Page 10 - Zheng Feng
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Chapter 1



                 COLORECTAL CANCER EPIDEMIOLOGY


                 Colorectal cancer (CRC) is a major public health problem. According to the data in GLOBOCAN
                 (2018), CRC is the second most common cancer in women and the third most common cancer
                 in men, and the second leading cause of cancer-related death in the world. Globally, more
                 than 1.8 million new cases were diagnosed and approximately 881,000 people died from CRC
                       [1]
                 in 2018  . Worldwide, the average age-standardized annual incidence per 100,000 of CRC in
                                                       [2]
                                                                                         th
                 both sexes is 19.7 (male: 23.6 and female: 16.3)  . In 2018, the Netherlands was ranked 10
                 with an age-standardized incidence of 37.8 patients per 100,000 inhabitants  .
                                                                             [3]
                 The  development  of  CRC  is  influenced  by  a  number  of  demographic,  behavioral,  and
                 environmental  factors.  According  to  the  World  Cancer  Research  Fund  (WCRF)/American
                 Institute for Cancer Research’s (AICR) 2018 third expert report, inflammatory bowel disease
                 and risk factors such as aging, smoking, overweight or obesity, high red meat or saturated fat
                 intake, low fruit and vegetable consumption and low physical activity have shown to increase
                 CRC incidence. Other dietary habits and lifestyle factors, including physical activity, sufficient
                 intake of whole grain, dietary fiber and dairy products, regular consumption of vitamin D,
                 calcium and multivitamin supplements, are protective factors that potentially decrease the
                 risk of CRC  .
                          [4]
                 The incidence of CRC has been steadily rising. By 2030, it is estimated that the incidence and
                 mortality will increase by 60% to more than 2.2 million and 1.1 million respectively  . These
                                                                                   [5]
                 figures illustrate the current and future economic burden on society through either direct
                 costs related to treatment and indirect costs due to cancer-related productivity loss  .
                                                                                   [6]


                 COLORECTAL CANCER SCREENING


                 The vast majority of CRCs develop from precursor lesions called colorectal adenomas, which
                 are small noncancerous lesions in the inner layer of the colon and rectum. It usually takes
                                                                                      [7]
                 several years to even decades to complete the malignant transformation to carcinoma  .
                 The survival rates of CRC are inversely correlated with the cancer stage at diagnosis, with
                 5-year survival rates of 90% for early-stage CRC (stage 0 and I according to the tumor-lymph
                 node-metastasis (TNM) classification) to 10% in patients with advanced-stage cancer (stage
                 IV)  [8, 9] . Implementing CRC screening contributes to a decrease in incidence and mortality
                 rates   [10] ,  emphasizing  that  regular  screening  and  early  removal  of  CRC  and  its  precursor
                 lesions are effective strategies to manage the disease and increase survival  [11, 12] .





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