For more than 65 years, the American Cancer Society has been finding answers to critical questions about colorectal cancer (commonly called colon cancer) – what causes it, how can it be prevented, detected, and treated successfully, and how colon cancer patients’ quality of life can be improved.
These efforts have contributed to substantial decreases in colon cancer mortality over the past two decades. Despite this progress, colon cancer is still the third-deadliest cancer in the US, and the Society is committed to saving more lives from this lethal disease. Our research has led to several seminal discoveries that provide hope for the future.
Causes, Prevention, and Detection
- In the 1990s, Society grant recipients Richard Kolodner, PhD, and Bert Vogelstein, MD, led teams that independently identified the first gene known to cause inherited colon cancer. A team that included Vogelstein discovered a genetic change linked with 60% of all colon cancer cases – a finding instrumental in the later development of blood tests for inherited colon cancers.
- Data from the American Cancer Society Cancer Prevention Study II (CPS II) revealed that diets high in red and processed meats increase the risk for colon cancer, but diets high in calcium and low-fat dairy products lower the risk. In addition, greater consumption of folate was linked with lower colon cancer risk.
- A landmark study published in 1991 by American Cancer Society epidemiologist Michael Thun, MD, MS, was the first major study to report a link between aspirin use and a lower risk of fatal colon cancer. More recent research, including findings from Society epidemiologists, indicates that aspirin use could lower the risk of developing not only colon cancer but certain other cancers as well.
- A few years later, Society grantee Michael Garavito, PhD, announced results that paved the way for trials of “super-aspirins” to prevent colon and other cancers. In 2000, the FDA approved the “super-aspirin” celecoxib for the prevention of polyps in individuals with an inherited syndrome linked with colorectal cancer.
- A study from grantee Michael Potter, MD, published in 2009, found that providing home stool testing kits at the time individuals received annual flu shots resulted in an additional 30% of people being screened for colon cancer. Simple strategies like this may be effective for improving screening rates.
Colon cancer is one of only two cancers (the other is cervical cancer) that can actually be prevented through screening. Precancerous polyps – small growths on the lining of the colon or rectum – can be removed before they turn into cancer.
- One of the most common drugs used to treat colon cancer, 5-flurouracil (5-FU), was synthesized by longtime American Cancer Society grantee Charles Heidelberger, PhD, in 1958. For 40 years, 5-FU has been a first-line treatment for colon cancer.
- In the early 1990s, a compound called leukovorin, first used in the treatment of leukemia by American Cancer Society Professor Joseph Bertino, MD, was found to boost the lifesaving value of 5-FU.
- In 1996, the FDA approved Camptosar, a powerful new treatment for advanced-stage colon cancer, developed in part from the work of Society grantee Milan Ptomesil, MD, PhD. More recently, Society grantee Leonard Saltz, MD, found that a combination of 5-FU, leukovorin, and Camptosar extends the life of those with advanced colon cancer.
- Research carried out by several Society-supported investigators, including John Mendelsohn, MD, helped pave the way for FDA approval of the drug cetuximab to treat metastatic colon cancer and also metastatic head and neck cancer.
Tracking Colon Cancer
- Society epidemiologists Rebecca Siegel, MPH, and Ahmedin Jemal, DVM, PhD, biennially publish Colorectal Cancer Facts & Figures, which provides detailed analyses of colon cancer incidence and mortality trends in the US, as well as the latest information on risk factors, early detection, treatment, and current research.
- A study by Society epidemiologist Melissa Center, MPH, found colon cancer incidence rates for both males and females increased in 27 of 51 countries worldwide between 1983 and 2002. The study points to changes in dietary patterns and behaviors that increase the risk of the disease as a likely culprit, and was the first in a peer-reviewed journal to present colon cancer incidence trends across all five continents.
- A study by Society epidemiologist Rebecca Siegel, MPH, found that in sharp contrast to the overall declining rates of colon cancer in the United States, incidence rates among adults younger than age 50 years increased between 1992 and 2005. The authors theorize that these increases may be related to rising rates of obesity and changes in dietary patterns, including increased consumption of fast food.
Understanding and Eliminating Disparities
- A recent study conducted by Society grantee Annette E. Maxwell, DrPH, found that small, community-based, multicomponent interventions significantly increased colon cancer screening among Filipino Americans.
- A study led by American Cancer Society epidemiologist Ahmedin Jemal, DVM, PhD, showed that progress in reducing colon cancer mortality in the US varied significantly across states, with rates in the Northeast showing the most progress and those in the South showing the least progress. The decrease in mortality rates by state correlated strongly with uptake of screening.
Survivorship and Quality of Life
- Kevin Stein, PhD, managing director of the American Cancer Society Behavioral Research Center, is currently collaborating with Scottish researchers to determine if individuals change their diet, physical activity, and tobacco use after a diagnosis of colon cancer, and whether there are any factors that predict such changes. This may contribute to interventions that promote positive lifestyle changes in colon cancer patients, improving their health and overall quality of life.