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AlexanderSalava
SariKoskenmies

Basal Cell Carcinoma

Essentials

  • Basal cell carcinoma (BCC) is the result of uncontrolled multiplication of epidermal basal cells.
  • It is the most common malignant skin tumour in white people.
  • The malignant nature of BCC refers to the fact that it continues to grow and is able to penetrate the deeper tissues (tissue infiltration).
  • It does not normally metastasize.
  • Susceptibility to BCC depends on the amount of sun exposure over a lifetime (see also the articles on Squamous cell carcinoma Squamous Cell Carcinoma and Precancerous lesions preceding squamous cell carcinoma Precancerous Lesions Preceding Squamous Cell Carcinoma (Actinic Keratosis and Carcinoma in Situ, or Bowen's Disease)).
  • BCC can be prevented by avoiding UV exposure from the sun, e.g. by using sunscreens, protective clothing and a wide-brimmed hat.

Diagnosis

  • BCC can often be detected even clinically on the basis of typical appearance, but the diagnosis can only be confirmed by a tumour biopsy.
  • Histological types
    • Low-grade tumours, such as superficial, nodular, pigmented BCC
    • High-grade tumours, such as infiltrating, sclerosing, micronodular BCC
    • See also Table T2.
  • A superficial BCC is typically a clearly demarcated erythematous lesion with slight scaling (pictures 1 2 3).
  • A nodular BCC is typically a skin-coloured, clearly demarcated plaque or papule with a sunken centre and telangiectatic surface vessels. Nodular BCC most commonly occurs on the face (pictures 4 5 6) or the ears, whereas the superficial type is most commonly encountered on the trunk.
  • High-grade tumours may be indistinctly defined and with a scar-like appearance, but they are often clinically impossible to distinguish from low-grade tumours. The final diagnosis is histological.

Treatment Interventions for Basal Cell Carcinoma of the Skin

  • Left untreated, BCC continues to grow slowly over months and years. The speed of growth shows wide interpersonal variation. Very aggressive and fast growing types are also seen, particularly in immunosuppressed patients.
  • The recommended treatments are presented in Table T1.
  • Small basal cell carcinomas in safe skin areas can be removed in primary or outpatient health care, with follow-up at 6 to 12 months, as considered appropriate.

Surgical treatment

  • High-grade or nodular BCC should primarily be treated operatively (Table T1).
  • Surgery can also be used to treat superficial BCC, instead of using non-surgical treatment.
  • The lesion should be removed under local anaesthesia with a 3-5-mm margin of healthy tissue (clinical surgical margin, table T1). After removal, the sample shrinks and hence the histological margin reported by the pathologist is always smaller than the clinical surgical margin. If a reconstruction is required, it can be achieved with a skin flap or free skin graft.
  • If BCC was incompletely removed, either scar excision or non-surgical treatment should be used on a case-by-case basis to prevent recurrence. Mere follow-up is in these cases not acceptable.
  • Nodular and histologically high-grade BCC subtypes (sclerosing, micronodular, perineural or other infiltration) in the facial area, in particular, are usually operated on in specialized care. When occurring on the trunk or limbs, these subtypes can also be operated on in primary or outpatient care by a physician with adequate expertise.

Treatment alternatives for basal cell carcinoma according to risk classification. Source: Hernberg M, Ilmonen S, Juteau S, Jääskeläinen A-S, Koljonen V, et al. Finnish guideline for the treatment of non-melanoma skin cancers. Duodecim Publishing Company 2020.

First-line treatmentSecond-line treatmentClinical surgical marginHistological surgical margin
Superficial BCC
  • Small (head, trunk, upper and lower limbs)
Freezing1 or CO2laser, or ED in lower limbsPDT × 22 or surgical excision3 mm1 mm
  • Large or on a lower limb
PDT × 2 (freezing after due consideration)Surgical excision or treatment with ointments3 3-5 mm depending on location>1 mm
Nodular and fibroepithelioma (Pinkus tumour)Surgical excisionFreezing after due consideration3 mm1 mm
High-grade BCCSurgical excisionPostsurgical or adjuvant radiotherapy, as necessary4-5 mm depending on location2-5 mm
Perineural infiltrationSurgical excisionPostsurgical or adjuvant radiotherapy, as necessaryHASH(0x2ed5390) 5 mmHASH(0x2ed5390) 3 mm
1 To be used by a physician with adequate expertise in the technique, using it for long enough for the margins to thaw in 1 min.
2 PDT twice at an interval of 1-2 weeks. Photosensitizing methyl aminolevulinate ointment is applied to the skin. After letting the ointment work for 3 h, the area is subjected to red light (wavelength 630 nm) for about 8 min. The ointment and the light work together to cause a chemical reaction leading to the destruction of tumour cells.
3 Imiquimod (5%) five days a week for 4-6 weeks, until a crust reaction occurs, or fluorouracil (5%, may require special permit) twice daily for 3-4 weeks until crust reaction.
CO2 = carbon dioxide; ED = electrodessication (electric peeling); PDT = photodynamic or light activation treatment
Non-surgical treatments
  • See Table T1.
  • Small superficial BCCs (e.g. < 0.5 cm on the face, < 1.5 cm on the trunk or upper limbs) can be treated with liquid nitrogen by a physician with adequate expertise in the technique (picture 8).
  • On lower limbs, cryotherapy of BCC is usually avoided due to the risk of leg ulcer.
  • For nodular BCC, surgery is the first-line option but freezing can also be used (image series 9, video Intense Cryotherapy of Superficial Basal Cell Carcinoma on the Back - Video), as considered appropriate. A light scar will remain.
  • Other non-surgical treatments for superficial BCC include photodynamic treatment (PDT) and treatment with imiquimod ointment.

Follow-up and risk of recurrence

  • No follow-up is needed for low-risk BCC removed with sufficient histological margins.
  • For high-grade or non-surgically treated BCC, follow-up should be planned in the treating unit, as considered appropriate.
  • About 1 in 3 patients with BCC will develop one or more BCCs over the next 3 years.
  • Classification of BCC according to the risk of recurrence (table T2)

Classification of BCC according to the risk of recurrence. Source: Hernberg M, Ilmonen S, Juteau S, Jääskeläinen A-S, Koljonen V, et al. Finnish guideline for the treatment of non-melanoma skin cancers. Duodecim Publishing Company 2020.

FindingsLow risk of recurrenceHigh risk of recurrence
Histological type of growth
  • Superficial, fibroepithelioma or Pinkus tumour
  • Nodular
  • Pigmented
  • Influndibular cystic
Invasive e.g.
  • Infiltrating
  • Sclerosing growth (morpheaform)
  • Micronodular
  • Basosquamous
  • Sarcomatoid
  • Perineural invasion
Size of tumour
  • <2 cm on body and limbs (excluding hands, nails, tibial surface, ankle, feet -> high risk of recurrence)
  • <1 cm cheeks, forehead, scalp, neck, tibial surface
  • >2 cm body and limbs
  • >1 cm cheeks, forehead, scalp, neck, tibial surface
  • Nose, eyelids, lips, temple, ear (so-called H-zone)
Recurrence of tumourPrimaryRecurrent, previously irradiated area, immunosuppressed patient

Specialist consultation

  • BCCs in difficult to treat areas, and high-grade BCCs, e.g. in the vicinity of eyelids, nostrils and ear canals.

    References

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    • Mirali S, Tang E, Drucker AM, et al. Follow-up of Patients With Keratinocyte Carcinoma: A Systematic Review of Clinical Practice Guidelines. JAMA Dermatol 2023;159(1):87-94 [PubMed]
    • Patel PV, Pixley JN, Dibble HS, et al. Recommendations for Cost-Conscious Treatment of Basal Cell Carcinoma. Dermatol Ther (Heidelb) 2023;13(9):1959-1971 [PubMed]
    • Sanclemente G, Aguirre DC, Thomson J. Interventions for Basal Cell Carcinoma: Summary of Main Comparisons From a Cochrane Review and a Practical Interpretation of Findings. Actas Dermosifiliogr 2023;114(1):39-48 [PubMed]
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    • Najmi M, Sivesind TE, Thomson J, et al. From the Cochrane Library: Interventions for basal cell carcinoma of the skin. J Am Acad Dermatol 2021;85(6):e417-e418 [PubMed]
    • Firnhaber JM. Basal Cell and Cutaneous Squamous Cell Carcinomas: Diagnosis and Treatment. Am Fam Physician 2020;102(6):339-346 [PubMed]
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    • Fukumoto T, Fukumoto R, Oka M, et al. Comparing treatments for basal cell carcinoma in terms of long-term treatment-failure: a network meta-analysis. J Eur Acad Dermatol Venereol 2019;33(11):2050-2057 [PubMed]
    • Tchanque-Fossuo CN, Eisen DB. A systematic review on the use of cryotherapy versus other treatments for basal cell carcinoma. Dermatol Online J 2018;24(11): [PubMed]
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