Basal cell carcinomas are slow-growing cancers. They typically appear as elevated or flat lesions present on the sun-exposed parts of the body such as the face, scalp, chin, neck or back.

The lesions are more common in fair-skinned and blond or red-haired individuals and are therefore common among those of European ancestry. Those with albinism are also at a greater risk of developing basal cell carcinomas (albinism refers to genetic absence of all pigment producing melanin in the body). Individuals of African or South Asian descent with dark skin colour are highly resistant to skin cancer, including basal cell cancer.

After an organ transplant, the susceptibility to basal cell cancers rises. Among those of European ancestry, the risk for basal cell carcinoma is increased ten-fold compared with individuals with a similar sun exposure who have not had an organ transplant. By contrast, among East Asian patient, incidence of the tumors is extremely low, even after organ transplant.

Basal cell carcinoma is slightly more common in men than in women, possibly due to an increased likelihood of outdoor work and therefore greater sun exposure among men. The incidence among women, however, has been on the rise over the past few decades, which could be attributable to an increase in the use of sun beds or due to an increased tendency to seek early medical attention and diagnosis.

Basal cell carcinoma is also more common among individuals over the age of 50. However, the number of younger people being diagnosed with the condition is increasing, mainly due to the rising popularity of sun beds for cosmetic tanning.

Pathology

Basal cell carcinoma is highly localized and does not usually spread. However, as this type of cancer can still invade and destroy surrounding tissue, it is considered a malignant form of cancer.

Individuals who develop a single lesion of basal cell carcinoma are at an increased risk of developing additional lesions. According to estimates, the risk of developing additional lesions within 3 years is 44%.

Genetics

A rare hereditary disorder called basal-cell nevus syndrome (BCNS) raises the risk of developing basal cell carcinoma. Also known of as Gorlin syndrome, BCNS is associated with mutations of genes located at human chromosome 9q22. A tumor suppressor gene PTCH1 has also been identified. If mutations occur in this gene, cell signalling pathways may fail to prevent cancerous growth of the cell.

Basal cell carcinoma localization

Basal cell cancers are limited in their growth and very rarely spread to other organs. Therefore, their careful excision by surgery results in 100% cure-rates. According to researchers, basal cell cancers are also genetically stable which prevents further DNA mutation leading to metastasis.