Growing concern among young Americans
Rates of colorectal cancer are rising for the under-50 crowd, but declining for those over 50 to 55. Those findings, reported by the American Cancer Society in its May 2018 Colorectal Cancer Screening Guideline, caused ACS to recommend that average-risk adults aged 45 years and older undergo regular screening with either a high-sensitivity stool-based test (e.g., iFOBT) or a structural – visual – exam, based on personal preferences and test availability. As a part of the screening process, all positive results on non-colonoscopy screening tests should be followed up with timely colonoscopy, according to ACS.
True, the Society calls its most recent guideline a “qualified recommendation,” whereas its prior recommendation for regular screening in adults aged 50 years and older remains a “strong recommendation.” Nevertheless, ACS issued its recommendation based on a systematic evidence review of colorectal cancer screening literature and modeling analyses.
Not every professional group is completely onboard with the ACS recommendation. The U.S. Multi-Society Task Force (MSTF) on Colorectal Cancer – which represents the American Gastroenterological Association, American College of Gastroenterology, and the American Society for Gastroenterological Endoscopy – is standing by its 2017 recommendations, which call for screening for colorectal cancer beginning at age 50 years in average-risk people, except in African-Americans, in whom some evidence supports screening at 45 years. Nevertheless, MSTF recognizes that earlier screening may improve early detection and prevention of colorectal cancer. At the very least, the Task Force acknowledges that the ACS recommendation will stimulate discussion and further research on the risks and benefits of earlier screening.
Onset among the young
Colorectal cancer (CRC) is the fourth most commonly diagnosed cancer among adults in the United States, reports the ACS. Over 140,000 Americans were expected to be diagnosed with it in 2018. It is the second leading cause of cancer death, leading to over 50,000 deaths annually. The highest incidence and mortality rates are among African-Americans, American Indians, and Alaska Natives.
Risk factors associated with a Western lifestyle that have been shown to increase CRC risk include: cigarette smoking; excess body weight; diet, including high consumption of alcohol and red and processed meat and low consumption of fruits/vegetables, dietary fiber, and dietary calcium; and physical inactivity, says ACS. The risk for developing colorectal cancer is associated with several identified hereditary conditions, including family history; medical conditions, including chronic inflammatory bowel disease and type 2 diabetes; and a history of abdominal or pelvic radiation for a previous cancer.
Among adults younger than 55 years, the incidence of colorectal cancer increased 51 percent from 1994 to 2014, and mortality increased 11 percent from 2005 to 2015.
“Young onset rates of colorectal cancer are absolutely rising, and we as clinicians need to be cognizant of that when we see our young patients in the office who present with digestive complaints of concern,” says Sophie M. Balzora, MD, FACG, who is chair of the American College of Gastroenterology’s Public Relations Committee and of the NYU School of Medicine. It is not clear why colorectal cancer is increasing in this population, she adds.
While Balzora could not comment on ACG’s behalf on the American Cancer Society’s newest recommendations, “what I can say is that the recognized increased rate of rectal cancer in those under age 50 has sounded an alarm, and heightens the importance of informing patients in this age group to not ignore their digestive symptoms and to seek the care of their physician sooner, rather than dismissing symptoms. This is something we have always stressed, but this message is more important now than ever.”
The good news
If there is good news to report, it is this: Colorectal cancer incidence and mortality among adults aged 55 years and older have shown a decline for several decades, which accelerated around 2000, particularly among adults aged 65 years and older, according to ACS. Although changes in exposure to risk factors account for an estimated one-half of the reduction in incidence and one-third of the reduction in mortality before 2000, subsequent accelerated declines in incidence and mortality since 2000 are largely attributable to increased screening, with improved treatment also contributing to mortality reduction.
“Screening saves lives, and this group [those aged 55 and over] has been heavily targeted, which is fantastic to see,” says Balzora.
“The ‘Katie Couric Effect’ was a true phenomenon that increased colorectal cancer screening rates tremendously,” she says, referring to the efforts of the journalist and author. “Having her colonoscopy nationally broadcast on live television in March 2000 was an innovative and extremely successful method of driving home the importance of colorectal cancer screening.
“As gastroenterologists, we strive to prevent colorectal cancer over detecting it, which is why we feel colonoscopy is the best test, as it can truly prevent colorectal cancer, as well as detect it,” says Balzora.
Stool-based, noninvasive testing – such as iFOBT, or FIT – does not prevent colorectal cancer, because its primary goal is to detect colorectal cancer, and not precancerous polyps, she says. “But ultimately, the best test is the one that gets done (properly)!”
FIT testing is an excellent noninvasive alternative to colonoscopy, assuming that patients follow through by getting a colonoscopy should the FIT test return positive, says Balzora. “FIT has a significant advantage over FOBT testing, as it is specific to lower intestinal bleeding, and is a better, more accurate test overall compared with FOBT testing.”
Resources:
American Cancer Society Colorectal Cancer Screening Guideline (2018), https://www.cancer.org/health-care-professionals/american-cancer-society-prevention-early-detection-guidelines/colorectal-cancer-screening-guidelines.html
Colorectal Cancer Screening: Recommendations for Physicians and Patients From the U.S. Multi-Society Task Force on Colorectal Cancer, July 2017, Gastroenterology (https://www.gastrojournal.org/article/S0016-5085(17)35599-3/fulltext)
American Cancer Society Guideline for CRC Screening, 2018
The American Cancer Society recommends that adults aged 45 years and older with an average risk of colorectal cancer (CRC) undergo regular screening with either a high-sensitivity stool-based test or a structural (visual) examination, depending on patient preference and test availability. As a part of the screening process, all positive results on non-colonoscopy screening tests should be followed up with timely colonoscopy.
The recommendation to begin screening at age 45 years is a qualified recommendation.
The recommendation for regular screening in adults aged 50 years and older is a strong recommendation.
The ACS recommends that average-risk adults in good health with a life expectancy of greater than 10 years continue CRC screening through the age of 75 years (qualified recommendation).
The ACS recommends that clinicians individualize CRC screening decisions for individuals aged 76 through 85 years based on patient preferences, life expectancy, health status, and prior screening history (qualified recommendation).
The ACS recommends that clinicians discourage individuals over age 85 years from continuing CRC screening (qualified recommendation).
SUBHEAD: Options for CRC screening
Stool-based tests:
- Fecal immunochemical test every year.
- High-sensitivity, guaiac-based fecal occult blood test every year.
- Multitarget stool DNA test every 3 years.
Structural examinations
- Colonoscopy every 10 years.
- CT colonography every 5 years.
- Flexible sigmoidoscopy every 5 years.
Source: Colorectal cancer screening for average-risk adults: 2018 guideline update from the American Cancer Society, CA: A Cancer Journal for Clinicians, https://onlinelibrary.wiley.com/doi/full/10.3322/caac.21457#caac21457-tbl-0001
U.S. Multisociety Task Force on Colorectal Cancer: Statement regarding new recommendations
The MSTF has previously recommended that colorectal cancer screening for average-risk persons (persons who do not have a family history of colorectal cancer in a first-degree relative) begin at age 45 years in African Americans and age 50 in other groups. The MSTF has reviewed the recent recommendation from the American Cancer Society (ACS) to lower the age to begin screening from 50 to 45 years in all Americans. This change was a qualified recommendation based largely on a modeling study utilizing updated data on the incidence of colorectal cancer in younger people.
Evidence from screening studies to support lowering the screening age is very limited at this time. Based on the modeling study used to support the ACS recommendation, the MSTF recognizes that lowering the screening age to 45 may improve early detection and prevention of CRC. The MSTF expects the new ACS recommendation to stimulate investigation that will clarify the benefits and risks of earlier screening.
As the MSTF has previously noted and discussed, rates of colorectal cancer are increasing in Americans down to age 20 years. Beginning screening at 45 years addresses only part of the increasing risk of colorectal cancer in young persons. For all persons under 50 years, it remains critical to promptly assess symptoms consistent with colorectal cancer. In particular, rectal bleeding and unexplained iron deficiency anemia have substantial predictive value for colorectal cancer and should be thoroughly evaluated.
Source: U.S. Multisociety Task Force on Colorectal Cancer, June 14, 2018, https://www.gastro.org/press-release/statement-from-the-u-s-multisociety-task-force-on-colorectal-cancer