Basal cell carcinoma-treatments for the commonest skin cancer

Abstract

Background: With an incidence of 70 to over 800 new cases per 100 000 persons per year, basal cell carcinoma (BCC) is a very common disease, accounting for about 80% of all cases of non-melanoma skin cancer. It very rarely metastasizes. A variety of treatments are available for the different subtypes and stages of BCC.

Method: This review is based on pertinent literature retrieved by a selective search in the Medline database, as well as the American Cancer Society guidelines on BCC and the German guidelines on BCC and skin cancer prevention.

Results: The gold standard of treatment is surgical excision with histological control of excision margins, which has a 5-year recurrence rate of less than 3% on the face. For superficial BCC, approved medications such as imiquimod (total remission rate, 82-90%) and topical 5-fluorouracil (80%) are available, as is photodynamic therapy (71-87%). Other ablative methods (laser, cryosurgery) are applicable in some cases. Radiotherapy is an alternative treatment for invasive, inoperable BCC, with 5-year tumor control rates of 89-96%. Recently, drugs that inhibit an intracellular signaling pathway have become available for the treatment of locally advanced or metastatic BCC. Phase I and II clinical trials revealed that vismodegib was associated with objective response rates of 30-55% and tumor control rates of 80-90%. This drug was approved on the basis of a non-randomized trial with no control arm. It has side effects ranging from muscle cramps (71%) and hair loss (65%) to taste disturbances (55%) and birth defects.

Conclusion: The established, standard treatments are generally highly effective. Vismodegib is a newly approved treatment option for locally advanced BCC that is not amenable to either surgery or radiotherapy.

Figure 1

Superficial-multicentric basal cell carcinoma in the axilla, a) before and b) after photodynamic therapy

Figure 2

Hedgehog signal pathway. While the hedgehog signal pathway is important in embryogenesis, it is usually inactivated in adult cells. The figure shows mutations (red border) which can lead to the activation of the hedgehog pathway in a basal cell carcinoma and inhibitors (gray border) which can block the pathway. PTCH, patched; SMO, smoothened; SHH, sonic hedgehog; SUFU, suppressor of fused; Gli, Gli transcription factors (modified from [27])

Figure 3

Sporadic solitary locally advanced basal cell carcinoma on the scalp of an 89-year-old woman a) before and b) after 10 weeks of therapy with the hedgehog signal pathway inhibitor vismodegib. Multiple BCC on back of a 62-year-old man with nevoid BCC syndrome c) before and d) after 8 months of therapy with the hedgehog signal pathway inhibitor LDE225. His seborrheic keratoses did not change during therapy.