Patients with a history of non-melanoma skin cancer are up to 26% more likely to develop further cancers, according to researchers from Harvard Medical School in Boston, Massachusetts.
Although non-melanoma skin cancers such as basal cell carcinomas and squamous cell carcinomas are rarely fatal, the findings suggest patients with these conditions have an additional risk of melanoma, breast and lung cancers.
The study followed 153,576 middle-aged men and women from two US studies of the health of healthcare workers over 24 years. These patients developed 36,102 new cases of non-melanoma skin cancers and 29,447 new cases of other cancers.
Researchers compared incidences and found men had a 15% greater risk of a second cancer if they had a history of non-melanoma skin cancer. For women, the risk was 26%.
These men were at twice the risk of melanoma skin cancer than those who had not had non-melanoma skin cancer. For women, the risks of breast cancer rose by 19%, lung cancer by 32%, and melanoma by 158%.
Study authors said the increased risk of melanoma in these patients is likely due to sun exposure. For other cancers, ‘certain genetic markers underlying skin cancer are also associated with other cancer types’, researchers said.
They said biological mechanisms that protect against cell damage, such as DNA repair or immune responses, ‘may act systemically and play a role in cutaneous and internal carcinogenesis’.