Key Point

The first-degree relatives of African-American individuals with early-onset lung cancer have a greater risk of lung cancer than their white counterparts.

DETROIT—Smokers with a first-degree relative diagnosed with early-onset lung cancer have a higher risk of developing lung cancer with increasing age, compared with smokers without a family history. Furthermore, this risk is especially pronounced in first-degree relatives of African-American individuals with early-onset lung cancer, reported Michele L. Coté, PhD, and colleagues.¹ “These data provide estimates of lung cancer risk that can be used to offer counseling to family members of patients with early-onset lung cancer,” they said.

Dr. Coté, of the Karmanos Cancer Institute at Wayne State University in Detroit, told Pulmonary Reviews that her work “represents 15 years of research—research that originally examined why nonsmokers get lung cancer.” She and her colleagues deduced that if a nonsmoker develops lung cancer, then genetics must be an important contributor to the development of the disease. “This led to examining another interesting group—early-onset lung cancer cases,” Dr. Coté continued. “These people don’t usually have as much of a smoking history compared to their older counterparts.”

Dr. Coté also noted that African-American men have a greater incidence of lung cancer compared with white men, as well as worse survival after diagnosis. “In Detroit, we have a diverse enough population to study African-Americans—many other places do not,” she said. “It is important to examine these racial disparities if you have the resources to do so.”

She and her colleagues did just that. They conducted a study involving 692 individuals with early-onset lung cancer, 773 controls, and 7,576 of their parents and/or siblings. One third of the population was African-American. Among those with early-onset lung cancer, 311 had adenocarcinoma, 90 had small cell lung cancers, 86 had squamous cell carcinoma, 65 had large cell carcinoma, and the remaining 27 had non-specified non–small cell cancer.

After adjusting for age, sex, pack-years, pneumonia, and chronic obstructive lung disease, the researchers found that risk of lung cancer was 1.9 times higher in relatives of African-Americans with early-onset lung cancer compared with their white counterparts; cigarette smoking further amplified this risk. According to the researchers, the increased risk occurred after age 60 in these individuals, with 17.1% of relatives of white patients with early-onset lung cancer and 25.1% of relatives of African-American patients with early-onset lung cancer receiving a lung cancer diagnosis by age 70. No increase in risk was observed in family members of nonsmoking cases.

Dr. Coté and her colleagues said their findings “could be the result of a higher degree of underlying susceptibility or aggregation of unmeasured risk factors for lung cancer in black families.”

The researchers said they are continuing gene association analyses in this study population. In addition, they noted that their group is “part of a large consortium that is collecting families that have [three or more] relatives with lung cancer. Preliminary results from this group have revealed an area on chromosome 6 that may contain a gene, or genes, for lung cancer.”

The researchers suggested that “family history assessment should be included when evaluating smokers or those presenting with symptoms consistent with lung disease. Further characterization of high-risk individuals is important to provide clinicians with counseling tools and to enhance the effectiveness of screening programs.” Dr. Coté added that clinicians could use the figures available in this study to counsel patients and relatives of early-onset cases about their risk for lung cancer.

—Karen L. Spittler

Reference
1. Coté ML, Kardia SL, Wenzlaff AS, et al. Risk of lung cancer among white and black relatives of individuals with early-onset lung cancer. JAMA. 2005;293:3036-3042.

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