![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif) |
¿Preguntas sobre el cáncer?
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif)
|
1-800-422-6237
(1-800-4-CANCER)
|
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif)
|
Llame de lunes a viernes de 9:00 a.m. a 4:30 p.m., hora local en Estados Unidos y sus territorios. |
|
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif) |
|
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif)
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif)
| Tipo de estudio en el que los pacientes (ciego simple) o los pacientes y sus médicos (doble ciego) no conocen qué medicamento o tratamiento van a recibir. Lo opuesto a un estudio ciego es un estudio abierto o no enmascarado. |
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif)
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/gray_spacer.gif)
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif)
|
![](https://webarchive.library.unt.edu/eot2008/20081102043958im_/http://www.nci.nih.gov/images/spacer.gif) |