June 23, 2021

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Colorectal cancer: You should know two key issues except colonoscopy

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Colorectal cancer: You should also know two key issues except colonoscopy

Colorectal cancer: You should also know two key issues except colonoscopy.  With the improvement of people’s health awareness, the role of cancer prevention in the diagnosis and treatment of various cancers has become more prominent. As far as colorectal cancer is concerned, maintaining healthy living habits and conducting colorectal cancer screening on time and rationally are effective methods for the prevention and early detection of colorectal cancer.

On May 23, 2021, American Digestive Disease Week (DDW) held a lecture on “cancer prevention”. In this lecture, experts and scholars from all over the world combined the latest guidelines and research results to focus on and discuss the interval colorectal cancer that occurs during the screening interval, and the impact of a healthy lifestyle on the prevalence of colorectal cancer.

01. Interval colorectal cancer in the screening of stool immunochemical test cannot be ignored

In recent years, fecal immunochemical test (FIT), colonoscopy and other colorectal cancer screening and examination methods have become more popular, and the problem of intermittent colorectal cancer (IC) has emerged, which has attracted more and more attention from both doctors and patients. In this topic, Dr. Wen-Feng Hsu from National Taiwan University Hospital introduced the results of a cohort study on FIT septal colorectal cancer (FITIC) and colonoscopy colorectal cancer (PCCRC).

According to the definition of the World Endoscopy Organization, FICIC refers to colorectal cancer diagnosed before the next FIT cycle (within 1 year) after a negative FIT screening result, while PCCRC refers to colorectal cancer diagnosed after colonoscopy where no colorectal cancer is found (Within 3 years after discovery of advanced adenoma, within 5 years after discovery of non-advanced adenoma, or within 10 years after negative colonoscopy).

Previous studies have shown that adenoma detection rate (ADR) is an independent predictor of PCCRC. The higher the ADR, the lower the incidence of PCCRC, but this result is mainly derived from the colonoscopy-based screening project. The incidence and long-term results of rectal cancer in the FIT screening cohort have not been clearly reported.

A total of 2,746,478 subjects registered in the Taiwan Colorectal Cancer Screening Program database from 2004 to 2012 were included in the study. Interval colorectal cancer was the main outcome indicator, and patients with colorectal cancer were followed up to 2016. , To compare the incidence and survival rates of FITIC and PCCRC. The study will also divide the participating hospitals into high ADR group (ADR> 42%), medium ADR group (18% ≤ ADR ≤ 42%) and low ADR group (ADR <18%) to analyze the effects of ADR on the occurrence and prognosis of septal colorectal cancer Impact.

The results showed that 1825 cases of FITIC and 288 cases of PCCRC occurred in the included population, mainly in people older than 60 years old. The average annual incidence of PCCRC (0.73/1000 person year) was higher than FITIC (0.14/1000 person year). In the high ADR group that underwent colonoscopy, the incidence of PCCRC was lower and occurred more in the proximal colon, while in the medium or low ADR group, PCCRC occurred more in the distal colon.

It is worth noting that although there are fewer PCCRCs in the high ADR group, the proportion of distant metastases (stage IV) is significantly higher than that of the middle ADR group, low ADR group and FITIC group, and the 5-year survival rate is also the lowest (57.5%). Compared with the FITIC group (70.1%), the low ADR group (80.8%) and the medium ADR group (81.2%), the 5-year survival rate for interval colorectal cancer was roughly the same. After controlling for gender, age, tumor location and treatment methods as confounding factors, the risk ratio of death of PCCRC in the high ADR group was 1.94 (95% CI: 1.01-3.80) compared with the middle ADR group.

Dr. Wen-Feng Hsu believes that in interval colorectal cancer, although the annual average incidence of PCCRC is higher than FITIC, because FITIC is more popular, FITIC still accounts for the vast majority of cases and deaths.

Therefore, it is very important to further improve the sensitivity of FIT to advanced adenoma and early colorectal cancer. Its main methods are to pay attention to the preservation quality and quantity of stool specimens, to further determine the positive cut-off value, and to shorten the interval between screening tests, etc. .

Dr. Wen-Feng Hsu pointed out that most of the missed lesions in the high ADR group may be sessile serrated adenomas and non-granular lateral developmental tumors, which mostly occur in the proximal colon, and the biological behavior and prognosis of such lesions are even greater. Poor, if it is missed, the progress will be faster. For colonoscopy in the medium and low ADR groups, the quality of the examination should be further improved to avoid missing potentially malignant distal polyp lesions.

02. Significant benefits from a healthy lifestyle after colonoscopy

The main points of healthy lifestyle recommended by the World Cancer Research Foundation and the American Association for Cancer Research (WCRF/AICR) include weight control, increased physical exercise, consumption of whole grain foods, reduction of red meat and processed food intake, and restriction of alcohol consumption.

Studies have shown that a healthy lifestyle can help reduce the incidence of colorectal cancer (CRC) and all-cause deaths. On the other hand, the 2020 US Multi Society Task Force guidelines recommend that patients after endoscopic colonic adenoma resection should undergo colonoscopy again within 3 to 10 years according to the number, size, and nature of the adenoma to prevent CRC. occur.

So, for such patients, can maintaining a healthy lifestyle still benefit?

To explore this issue, Professor Mingyang Song from Harvard University and his team analyzed data from three large cohort studies (NHS, NHS2, HPFS). Based on the five aspects of smoking status, BMI, physical exercise, alcohol consumption, and eating habits (processed meat, red meat, whole grains, dietary fiber, dairy products, calcium supplements), the study evaluated lifestyle scores of the included population (0 To 5 points), analyze the relationship between the score and the incidence of colorectal cancer and all-cause mortality. The confounding factors analyzed and controlled were age at diagnosis, gender, race, aspirin use, family history, number of colonoscopy after surgery, and characteristics of adenoma (size, number, location, histology).

The results of the study found that a healthier lifestyle is associated with a lower colorectal cancer [HR per 1-score=0.83 (0.70-0.98), P-trend=0.03] and the risk of death [HR per 1-score=0.81 (0.78- 0.85), P-trend<0.001] is related, and this trend is present in serrated adenomas and traditional adenomas. Assess the relationship between preoperative and postoperative lifestyle health scores and the risk of colorectal cancer and all-cause mortality, and found that a healthy lifestyle after surgery (not preoperative) is more effective in reducing the incidence of colorectal cancer and all-cause mortality Great contribution.

This study is the first large-scale prospective cohort study to evaluate the relationship between lifestyle and the risk of colorectal cancer and all-cause death after adenoma surgery. Professor Mingyang Song emphasized that maintaining a healthy lifestyle is still very important for the prevention of colorectal cancer and premature death after colorectal adenoma surgery, and it is not too late to change the lifestyle after surgery. Healthy lifestyles to prevent colorectal cancer mainly include high-quality diet, non-smoking, non-drinking, control of BMI (18.5-24.9 kg/m2), and adherence to moderate to high-intensity physical exercise.

In summary, the cancer prevention topic of this year’s DDW focuses on issues that are easily overlooked in colorectal cancer prevention programs by various screening methods, such as interval colorectal cancer occurrence, and on the other hand, it emphasizes that individuals maintain good living habits. The important role of CRC provides a key perspective for the clinical prevention, diagnosis and treatment of colorectal cancer from the perspective of both doctors and patients.

(source:internet, reference only)


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