Screening for early-stage disease remains vital to cancer prevention. New technologies are especially needed for cancers such as ovarian and pancreatic cancer, which often do not produce symptoms until they have spread from the tissue of origin. To this end, NCI launched the Early Detection Research Network to fund a diverse consortium of researchers attempting to turn molecular biomarkers of cancer into useful clinical tools.
NCI performs and funds research to improve existing screening technologies, as well. Dr. Philip Castle of DCEG is validating several molecular tests to screen women for clinically relevant types of human papillomavirus (HPV). For years Pap smears have successfully detected precancerous cervical lesions, but molecular tests for cancer-causing types of HPV are more clinically sensitive and are better precancer predictors than Pap smears and other cytologic methods.
"The goal essentially for these kinds of tests is to make the current screening system more efficient," explained Dr. Castle. "HPV testing is a more clinically sensitive test than cytology, so you can go to longer screening intervals among women who test negative for cancer-causing types of HPV because of the greater reassurance. This in turn reduces the overall cost of the cervical cancer prevention program, which is billions of dollars annually, without reducing the effectiveness."
Dr. Castle and colleagues are working on increasing cervical cancer screening for disadvantaged women worldwide, where more than 80 percent of cervical cancer is found. DCEG's Mississippi Delta Project has partnered with local organizations to test the effectiveness of HPV testing using self-collected cervicovaginal samples in a population of medically underserved women living in the rural southern United States.
Improving access and compliance is important for all types of cancer screening. "You can have the most effective test available, but if you can't get physicians to recommend it, and you don't address patient barriers to using it, it's not likely to benefit the public health," said Dr. Helen Meissner, chief of the Applied Cancer Screening Research Branch in DCCPS.
NCI has extensive research efforts underway "to understand factors that improve compliance with screening from a health care delivery and systems standpoint," explained Dr. Rachel Ballard-Barbash, associate director of DCCPS's Applied Research Program. "This may involve developing automated systems that prompt physicians to encourage their patients to undergo screening or remind patients to schedule appointments for screening, as well as systems for improving how screening tests, such as mammograms, are interpreted by radiologists. The assumption that all the focus of attention needs to be with the individual person rather than the system of health care delivery may miss major opportunities to make great improvements in health care."