Colorectal cancer screening: Estimated future colonoscopy need and current volume and capacity.



In 2014, a national campaign was launched to increase colorectal cancer (CRC) screening rates in the United States to 80% by 2018; it is unknown whether there is sufficient colonoscopy capacity to reach this goal. This study estimated the number of colonoscopies needed to screen 80% of the eligible population with fecal immunochemical testing (FIT) or colonoscopy and determined whether there was sufficient colonoscopy capacity to meet the need.


The Microsimulation Screening Analysis-Colon model was used to simulate CRC screening test use in the United States (2014-2040); the implementation of a national screening program in 2014 with FIT or colonoscopy with 80% participation was assumed. The 2012 Survey of Endoscopic Capacity (SECAP) estimated the number of colonoscopies that were performed and the number that could be performed.


If a national screening program started in 2014, by 2024, approximately 47 million FIT procedures and 5.1 million colonoscopies would be needed annually to screen the eligible population with a program using FIT as the primary screening test; approximately 11 to 13 million colonoscopies would be needed annually to screen the eligible population with a colonoscopy-only screening program. According to the SECAP survey, an estimated 15 million colonoscopies were performed in 2012, and an additional 10.5 million colonoscopies could be performed.


The estimated colonoscopy capacity is sufficient to screen 80% of the eligible US population with FIT, colonoscopy, or a mix of tests. Future analyses should take into account the geographic distribution of colonoscopy capacity. Cancer 2016. © 2016 American Cancer Society.

PCPs Need to Push Colorectal Cancer Screening

Prevention begins with primary care support, says the AAFP.

Every year, more than 140,000 U.S. adults have newly diagnosed colorectal cancer, the nation’s second-leading cause of cancer deaths. Those statistics are startling enough, but what makes them even more troubling is that all over the country, patients miss out on potentially life-saving screenings.

Primary care providers know that screening can detect colorectal cancer in its earliest stages and that it can prevent cancer through the detection and removal of precancerous polyps. Sadly, about one in three adults between 50 and 75 years old are not getting screened as recommended.

The American Academy of Family Physicians has long recognized the importance of colorectal cancer screening. We recommend screening for colorectal cancer using fecal occult blood testing, sigmoidoscopy, or colonoscopy, in adults, beginning at age 50 years and continuing until age 75 years.

We view colorectal cancer as a major public health problem, and we’re not alone. Last year, the AAFP joined dozens of organizations in support of the National Colorectal Cancer Roundtable’s (NCCRT) 80% by 2018 initiative, which seeks to increase the percentage of adults ages 50 and older who get screened for colorectal cancer to 80% by 2018.

Earlier this month, I participated in an event hosted by the American Cancer Society and the NCCRT that looked at the progress we’ve made with the 80% by 2018 initiative. It was a good reminder of how far we’ve come and a great way to celebrate Colorectal Cancer Awareness Month in March. Although screening rates have risen, there is still work to be done.

I’m optimistic about the role that primary care, and specifically family physicians, can play to reach the 80% goal. Approximately one in four office visits are made to family physicians. That’s 214 million office visits a year. Because of our ability to treat a patient over the entire lifespan, we’re able to forge a continuous, trusting bond with our patients. We build relationships and trust over time. By making a recommendation for screening and providing reminders, we can help achieve this important, life-saving goal.

These conversations require a level of sensitivity. Although some patients are hesitant to have a colonoscopy, they may agree to do a take-home test. Remember that a typical series of take-home stool tests does qualify as screening and should be done annually. However, a one-time, in-office stool test does not adequately screen for colorectal cancer.

We also have to be sensitive to health disparities. According to the NCCRT, Hispanics, Native Americans or Alaska Natives, rural populations, men, those 50 to 64, and those with lower education and income are less likely to get tested. In my practice, I discuss the importance of colorectal cancer screening with all of my patients ages 49 to 75. I find that many patients aren’t aware of the different screening options. During these conversations, I do a lot of listening. I want my patients to understand my recommendation and, conversely, I want to understand their concerns. These initial conversations aren’t always successful, but they’re too important to discontinue.

So I follow up with patients. I send reminders, and I encourage other healthcare providers to do the same.

Increasing the screening rate requires extra effort by a lot of different groups. But it’s life-saving work, and it’s worth doing.

Colorectal Cancer Screening: Which Test is Right for Me?

Colorectal cancer is one of the most common cancers in both men and women. It is also considered one of the more preventable cancers due to the effectiveness of screening. But which screening option is right for you?


Charles Fuchs, MD, MPH, and Jeffrey Meyerhardt, MD, MPH, of Dana-Farber’s Center for Gastrointestinal Oncology.
“There are several different appropriate methods for colorectal cancer screening,” explains Jeffrey Meyerhardt, MD, MPH, clinical director of the Center for Gastrointestinal Oncology at Dana-Farber/Brigham and Women’s Cancer Center. “Some of the tests are more sensitive, but more complicated.”

Fecal occult blood testing. One type of screening is fecal occult blood testing, where patients complete a set of stool samples at home and return them to the doctor to test for evidence of microscopic blood. This test has been proven to decrease the incidence of colon and rectal cancers and mortality, and should be done annually.
While fecal occult blood testing is the most convenient method, Meyerhardt recommends the colonoscopy for most patients because of its sensitivity.

Colonoscopy. “The colonoscopy is best able to detect polyps, which are precursors to colorectal cancers, as well as cancer itself,” says Meyerhardt. “Fecal occult blood testing is only considered sensitive for cancer, not polyps, the precursor for most cancers, making it much less comprehensive than a colonoscopy.”
Read more: Colorectal Cancer: Five Things You Need to Know
Colonoscopies are slightly more complicated, and require a liquid diet the day prior to screening, some preparation to clean out the colon and rectum, and an outpatient procedure. If you have a clean colonoscopy, without any concerning polyps or cancer, you need only be screened every 8-10 years. If your physician finds polyps during your colonoscopy, the time between screenings will depend on the size, location, and characteristics of any polyps.

Sigmoidoscopy and barium enema. Other screening options include a sigmoidoscopy, which examines the rectum and lower colon for polyps and needs to be completed every five years, and a barium enema, which is a series of x-rays of the lower gastrointestinal tract. While sigmoidoscopies or fecal occult blood tests are acceptable colonoscopy substitutes for those with no risk factors or symptoms of colon or rectal cancer, barium enemas may miss small polyps and only detect between 30 and 50 percent of the cancers that a standard colonoscopy can find.
“All of the screening tests carry some risks, and the more sensitive the test, the higher the risk,” says Meyerhardt. “During a colonoscopy, there’s a very small risk of a perforation of the bowel, bleeding, or infection. The biggest risk of fecal occult blood testing and other screening measures is missing something, which could turn out to be much more serious.”
All adults aged 50 and older should be regularly tested for colon and rectal cancers. If you have certain risk factors, such as a family history of colon or rectal cancer, Crohn’s disease, ulcerative colitis, or a history of polyps, testing should be considered earlier than age 50. For example, those who have a history of colon or rectal cancer in an immediate family member should begin testing 10 years prior to the age of their family member’s diagnosis. For example, if a sibling or parent was diagnosed at 50, your first screening should take place at the age of 40. For all individuals, the time between testing depends on screening type and risk factors. Discuss the right time for you to start screening for colorectal cancer with your doctor.

Fecal Immunochemical Testing for Colorectal Cancer Screening.

FIT detected most cancers, but only a minority of advanced adenomas.

Fecal immunochemical testing (FIT) might be more accurate than guaiac-based fecal occult blood testing (gFOBT) in screening for colorectal cancer. In this Dutch study, 1256 average-risk patients submitted single specimens for FIT (OC-Sensor) just before undergoing screening colonoscopy.

Colonoscopy identified 8 patients (0.6%) with colorectal cancer and 113 (9%) with advanced adenomas. At a cutoff of 50 ng/mL, FIT was positive in 10% of patients. Sensitivity and specificity of FIT for detecting advanced adenomas were 38% and 93%, respectively. For colorectal carcinoma, sensitivity was 88% (i.e., FIT was positive in 7 of 8 patients with cancer), and specificity was 91%. Five of the seven FIT-positive cancers were localized (Dukes stage A). FIT detected proximal and distal advanced neoplasia with equal sensitivity.

The Journal Watch General Medicine Perspective

According to these findings, if patients were screened initially with a single FIT, most localized cancers and about one third of advanced adenomas would be detected, and 90% of patients (those who were FIT-negative) would avoid colonoscopy. Failure to detect most advanced adenomas is not necessarily a fatal flaw, if additional research shows that repeated FIT screening (i.e., at 1- or 2-year intervals) detects many of these lesions before they progress to unresectable cancers. One of our Journal Watch Gastroenterology editors, an expert in colorectal cancer screening, comments below on FIT.

The Journal Watch Gastroenterology Perspective

Current colorectal cancer screening guidelines recommend that clinicians who use fecal blood testing switch from gFOBT to FIT (Am J Gastroenterol 2009; 104:739). Consistent results from several types of studies, including randomized, controlled trials, indicate that patient adherence (i.e., completion of the test) and test sensitivity strongly favor FIT over gFOBT. Several national screening programs outside the U.S. now are based on FIT, and cost-effectiveness analyses suggest that annual FIT is at least as cost-effective as is colonoscopy every 10 years. Several randomized, controlled trials, including one in U.S. Veterans Administration hospitals) have been organized to compare FIT and colonoscopy.

A practical problem that clinicians encounter when they try to switch to FIT is the lack of comparative performance data on the several commercial FIT assays available in the U.S. Several years ago, in a study of six commercial FITs available in Germany, researchers found that several had awful performance characteristics, including very poor specificity. However, the laboratory-based assay used in the current study (OC-Sensor) has been evaluated in many studies and is believed to perform best.

This Dutch study suggests that FIT is equally effective in both the proximal and distal colon, whereas some previous evidence had suggested better performance in the distal colon. This result is encouraging, but the endpoint for the study was advanced conventional (i.e., tubular, tubulovillous, or villous) adenomas. The study ignores (as do all FIT studies) the 30% of colorectal cancers that arise through a genetic pathway characterized by hypermethylation; the precursors of these cancers are not conventional adenomas but rather serrated lesions (sessile serrated polyps, also known as sessile serrated adenomas). Further, these serrated lesions are located primarily in the proximal colon. Endoscopically, these premalignant serrated lesions have no vessels on their surface, and some evidence shows that they don’t bleed at all. The future of sensitive fecal testing that can identify both conventional and serrated precancerous lesions in the proximal colon is more likely to lie in fecal DNA testing than in FIT.

Source: Journal Watch General Medicine


One-Time Sigmoidoscopy Reduces Colorectal Cancer Incidence, Mortality

A single flexible sigmoidoscopy can reduce colorectal cancer incidence and mortality, according to a study in the Journal of the National Cancer Institute.

Nearly 35,000 adults (aged 55 to 64) in Italy were randomized to sigmoidoscopy or to no screening. Just over half of intervention patients actually underwent sigmoidoscopy.

During 11 years’ follow-up, colorectal cancer was diagnosed in 251 intervention patients and 306 controls, and colorectal cancer–related death occurred in 65 and 83, respectively. In intention-to-treat analyses, sigmoidoscopy was associated with a significant, 18% reduction in cancer incidence and a nonsignificant, 22% reduction in mortality. In per-protocol analyses, the reductions in incidence and mortality were both significant (31% and 38%, respectively).

Despite these findings, an editorialist concludes that the overall evidence doesn’t suggest a large difference in effectiveness of FOBT, flexible sigmoidoscopy, and colonoscopy, so “the U.S. approach of recommending all three screening strategies seems sound.”

source: JNCI