Pregnancy does not increase expectant mothers' melanoma risk

Melanoma is known for its aggressive nature and ability to spread to other organs. But what is less known is that it's the most common cancer arising during pregnancy, accounting for 31 percent of all malignancies among expectant mothers.^1.2

For decades there has been some belief that pregnancy has an adverse effect on the course of melanoma, increasing the risk of its development, ability to spread throughout the body, and recurrence, said study coauthor Mark Faries, MD, FACS, who was director of therapeutic immunology at the John Wayne Cancer Institute, Santa Monica, Calif. at the time the study was conducted.

To determine whether this long held belief is true, investigators from John Wayne Cancer Institute utilized their institution's melanoma database to analyze data on 2,025 women age 18 to 50 diagnosed with stage I to IV melanoma who were treated at their institution between 1971 and 2016.

"In general what is important to note about melanoma is that its incidence continues to increase fairly rapidly, particularly among young women in their 20s and 30s, the same group that would be affected by a pregnancy-associated melanoma," Dr. Faries said. "So it's crucial to make sure that these women are getting appropriate screening and treatment."

For this study, Dr. Faries and colleagues identified 156 women who had developed melanoma during pregnancy. They analyzed patient factors such as age, stage at diagnosis, histologic type, Breslow thickness (a measurement of how deep the tumor is), and ulceration.

Further, they conducted multiple analyses to compare overall survival rates, disease-free survival rates, and melanoma specific survival rates of pregnant women to their non-pregnant counterparts diagnosed with melanoma.

They found that patient factors were similar for pregnancy-associated melanomas and non-pregnancy associated melanomas with no significant differences in Breslow thickness, histologic type, or where the tumor first appeared on the skin. There was also no difference in stage at diagnosis, on average.

In addition, the investigators found that recurrence rates were similar between the two groups. About 38 percent of pregnant women had a melanoma recurrence compared with 36 percent of their non-pregnant counterparts.

Importantly, analyses of overall survival rates and melanoma-specific survival rates for pregnancy-associated melanomas versus non-pregnancy-associated melanomas in stages 0 to III melanoma showed no differences (due to the lack of patients with stage IV melanoma, those patients were excluded from the analyses). At 10 years, disease-free survival was 65.7 percent and 62.3 percent for the non-pregnant women and pregnant women, respectively.

This study upends the long held belief that pregnancy and melanoma are an adverse combination. Instead, it shows that the prognosis for patients who are pregnant is not different from patients who are not pregnant, Dr. Faries explained. "Pregnant patients should be screened for melanoma in a similar manner to non-pregnant patients and should be counseled that their prognosis is not adversely affected by pregnancy. This finding should be very reassuring to both the patients and physicians who are involved in their care."

Melanoma causes the death of about 9,700 lives in the U.S. each year, according to the American Cancer Society.3 That's why everyone should be aware of skin cancer prevention and take steps to detect it early. In fact, pregnancy might be an opportune time for patients who are at risk for melanoma to get examined for irregular spots on their skin, since they are probably seeing physicians more often than they otherwise would, Dr. Faries added.