Should we screen for colon cancer from age 45? | Lifestyle.INQ

OCTOBER 27, 2022

Through the use of Live Cell Confocal Fluorescence Microscope (LCCF), microbi¬ologists are able to see the behavior of stem cells. This illustration shows an “en-gineered” dendritic cell engulfing a cancer cell. (Photo courtesy of The Medical City’s IPMM laboratory which is the first hospital in Asia to own a LCCF Microscope)

Over the last decade, there has been an increasing incidence of colorectal cancer (CRC) in persons younger than 50 (young-onset CRC) in the United States, especially among high-risk African Americans and Caucasians.

CRC was in the spotlight in 2020 after “Black Panther” star Chadwick Boseman died from the disease at the young age of 43.

CRC is a malignant tumor in the colon or rectum. The Global Cancer Observatory (Globocan) reports that CRC is the third most prevalent cancer in the world, with close to 2 million new cases annually.

CRC also ranks as the third most common cancer in the Philippines, next to breast and lung cancers. In 2020, an estimated 17,364 new patients in the Philippines were reported to be diagnosed with colon and rectal cancer.Screening is the process of looking for cancer or precancerous lesions in people who have no symptoms of the disease.

The high prevalence of CRC all over the world makes screening so much more important, as it is a preventable and screenable cancer.

Screening for CRC is one of the most powerful tools in beating this cancer. Screening can diagnose this cancer early, when there is the best chance for cure.

There are two major methods for screening: A colonoscopy is the gold standard, while the stool test—fecal immunochemical test (FIT)—looks for occult (unseen) blood coming from the colon. The latter test is the one typically used in established CRC population screening programs in the world.

Almost all CRCs start as benign growths called polyps. A polyp may take as long as 10 years to develop into cancer.

The advantage of using a colonoscopy for screening is that gastroenterologists can visualize and remove polyps before these turn into cancer.

In almost all countries in the world, screening average-risk patients starts at age 50. Screening can save lives and has been shown to reduce the risk of CRC by as much as 70 percent, so that means seven out of 10 cases can be saved if detected early.

Worldwide campaign

Colon Cancer Awareness is a massive worldwide campaign for screening, which had its beginnings in the United States in 2000. After a decade, the Philippines joined this crusade, and The Medical City is among the pioneer institutions that promoted this advocacy.

After extensive analysis, the United States Preventive Services Task Force (USPSTF) changed its recommendations to begin screening average-risk persons for CRC from age 50 to 45.

The recommendation was based on systematic review and comparative modeling studies of more recent American patient data and the government’s capacity of their health-care resources to respond to these added needs.

The body concluded with high certainty that screening for CRC in adults aged 50 to 75 years has substantial net benefit (recommendation A). In addition, the task force also concluded with moderate certainty that screening for CRC in adults aged 45 to 49 years has moderate net benefit (recommendation B).

The applicability of these guidelines to Philippine patients remained unanswered.

The Medical City, in collaboration with the Department of Health, organized a successful virtual symposium on CRC screening on March 4. I chaired the session as the lead for the institution’s Colon Cancer Screening Advocacy Program.

The discussion of this USPSTF recommendation on the new screening age of 45 in the Philippine medical setting was among the highlights. The lecture “45 is the New 50 in CRC: How feasible is it in the Philippines?” was given by professor Jose Sollano, former president of the Philippine Society of Gastroenterology and the Philippine Society of Digestive Endoscopy.

Do we automatically adopt these American guidelines, despite the big difference in genetics, environmental factors and national government resources?

We cited that Americans, especially African Americans, are at a much higher risk of CRC than Filipinos, owing to their genetics, Western diet and lifestyle, like with obesity. Based on Globocan, the age standardized incidence rate for CRC in the United States is around 25.6 per 100,000, while that of the Philippines is 18.8 per 100,000. In addition, the Philippines is a low-resource country without even a national screening program for CRC.

Efficient system needed

Sollano analyzed the Philippine data to answer whether age 45 should be accepted as the new recommendation for screening of average-risk Filipinos. However, he stressed that there is no data available yet in the Philippines that can demonstrate an increase in patients with young-onset CRC, unlike in Western medical literature.

The screening guidelines of other Asia-Pacific countries are still recommending the start of screening at the age of 50.

Moreover, some of these developed Asia-Pacific countries have already established their own CRC screening programs. The cost-effectivity of lowering the screening age has not yet been demonstrated in the East.

In building a CRC screening program, the government and other stakeholders need data, infrastructure, personnel and funds. An efficient system of screening millions of Filipinos and the needed recall of those who tested positive with FIT must be in place in order for the program to be successful.

Sollano also underscored that “there are only more than 500 board-certified gastroenterologists for 104 million Filipinos in the whole country.” Expanding the screening to include additional lower-aged patients will likely overwhelm the program and the medical professionals.

“Without any data, infrastructure or funds from the national government, [it] may not yet be feasible in the Philippines,” Sollano concluded. —CONTRIBUTED

The author is a consultant gastroenterologist at The Medical City and is the lead specialist in charge of the annual Colon Cancer Awareness activities of the hospital.

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