Frequent Basal Cell Carcinomas Linked to Increased Risk of Other Cancers

Patients with frequent basal cell carcinomas, a common skin cancer, may be more likely to develop other types of cancer, according to a study published by JCI Insight.

The findings of the study suggest that the increased risk may be attributed to a gene mutation in the proteins that repair damaged DNA. Patients with this mutation may be more susceptible to cancers of the blood, breast, colon, and prostate, the authors noted.

“We discovered that people who develop 6 or more basal cell carcinomas during a 10-year period are about 3 times more likely than the general population to develop other, unrelated cancers,” study lead author Kavita Sarin, MD, PhD said in a statement. “We’re hopeful that this finding could be a way to identify people at an increased risk for a life-threatening malignancy before those cancers develop.”

The skin is the body’s largest organ and it’s also the most vulnerable to ultraviolet (UV) rays from sun exposure. Because UV rays can damage DNA, the proteins that repair DNA are vital in the prevention of skin cancers, according to the study.

Basal cell carcinomas develop when the DNA repair system falls behind, leaving the DNA damaged. They are common, with over 3 million cases in the United States each year, but usually highly treatable, according to the authors.

“About 1 in 3 Caucasians will develop basal cell carcinoma at some point in their lifetime,” Dr Sarin said.

The authors set out to determine if the skin could predict whether a patient is more susceptible to other cancers. They looked for mutations in 29 genes that play a role in repairing DNA in a cohort of 61 patients who were frequently diagnosed with basal cell carcinoma, with patients averaging 11 diagnoses over a 10-year period.

The researchers found a significant amount of gene mutations in patients with frequent basal cell carcinomas.

“We found that about 20 percent of the people with frequent basal cell carcinomas have a mutation in one of the genes responsible for repairing DNA damage, versus about 3 percent of the general population. That’s shockingly high,” Dr Sarin said in the press release.

According to the findings, patients with frequent basal cell carcinomas are 3 times more likely to develop additional cancers than the average person. Out of the 61 patients examined, 21 had experienced additional cancers, including blood cancer, melanoma, prostate cancer, breast cancer, and colon cancer.

The researchers confirmed their findings by analyzing insurance claims from more than 13,000 patients who had over 6 basal cell carcinomas and discovered similar results—these patients were also 3 times more likely to develop other forms of cancer.

The study determined that a patient’s risk of developing other cancers increased with the amount of basal cell carcinomas they’ve had, according to the authors.

“I was surprised to see such a strong correlation, but it’s also very gratifying,” Dr Sarin said. “Now we can ask patients with repeated basal cell carcinomas whether they have family members with other types of cancers, and perhaps suggest that they consider genetic testing and increased screening.”

Moving forward, the research team plans on examining more patients with frequent basal cell carcinomas, and eventually conduct a similar study on patients with melanoma.

Reference

Common Skin Cancer Can Signal Increased Risk of Other Cancers [news release]. Stanford Medicine News Center. August 9, 2018. http://med.stanford.edu/news/all-news/2018/08/common-skin-cancer-can-signal-increased-risk-of-other-cancers.html Accessed August 9, 2018.