"This study adds a history of the relatively favorable non-melanoma skin cancer -- in and of itself -- to the list of known risk factors for melanoma in both sun lovers and shade dwellers alike," said lead author Carol A. Rosenberg, M.D., assistant professor medicine at Northwestern University Feinberg School of Medicine.
Rosenberg is also director of Preventive Health Initiatives, a senior attending physician at Evanston Northwestern Healthcare and a researcher at The Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
The study found that postmenopausal, non-Hispanic white women aged 50 to 79 years with a history of non-melanoma skin cancer, such as basal cell or squamous cell skin cancer, but no other malignancies were more than twice as more likely to develop cutaneous melanoma over a period of 6.5 years compared with women who had no history of non-melanoma skin cancer, no matter how much sun exposure or other lifestyle variables they have experienced.
"Our study further defines melanoma risk in post-menopausal women and, it is hoped, will sensitize the medical community to this risk, serving as a catalyst for development of new routines of follow-up and patient assessment to facilitate earlier detection of melanoma," said Rosenberg.
"This skin surveillance imperative may serve to be lifesaving in predisposed women," said Rosenberg.
Non-melanoma skin cancer is the most common -- yet largely undocumented -- form of cancer in the United States.
According to the American Cancer Society, more than 1.3 million cases of non-melanoma skin cancers are diagnosed yearly.
But because these types of cancers often carry a favorable prognosis, patients are unlikely to be questioned specifically regarding a history of non-melanoma skin cancer during the course of a routine general physical examination.
Melanoma is all too often a deadly disease because it is very difficult to treat once it has spread beyond its initial site. Although melanoma accounts for only 4 percent of all skin cancers, someone dies every hour from melanoma in the United States.
The ACS estimates that in 2005, almost 60,000 invasive melanomas will be diagnosed in the United States, and nearly 7,770 men and women are expected to die from this disease.
"Regular skin checkups to reduce the incidence of this deadly skin cancer must focus on those at high risk," Rosenberg said. "Diagnosing melanoma early is critical to saving lives."
Results of the study highlight a need for women to talk candidly with their doctors about their history of skin cancer.
Findings from the study further suggest that the causal pathway of the association between non-melanoma skin cancers and melanoma in predisposed individuals may be due to a common gene mutation, Rosenberg said.
Rosenberg's co-authors on this study were Janardan Khandekar, M.D., professor of medicine, and Philip Greenland, M.D., Harry W. Dingman Professor of Cardiology and chair, preventive medicine, Feinberg School of Medicine. Other authors were Rebecca J. Rodabough and Anne McTiernan, M.D., Fred Hutchinson Cancer Research Center, Seattle.
The study is part of the Women's Health Initiative Observational Study (National Heart, Lung, and Blood Institute grant number N01-WH-32108) conducted in 40 communities throughout the United States.