseled on skin self-examination and sun protection.
• The use of topical and oral retinoids (eg, tretinoin, retinol, acitretin, isotretinoin) is not recommended to reduce the incidence of future keratinocyte cancers in those with a history of BCC.
• Dietary supplementation of selenium and β-carotene is not recommended to reduce the incidence of future keratinocyte cancers in those with a history of BCC.
• There is insufficient evidence to make a recommendation on the use of oral nicotinamide, α-difluoromethylornithine (DFMO), or celecoxib in the chemoprevention of BCC.