There are two main types of skin cancer: melanoma and non-melanoma. The most common non-melanoma tumours are basal cell carcinoma and squamous cell carcinoma, which together account for 90 per cent of skin cancers. Melanoma accounts for 4 per cent of skin cancers.
In total, this report analyses 55 studies from around the world, covering nearly 13 million adults and over 56,000 cases of non-melanoma skin cancer and 27,000 cases of melanoma skin cancer.
Melanoma is the 19th most common cancer worldwide. About 232,000 new cases of skin cancer were recorded globally in 2012, accounting for 1.6 per cent of all new cases of cancer.
Non-melanoma skin cancer is not usually included in estimates for global and national cancer rates. The data on non-melanoma skin cancer is usually less accurate and less complete than for other cancers.
Lifestyle factors and skin cancer risk
In the Continuous Update Project (CUP) – the world’s largest source of scientific research on cancer prevention and survivorship through diet, nutrition and physical activity – we analyse global research on how certain lifestyle factors affect the risk of developing skin cancer. This webpage forms part of the World Cancer Research Fund/American Institute for Cancer Research Third Expert Report Diet, Nutrition, Physical Activity and Cancer: a Global Perspective.
Findings on skin cancer
There is strong evidence that:
- drinking water contaminated with arsenic INCREASES the risk of skin cancer
- being tall INCREASES the risk of malignant melanoma
- beta carotene (as high-dose supplements) has no substantial effect on the risk of non-melanoma skin cancer
There is some evidence that:
- drinking coffee might decrease the risk of malignant melanoma in women and might decrease the risk of basal cell carcinoma in men and women
- consuming alcoholic drinks might increase the risk of malignant melanoma and basal cell carcinoma
- being tall might increase the risk of basal cell carcinoma
- greater birthweight might increase the risk of malignant melanoma
Other causes of skin cancer
In addition to the findings on diet, nutrition and physical activity outlined above, other established causes of skin cancer include:
Over-exposure to certain types of light, such as ultra-violet rays from the sun or tanning devices, is the principal cause of melanoma and non-melanoma skin cancers.
Medicines used to suppress the immune system after organ transplantation are associated with increased risk of skin cancers, particularly squamous cell carcinoma.
Infection with human papilloma virus can cause squamous cell carcinomas of the skin, especially in people whose immune systems are compromised.
- occupational exposure
Exposure to specific chemicals used in the plastic and chemical industries – polychlorinated biphenyls – is strongly associated with an increased risk of skin cancer.
- family history and ethnicity
People who have a family history of melanoma may be predisposed to this type of skin cancer. Non-melanoma and melanoma skin cancer is more common in lighter-skinned populations than in darker-skinned populations due to their paler skin pigmentation.
How the research was conducted
The global scientific research on diet, nutrition, physical activity and the risk of skin cancer was systematically gathered and analysed, and then independently assessed by a panel of leading international scientists in order to draw conclusions about which of these factors increase or decrease the risk of developing skin cancer.
For a summary of the mechanisms underpinning all the findings, download the relevant chapters from the Third Expert Report:
- Exposures: Non-alcoholic drinks
- Exposures: Alcoholic drinks
- Exposures: Other dietary exposures
- Exposures: Height and birthweight
A full report bringing together all the evidence on skin cancer will be published in 2019.
This webpage is a summary.
For much more information, download the full systematic literature review.