ST. LOUIS — Family history is a strong risk factor for melanoma in women, while age appears to be the biggest risk for the development of basal cell carcinoma, Abrar Qureshi, M.D., said at the annual meeting of the Society for Investigative Dermatology.
Dr. Qureshi of Harvard University, Boston, used data from the ongoing Nurses' Health Study to examine independent risk factors for melanoma, squamous cell carcinoma, and basal cell carcinoma. His study examined incident cases of skin cancer among 113,333 women who were followed from 1984 to 2000.
Basal cell carcinoma was the most common cancer in the group, with 7,854 cases. There were 870 cases of squamous cell carcinoma and 370 cases of melanoma.
Based on a preliminary analysis of the data, Dr. Qureshi concluded that age was the biggest risk factor for basal cell carcinoma. Looking at age-specific incidence rates, between ages 55 and 59 years, the incidence rate was about 700 cases per 100,000 person-years, but after age 65, the rate rose to above 2,000. “You can see, it's quite different above age 65,” Dr. Qureshi said at the meeting.
The incidence rate for melanoma was 44 cases per 100,000 person-years, and the rate of squamous cell carcinoma was 104 cases per 100,000 person-years. Age did not significantly alter the rate of melanoma; there was a slight elevation in the rate of squamous cell carcinoma after 55 years of age.
The strongest risk factor for melanoma was high mole count on one upper extremity (3.5 times increased risk). A family history of a first-degree relative with melanoma and little or no ability to tan increased the risk of melanoma in women by a factor of 2.5. A susceptibility to burn was associated with a 70% increase in the risk of melanoma.
For squamous cell carcinoma, the strongest risk factor was little or no ability to tan and susceptibility to burn (twice the risk). Family history of melanoma was associated with a 1.5 times increased risk of squamous cell carcinoma.
Although the strongest risk factor for basal cell carcinoma in women was age, they had a doubling of risk associated with susceptibility to burn, a 70% higher risk for little or no ability to tan, and a 50% higher risk for a high mole count. Women who had a first-degree relative with melanoma were found to have a 50% higher risk of basal cell carcinoma.
Further multivariate analyses are ongoing, Dr. Qureshi said.
After age 65, the incidence rate of BCC in women was more than 2,000 cases per 100,000 person-years. ©Elsevier 2004. Abeloff: Clinical Oncology 3E