"Hasta ahora teníamos un modelo claro de prueba genética. Se consultaba a un asesor genético, se hacía un conjunto de pruebas y este profesional ayudaba a interpretar los resultados", dijo en un comunicado de prensa de la American Association for Cancer Research Saskia Sanderson, que realizó el estudio cuando aún estaba en la rama de investigación conductual y social del Instituto Nacional de Investigación del Genoma Humano de EE. UU.

"Ese modelo está bajo una presión creciente a medida que se genera más información genética y aumenta la disponibilidad de un mayor número de pruebas genéticas por Internet", agregó Sanderson.

"Lo que encontramos fue alentador ya que las personas que obtenían estos resultados genéticos por Internet los recordaban correctamente, y ninguno se arrepintió de haber tomado la prueba, aunque es importante resaltar que se trataba de un grupo pequeño de fumadores selectos y que otros podrían responder de forma diferente", apuntó Sanderson, asociada posdoctoral del departamento de genética y ciencias genómicas de la Facultad de medicina Mount Sinai de la ciudad de Nueva York.

La prueba en línea evaluada en este estudio analizó la presencia o ausencia del gen GSTM1.

La ausencia del gen ha sido asociada con un riesgo ligeramente mayor de cáncer de pulmón. La mitad de los fumadores del estudio carecían del gen, y todos se autocalificaron correctamente como "de alto riesgo".

De los que portaban el GSTM1, el 55 por ciento se autocalificó como "de menor riesgo", mientras que el 41 por ciento interpretó los resultados como un "riesgo promedio".

Los patrones de interpretación precisa siguieron siendo los mismos a los seis meses después de que los participantes recibieran los resultados de la prueba genética, lo que sugiere que retuvieron la información, apuntó el estudio.

De acuerdo con los investigadores, los participantes apuntaron que los resultados les parecían creíbles, confiables, fáciles de entender, relevantes e importantes.

Los que descubrieron que tenían un mayor riesgo genético para el cáncer de pulmón mostraron un descenso a corto plazo en la confianza de que dejar de fumar pudiera reducir su riesgo para el cáncer de pulmón.

Sin embargo, todos los participantes eligieron usar al menos uno de varios métodos para dejar de fumar.

El estudio aparece en la edición de julio de la revista Cancer Epidemiology, Biomarkers & Prevention.

"La información genética es compleja, y existe un riesgo de que ofrecer información sin filtro resulte en mayor preocupación y en la mala interpretación de los resultados", advirtió en el comunicado de prensa Jamie Ostroff, director de servicios de ciencias conductuales del Centro Oncológico Memorial Sloan-Kettering de la ciudad de Nueva York y miembro del consejo editorial de la publicación.

"Este estudio piloto encontró que hacerse la prueba no implicaba ningún prejuicio y subrayó la importancia de realizar investigaciones en el futuro sobre cómo educar mejor a los fumadores sobre riesgos genéticos y ambientales", dijo Ostroff

FUENTE: American Association for Cancer Research, news release, June 30, 2009

http://www.nlm.nih.gov/medlineplus/spanish/news/fullstory_86339.html

• People open to using online genetic tests
• Study suggests genetic testing may be beneficial, but many questions remain
• Smokers likely to take steps toward quitting after using genetic test

PHILADELPHIA - As scientists continue to decode the human genome and the information becomes publicly available, private companies that offer online genetic testing are multiplying. Scientists at the National Institutes of Health were concerned that perhaps these tests posed a risk.

They evaluated responses to an online test among smokers who did or did not have a common genetic variant associated with risk for lung cancer.

The results, published in a recent issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, raise a new set of questions, but also allay some of the early concerns.

"Up until now we have had a clear model for genetic testing. You see a professional genetics counselor, undergo a battery of tests and that professional helps you interpret your results," said Saskia Sanderson, Ph.D., a postdoctoral fellow in the Department of Genetics and Genomic Sciences at Mount Sinai School of Medicine, who completed the study while working at the Social and Behavioral Research Branch of the National Human Genome Research Institute of the NIH.

"That model is coming under increasing pressure as more and more genetic information is generated, and as a greater number of genetic tests become available on the internet," said Sanderson.

"What we found was encouraging in that people who got these online genetic results recalled them correctly, and no one regretted having taken the test; though it is important to remember that this was a small group of select smokers and that others may respond differently."

Patients at higher risk genetically displayed short-term signs of decreased confidence that quitting smoking could reduce their risk of lung cancer, but scientists did note that all of those who took the test chose to receive at least one of several offered known smoking cessation aids.

"Genetic information is complex, and there is a risk that providing unfiltered information will result in heightened worry and misinterpretation of results," said Jamie Ostroff, Ph.D., chief of behavioral science services at Memorial Sloan-Kettering Cancer Center and an editorial board member of Cancer Epidemiology, Biomarkers & Prevention.

"This pilot study found no harm in undergoing these tests and underscores the importance of conducting future research as to how to best educate smokers about gene-environment risks."

Scientists are reluctant to endorse the tests based on this one study, because the sample was limited to 44 individuals who were biologically related to people with lung cancer and who smoked.

The online test assessed the presence or absence of the GSTM1 gene, the absence of which has been associated with a slightly increased lung cancer risk.

Exactly half of the smokers were missing GSTM1, thus presenting as higher risk and the other half had GSTM1 present. All the GSTM1 missing individuals correctly identified themselves as "higher risk."

Of the GSTM1 present group, 55 percent accurately labeled themselves as "lower risk" while 41 percent interpreted their result as "average risk."

These patterns of accurate interpretation remained at six months, suggesting that these individuals retained the information.

Overall, the individuals taking this test found the results to be believable, trustworthy, easy to understand, relevant and important. At follow-up, no one regretted taking the test.

After taking the test, all of the smokers selected some sort of smoking cessation help with no difference between the higher risk or lower risk groups.

Scientists agreed that regardless of the genetic test result, quitting smoking is the single most important step a smoker can take in preventing lung cancer and that a larger comparison study would be needed to determine if knowledge of genetic risk encourages an individual to quit smoking.

Additional Resources:

Download a photo editorial of Cancer Epidemiology, Biomarkers & Prevention board member Jamie Ostroff, Ph.D.

Subscribe to the Cancer, Epidemiology, Biomarkers & Prevention RSS feed

Learn More about genetic testing and lung cancer through the article "Genetic Link to Lung Cancer" from CR Magazine, the AACR's publication for patients, survivors and scientists. # # #

Media Contact: Jeremy Moore, 267-646-0557
jeremy.moore@aacr.org