Despite the availability of screening tests, almost half of cervical and colorectal cancer cases in the U.S. are diagnosed at late stages, when the disease is more difficult to treat.
That’s the conclusion of a CDC report out today, which also found that a third of breast-cancer cases are caught at a late stage. “More work is needed to widely implement evidence-based cancer screening tests which may lead to early detection and, ultimately, an increase in the number of lives saved,” said Marcus Plescia, director of the CDC’s division of cancer prevention and control, in a statement.
The United States Preventive Services Task Force has recommendations for screening for breast cancer, colorectal cancer and cervical cancer (among other diseases.) So does the American Cancer Society. In the case of cervical and colon cancer, screening tests can actually help prevent disease, since they identify pre-cancerous lesions or abnormal cells that can be removed before they progress into a health threat.
Of course, screening tests aren’t perfect. Mammograms, for example, don’t catch all tumors — some aren’t visible on X-rays, and others grow quickly enough to become dangerous even when a woman has regular mammograms. And tests carry their own risks — of complications during a procedure, referral for further procedures that may cause harm and of finding and treating disease that wouldn’t have amounted to a health threat were it left alone.
But many people fail to get tests backed by scientific evidence and recommended by the USPSTF and ACS. The report says 62% of adults met recommended screening guidelines for colorectal cancer, while 81% of women aged 50-74 reported having a mammogram in the previous two years and 88% of women for whom cervical cancer screening was recommended said they’d received a Pap test in the previous three years.
The incidence of late-stage disease varied by age, ethnicity and geography, the CDC says. For example, black men and women tended to have both higher rates of late-stage cancer — as measured by number of cases per 100,000 people — and also higher percentages of late-stage cancer, meaning a larger proportion of total cancers caught at a late stage. Incidence of late-stage colorectal cancer also increased with age, and late-stage breast cancer incidence was highest among women aged 70-79. Late-stage cervical cancer incidence rates were highest among women aged 50-79 and Hispanics.
Read the full report for a list of the study’s limitations, including the self-reporting of screening tests and lack of high-quality incidence data for two states.
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