Emily Whittington, a radiation therapist at Vanderbilt-Ingram Cancer Center, pulls down a mask intended to guide radiation beams into patients with head and neck cancer. Emily Siner/NPR hide caption

itoggle caption Emily Siner/NPR

Proton beam therapy can precisely target tumors to avoid harming surrounding tissue, advocates say. Blythe Bernhard/St. Louis Post-Dispatch/MCT/Landov hide caption

itoggle caption Blythe Bernhard/St. Louis Post-Dispatch/MCT/Landov

Defensive tackle Devon Still says that being on the Cincinnati Bengals' practice squad will let him keep his insurance — and to stay close to his daughter, who's battling cancer. Christian Petersen/Getty Images hide caption

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First-year medical student Michelle Gentile assists her classmate Abbie Harts as she performs a pelvic exam on a volunteer at Northwestern University. Joshua Lott/Reuters /Landov hide caption

itoggle caption Joshua Lott/Reuters /Landov

Two cervical cancer cells divide in this image from a scanning electron microscope. Steve Gschmeissner/Getty Images/Science Photo Libra hide caption

itoggle caption Steve Gschmeissner/Getty Images/Science Photo Libra

Elizabeth, Samuel, Bryan and Noah Shaw amid Texas bluebonnets on Easter Sunday. Samuel was conceived with in vitro fertilization so he would not suffer from the hereditary cancer that afflicted Noah. Courtesy of Elizabeth Shaw hide caption

itoggle caption Courtesy of Elizabeth Shaw

TV host Samantha Harris says she will have a double mastectomy after being diagnosed with breast cancer. But the surgery doesn't eliminate cancer risk. Jordan Strauss/Invision/AP hide caption

itoggle caption Jordan Strauss/Invision/AP