2700 Original Article Epidemiology characteristics of ethnic minority colorectal cancer in Yunnan in Southwestern China Shaoxiang Wan1#, Qi Tang2#, Daying Feng1, Zaoxiu Hu1, Weiqing Shao1, Yajuan Chen1 1Kunming Medical University, Kunming 650500, China; 2Second People’s Hospital of Yunnan, The Fourth Affiliated Hospital of Kunming Medical University, Kunming 650031, China Contributions: (I) Conception and design: Y Chen, W Shao; (II) Administrative support: W Shao, Y Chen; (III) Provision of study materials or patients: S Wan, Q Tang, Z Hu; (IV) Collection and assembly of data: Q Tang, S Wan; (V) Data analysis and interpretation: S Wan, D Feng; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors. #These authors contributed equally to this work. Correspondence to: Weiqing Shao; Yajuan Chen. Kunming Medical University, 1168 Western Chunrong Road, Yuhua Street, Chenggong New City, Kunming 650500, China. Email: [email protected]; [email protected]. Background: Colorectal cancer (CRC) is one of the world's deadliest cancers, and its mortality rate has been on the rise in China. Yunnan is a region with a higher concentration of ethnic minorities. CRC affects many people from ethnic minority groups, which differ from Han in terms of their age and gender compositions. Methods: We collected samples from 1,016 cases of CRC patients along with their case files at Yunnan Provincial Cancer Hospital from the period between January 2013 and December 2018. Results: In total, 7.1% (n=72) of all lung cancer cases diagnosed from 2013 to 2018 in Yunnan Provincial Cancer Hospital occurred in patients 40 years old or younger, 44% (n=447) were 40 to 60 years old, and 48.9% (n=497) were 60 years old or above. The composition ratio of CRC patients in the different age groups differed significantly and enhanced significantly with age, with a statistical significance of P<0.05. A total of 33.6% (n=38) of 113 minority patients and 16.8% (n=152) of 903 Han patients reported a history of smoking, and 23.0% (n=26) of 113 minority patients and 14.6% (n=132) of Han patients had a history of drinking. Long-term smoking and drinking are significantly associated with the incidence of CRC, and this was more significant among ethnic minorities (P<0.05). Conclusions: The high incidence of CRC in Yunnan is strongly related to patients’ lifestyles, and diet should be a core focus of efforts to prevent and treat CRC. Early screening and regular check for common tumor markers can also help to reduce the incidence of CRC and provide a basis for improvements in CRC treatment and prognosis in Yunnan. Keywords: Colorectal cancer (CRC); ethnic minority; living habits; risk factors Submitted Oct 04, 2019. Accepted for publication Feb 08, 2020. doi: 10.21037/tcr.2020.02.63 View this article at: http://dx.doi.org/10.21037/tcr.2020.02.63 Introduction trend has been seen in recent years. According to the most recent data from the National Central Cancer Registry of Colorectal cancer (CRC) including colon cancer and rectal China (NCCRC), the total number of CRC cases increased cancer is a common malignant tumor. The incidence and from 347,900 (199,700 males and 148,200 females) to mortality of this cancer are both ranked as third among 376,300 (215,700 males and 160,600 females) in the period malignant tumors (1,2). Although the threat of CRC in from 2009 to 2011 (3,4). Moreover, according to the 2016 China is not as severe as in developed countries, an upward Global Burden of Diseases Study, CRC-related cases © Translational Cancer Research. All rights reserved. Transl Cancer Res 2020;9(4):2692-2700 | http://dx.doi.org/10.21037/tcr.2020.02.63 Translational Cancer Research, Vol 9, No 4 April 2020 2693 and deaths in China are currently 392,800 and 167,100, patients from Yunnan Cancer Hospital in the period from respectively, with a predicted increase by 2025 to 642,300 2013 to 2018 were collected and summarized to explore and 221,100, respectively (5). the relationship between special lifestyle and CRC among The pathogenesis of CRC is mainly attributed to the ethnic minority population. The results could provide colorectal adenoma, inflammatory bowel disease, and a scientific basis for identifying the risk factors of CRC and familial hereditary polyposis. In particular, colorectal for the establishment of practical etiological blockade and adenocarcinoma (CRA), a pathological type of CRC, prevention and treatment measures. accounts for 85–90% of CRC precancerous lesions (6). A large number of etiology studies have shown that the Methods development of CRA is a multi-stage, multi-step, multi- gene participation process resulting from a synergy of Materials environmental, dietary, lifestyle, and genetic factors (7). A total of 1,016 patients with CRA, comprising 587 males Nowadays, few effective methods for CRC screening exist. The most common screening methods are relatively and 429 females aged 30 to 79 years old, were involved obvious physical changes such as fecal occult blood and in this study. Clinical data were collected by Yunnan polyps, although these clinical signs cannot completely Cancer Hospital from January 2013 to December 2018. prevent the occurrence of CRC (8). Some genetic screening The diagnosis of colon cancer and rectal cancer in each techniques for CRC, such as the screening for mutations patient was confirmed by pathological biopsy. In addition, in B-Raf proto-oncogene, serine/threonine kinase (BRAF), 1,001 patients with non-tumor colon diseases were also MutL homolog 1 (MLH1), KRAS Proto-Oncogene, recruited from Yunnan Cancer Hospital between January GTPase (K-RAS), the APC regulator of the WNT 2013 and December 2018. These patients comprised 576 signaling pathway (APC) and tumor protein p53 (P53), males and 425 females, aged from 28–80 years old, with Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic an average age of (55.30±12.69) years old. There were no subunit alpha (PIK3CA), and SMAD family member 4 significant differences in age, gender or ethnic composition, (SMAD4), can be used to identify potential high-risk factors educational background or other conventional data between for CRC (9-11). Furthermore, carcinoembryonic antigen the colon cancer patients and the matched patients. (CEA) is a new marker of CRA which was originally found to be expressed in the fetal intestine, liver, and pancreas Methodology at 8-20 weeks in adults when tumors manifest. Positive serum CEA is present in gastrointestinal tumors and is Yunnan Cancer Hospital collected all cases of diagnosed found in 70% to 90% of patients with CRA (12). Similar CRA from 2013 to 2018, and these cases were compared tumor antigens include carbohydrate antigens (CA) such as according to gender, age group, ethnic group, and regions. CA50, CA19-9, CA242 and CA724 (13,14). However, these genetic screening techniques are not yet widely available Grouping for screening for CRC prevention due to the immature technology and substandard medical level in Yunnan. Cases were divided according to gender into male and CRA has become a public health problem in China, female groups. By age, cases were divided into 3 groups: owing to the changes seen in modern lifestyles and dietary those under 40 years of age, those aged between 40 and 60 habits, with its rapidly rising incidence and mortality. years of age, and those above 60 years of age. According to China is a multi-ethnic country with more than 1.3 billion the prefecture group, there were a total of 16 geographical people and 56 ethnic groups, and Yunnan is a region groups: 8 prefecture-level cities in Yunnan (Kunming, that contains 25 of them. Most of the ethnic groups have Qujing, Yuxi, Zhaotong, Baoshan, Lijiang, Pu’er, and their social settlements, unique customs, and lifestyles. Lincang), and 8 autonomous prefectures (Dehong Dai Such a special population composition enables systematic Jingpo Autonomous Prefecture, Dali Bai Autonomous research on CRC to be performed in Yunnan taking into Prefecture, Chuxiong Yi Autonomous Prefecture, Honghe account socio-cultural and biological factors, which have Hani and Yi Autonomous Prefecture, Wenshan Zhuang great practical significance for the effective prevention and and Miao Autonomous Prefecture, Xishuangbanna early diagnosis of CRC. In this study, 1,016 cases of CRC Dai Autonomous Prefecture, Nujiang Yi Autonomous © Translational Cancer Research. All rights reserved. Transl Cancer Res 2020;9(4):2692-2700 | http://dx.doi.org/10.21037/tcr.2020.02.63 2694 Wan et al. Epidemiology characteristics of ethnic minority CRC in Yunnan in Southwestern China Racial and gender distribution of 1016 patients with colorectal cancer 600 510 500 400 389 300 200 100 29 14 15 7 8 5 5 5 7 3 3 10 4 0 2 Han Yi Bai Hani Dai Hui Miao Else Male Female Figure 1 1,016 colorectal cancer patients of Yunnan Cancer Hospital from 2013 to 2018. Else: Jingpo, Yi, Zhuang, Naxi, Laz, Pumi, Buyi and Yi. Prefecture, and Diqing Tibetan Autonomous Prefecture). incidence. Furthermore, more significance was shown in ethnic minority groups, and the incidence rates of different age groups were also different and statistically significant Statistical methods (P<0.05) (Tables 1 and 2). Data were processed by Epidata 3.1 for entry and grouping, The distribution of 113 CRC cases (4 of the 117 cases and statistical analysis was performed by SPSS 17.0. The were in Guizhou) among ethnic minorities in Yunnan is comparison between the data groups was performed by the shown in Figure 2: 66 cases (58%) were in western Yunnan, 2 x test, and P≤0.05 was considered statistically significant. 21 cases (19%) in southern Yunnan, 10 cases (9%) in central Yunnan, 9 cases (8%) in eastern Yunnan, and 7 cases in Results Guizhou (6%).