Does endometriosis increase skin cancer risk?

Endometriosis has been associated with an increased risk of skin cancer, particularly melanoma.

Key Points

Highlights:

• This is the largest and most comprehensive study of endometriosis and skin cancer to date.
• Results show an association between endometriosis and skin cancer risk, which was more robust for melanoma type of skin cancer.

Importance:

• This study confirms a positive association between endometriosis and risk of skin cancer in the largest cohort of women and suggests several potential mediators for this partnership.

What’s done here?

• The association between endometriosis and the risk of three main types of skin cancer – basal cell carcinoma, squamous cell carcinoma, and cutaneous melanoma, was studied in a large cohort of women (98,995 French women aged 40-65 years) with 21 years of complete follow-up.

Key results:

• Endometriosis was associated with a higher skin cancer risk, primarily with melanoma.
• Women with a family history of skin cancer were at increased endometriosis risk.

Limitations of the study:

• Endometriosis history was based on self-reporting, which may have resulted in misclassification.
• No data was collected on stage, type, and severity of endometriosis.

Lay Summary

Two major types of skin cancer are melanoma, which is the least frequent type but with highest metastatic potential; and non-melanoma skin cancers which include basal cell carcinoma and squamous cell carcinoma. Several risk factors are identified for skin cancer – sun exposure, family history of skin cancer, genetics, etc. Recent studies also suggested that a history of endometriosis increases the risk of melanoma skin cancer. Farland and colleagues extend these studies to examine the association between endometriosis and the risk of all three above types of skin cancer in a huge sample of women – 98,995 French women aged 40-65. Their results revealed that endometriosis is associated with increased risk of all skin cancers; however, the association was stronger for melanoma type of skin cancer. For non-melanoma skin cancer, endometriosis was found to be associated with only the basal cell carcinoma risk among women who have never used premenopausal progestogens. One interesting finding was that not only women with endometriosis are at higher risk for skin cancer, but also women with a family history of skin cancers are at increased risk for endometriosis.

Although these findings point to a strong link between endometriosis and skin cancer, it is still unclear why these two diseases are associated with each other. One working theory is shared environmental (such as sun exposure), genetic (red hair, freckling, eye color, skin sensitivity to sun exposure), and hormonal (no common hormonal pathway has been discovered yet) factors might be responsible for the association between these two diseases. Alternatively, systemic changes caused by endometriosis such as inflammation or altered immune response may be the reason behind increased skin cancer risk. Further research will shed more light on the common pathways shared between these two diseases and explain the association between endometriosis and skin cancer risk.

Research Source: https://www.ncbi.nlm.nih.gov/pubmed/28799019