December 06, 2024
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A new study found that screening and the removal of precancerous polyps accounted for 79% of the 940,000 colorectal cancer deaths averted between 1975 and 2020.
Nearly 1 million colorectal cancer deaths have been averted in the last 45 years primarily due to screenings and the removal of precancerous polyps, a new study shows.
The study, published Thursday in JAMA Oncology, found 79% of the 940,000 lives saved could be attributed to prevention strategies, dwarfing the 21% attributed to colorectal cancer treatment advances.
The researchers found similar disparities between prevention and treatment when looking at four other common cancer types, underscoring the importance of screenings and other prevention strategies in saving lives. Of the 5.94 million deaths averted from breast, lung, cervical, colorectal and prostate cancers between 1975 and 2020, 4.75 million could be attributed to prevention and screening interventions.
Without such measures, the study estimated 3.45 million people would have died from colorectal cancer, which has becoming more common among young adults. Though overall colorectal cancer rates have been declining, they have been increasing 1% to 2% annually among adults since the mid-1990s, according to the most recent report from the American Cancer Society. Colorectal cancer is now the leading cause of cancer death among men under 50 and second among women in the same age range.
For the new study, researchers from the National Cancer Institute used statistical models and cancer mortality data to estimate how prevention, screening and treatment affected outcomes for breast, lung, cervical, colorectal and prostate cancers.
"Although many people may believe that treatment advances are the major driver of reductions in mortality from these five cancers combined, the surprise here is how much prevention and screening contribute to reductions in mortality," said one of the study's lead authors, Katrina A. B. Goddard, director of NCI’s Division of Cancer Control and Population Sciences.
In addition to the colorectal findings, the study also showed that:
• One million breast cancer deaths were averted, with treatment advances attributed to three-quarters of the deaths averted and mammography screening attributed to the rest. Without these interventions, 2.71 million people would have died of breast cancer.
• Smoking cessation programs and other lung cancer prevention efforts accounted for 98% of the 3.45 million lung cancer deaths averted. Without them, 9.2 million people would have died of lung cancer.
• The 160,000 averted cervical cancer deaths were entirely due to screenings (Pap and HPV testing) and the removal of precancerous lesions. Without them, 370,000 people would have died of cervical cancer.
• Of the 360,000 averted prostate cancer deaths, PSA screening was attributed to 56% of them. Treatment advances accounted for the rest. Without these measures, prostate cancer deaths would have totaled 1.01 million.
Colorectal cancer usually starts with abnormal growths, called polyps, inside the colon or the rectum. Polyps are common, and most are benign. But polyps can become cancerous, invade the walls of the colon or rectum and eventually the lymph nodes, if not caught and treated early.
The U.S. Preventive Services Task Force recommends adults ages 45-75 get screened for colorectal cancer at regular intervals. People over 75 should talk to a doctor to make screening decisions based on their medical profiles.
There are several methods of screening for colon cancer. A stool test every 1-3 years checks for tiny amounts of blood that cannot be seen in feces, because polyps and colorectal cancers can bleed. A Colonoscopy – a procedure during which a flexible, lighted tube is inserted through the anus into the rectum with a tool that can remove polyps – is recommended once every 10 years for most people. The Food and Drug Administration also recently approved a blood-based test called Shield for people 45 and older at average risk for colorectal cancer.
