br included into the left sided colon
included into the left-sided colon cancer (LCC) group and the remaining 699 patients were assigned to the rectal cancer (RC) group. Clinicopathological features such as gender, age, pathological differentiation, neurovascular invasion, TNM stage, related tumor markers, maximum tumor diameter (MTD), median survival time and overall survival rate were extracted and analyzed.
Results: Patients in the RCC group had the oldest age of onset, highest positive rate of serum CA199 and greatest number of MANUSCRIPTpoorlydifferentiatedadenocarcinomasamong the three groups and significant statistical differences were found. The RC group had
the highest positive rate of vascular invasion (42.9%) and the greatest number of patients in stage I and IV (19% and 3.9%, respectively). Besides, the number of patients with stage T1-T2 adenocarcinoma in RC group was also the highest among the three groups. There were no significant differences in gender, perineural invasion as well as serum levels of CEA, CA724 and CA242. The median survival time of RCC, LCC and RC were 72, 70 and 73 months, respectively, with significant inter-group differences ( =0.049).
Conclusion: The age of onset of right-sided colon cancer is the oldest on average and poorly differentiated tumors accounted for the highest proportion. Besides, average maximum tumor diameter is the largest in right-sided colon cancer. In terms of median survival time, LCC is worse than RCC and RC. Colorectal cancer at different anatomical subsites has different epidemiological, clinicopathological features and prognosis. Fully understanding the clinicopathological features of colorectal cancer at different anatomical subsites is of certain guiding significance for the clinical diagnosis and treatment of colorectal cancer, and is conducive to individualized treatment and accurate treatment.
Key words: Colorectal cancer, Right-sided colon cancer, Left-sided colon cancer, Clinicopathological features
Colorectal cancer is one of the most common malignant tumors of the digestive tract. A recent study estimated that SP600125 there were more than 1.8 million new cases of colorectal cancer worldwide in 2018, ranking third in malignant tumors. Colorectal cancer causes
approximately 881,000 deaths every year, ranking second in malignant tumors. The latest cancer statistics in China in the year 2015 reported that there were about 376,000 cases of CRC in China, including 216,000 males and 160,000 females, ranking the fifth and the fourth respectively in the reported incidence of all malignant tumors. The number of new cases in cities is higher than that in rural areas (263,000 and 113,000, respectively). The number of deaths reached 191,000, including 111,000 males and
80,000 females, both of whom ranked theMANUSCRIPTfifthinmalignanttumors.Thehigh-riskage of CRC patients in China is between 60-74 years old with about 155,000 new cases,
accounting for 41.2% of all new cases. In recent years, more and more studies have discovered that there are differences in clinicopathological features and molecular biology between left and right-sided colon cancer, indicating that they are two different diseases of the same organ[3-5]. Michal Mik et al. showed that the average age of onset of patients with RCC was older (67.8 ± 11.3 years vs 63.2 ± 11.2 years; = 0.0087), and maximum tumor diameter was larger than that of patients with LCC (55 ±
60 mm vs 38 ± 21 mm; P = 0.0003). There are also differences in survival, prognosis and treatment response of colorectal cancer at different anatomical subsites. Compared with LCC, RCC usually has poorer pathological differentiation, higher lymph node metastasis rate, lower 5-year overall survival rate and disease-free survival rate. The mechanisms in the tumorigenesis of left-sided and right-sided colon cancer are also different. LCC is associated with known gene types, such as CIN, p53, NRAS, miRNA-146a, miRNA-147b and miRNA-1288, while RCC is associated with MMR, KRAS, BRAF and miRNA-31. This article analyzes the epidemiological and clinicopathological features of 1315 patients with colorectal cancer in order to provide more evidence for clinical diagnosis and treatment of colorectal cancer.
1 Materials and Methods
1.1 General profile
Retrospective analysis of 1315 patients with colorectal cancer who underwent surgery in the department of gastrointestinal surgery at the Second Affiliated Hospital of Dalian Medical University from January 2013 to January 2019. All patients were diagnosed with colorectal cancer by colonoscopy before surgery and then confirmed
with adenocarcinoma by postoperative pathological examination.
Inclusion criteria: primary colorectal cancer; pathologically confirmed adenocarcinomas; no preoperative radiochemotherapy; patients underwent radical or palliative resection; no perioperative death. Exclusion criteria: metastatic colorectal cancer or recurred colorectal cancer; pathologically diagnosed squamous cell carcinoma, carcinoid and neuroendocrine tumors; endoscopic resection.