Basal cell carcinoma

6 March 2019, by GUILLOT B. & BASSET-SEGUIN N.

1 - BASAL CELL CARCINOMA: THE DISEASE

Basal cell carcinoma is the commonest of the skin cancers with an incidenceof 70 new cases per 100,000 people annually in France. It generally develops after the age of 50 years old and is generally located on light exposed areas such as face and arm.

The risk factors for developing BCC are related to the factors specific to the disease and to external factors. The main disease-related risk is skin, eye and hair colour and ability to tan. The risk is greatest in people with fair skin, eyes and hair who are unable to tan. Among others, a high risk factor is exposure to sunlight, with frequent, sudden exposures being a major risk. Some rare genetic diseases are characterised by multiple BCC such as Gorlin’s syndrome and xeroderma pigmentosum. These disorders need to be treated in highly specialised centres because of their rarity.

There are several types of BCC:

— Superficial BCC, which are located particularly on the trunk and limbs, and presents as red scaling plaques with an occasionally elevated periphery.

— Nodular BCC, which are the most common and occur particularly on the face, characterised by a more or less translucent nodule with dilated blood vessels running through it, which are visible to the naked eye.

— Sclerodermiform BCC which resemble a white scar and are often very poorly delineated.

All of these forms of the disease may become pigmented or ulcerated during their course.

These different forms of the disease have specific histological appearances, to which micronodular and infiltrating forms should be added.

BCC progresses slowly. Its risk of metastasis is almost zero, although some forms of the disease which are not recognised may extend and infiltrate deeply, causing pain due to compression and haemorrhages. Once treated a patient suffering from BCC has a risk of recurrence which increases with poor prognostic indicators and when the disease has been managed late. In addition, a patient with BCC is at increased risk of developing another skin cancer during their lives.

Depending on the clinical and histological type and also on the size and site of the tumour, the 2004 French consensus conference statement has recognised three different prognostic groups in terms of the risk of recurrence. Knowledge of these prognostic groups is important to decide on choice of treatment. A biopsy of the lesion is usually performed in order to confirm the diagnosis and establish the histological type of tumour which guides the surgical approach.

2 - TREATMENT

2.1 - SURGERY

In all cases, the first line treatment is surgery, which, overall, achieves a complete recovery rate of over 95%. In the majority of cases this is performed under local anaesthesia as a single stage although extended forms of the disease or disease in areas around orifices of the face may require several operations in order to be certain that resection has been complete. The healthy tissue margins sampled around the tumour during the procedure vary depending on the group at risk from BCC. Good prognostic forms of the disease may be 3 to 4 mm rising to 1 cm in poor prognostic forms.

2.2 - LOCAL TREATMENTS

In superficial forms of the disease, local treatments such as imiquimod, 5 fluorouracil or dynamic phototherapy may be offered. These, however, are blind techniques which do not provide a certainty of completely eradicating the tumour. These methods therefor require increased follow-up.

2.3 - CRYOSURGERY

This involves destroying the tumour by freezing it. It produces good results in small superficial or nodular disease and is performed under local anaesthesia. It requires local care after treatment lasting approximately one month.

2.4 - RADIOTHERAPY

This is a second line treatment reserved for inoperable or recurrent forms of the disease and produces good curative results. It is contraindicated in genetic disease and in the sclerodermiform forms of the disease.

2.5 - SYSTEMIC TREATMENTS

These are reserved for locally advanced forms of disease which are inoperable, highly progressive or which recur on a multiple basis and even for the very rare metastatic forms of disease. Conventional chemotherapy using platinum salts or anthracycline which achieve very variable results is being used increasingly less. Currently, targeted therapies directed against a transcription pathway which is very often modified in BCC produces better results. Two molecules are currently available, vismodegib and sonidegib. These treatments are associated with occasionally severe side effects and may be responsible for embryo-foetal malformations which require a pregnancy prevention plan which must be rigorously observed. The most common side-effects are cramps, loss of appetite, alopecia and weight loss.

Currently, several clinical research trials are assessing the effectiveness of immunotherapy with the molecule anti PD-1 in locally advanced, inoperable or metastatic BCC.

3 - PREVENTION AND MONITORING

Primary prevention is based on avoidance of sunlight depending on the patient phenotype.

Monitoring of the disease with a BCC is purely clinical and involves an in definite annual review. The monitoring aims to diagnose recurrence and check for any new skin cancer.

4 - LINK

EADV leaflet published in 2019, produced by the EADV Non-Melanoma Skin Cancer Task Force:

- Basal cell carcinoma

 

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