结肠、直肠癌是常见的恶性肿瘤,约占人类癌瘤的3～5%。在胃肠道癌瘤中,其发病率仅次于胃、食道,而居第三位。治疗结肠、直肠癌的关键是早期诊断。如能早期诊断、及时治疗,结肠癌是除皮肤癌以外治愈率最高的一种癌症,较胃癌约高3倍以上。但因病程进展缓慢,早期症状多不明显,且往往与其他普通疾病的症状相混淆,没有引起病人和医生的足够重视,所以误诊和迟诊率 Colon and rectal cancer are common malignancies and account for about 3 to 5% of human cancers. In gastrointestinal cancer, its incidence is second only to the stomach and esophagus, and it ranks third. The key to the treatment of colon and rectal cancer is early diagnosis. If early diagnosis and prompt treatment are available, colon cancer is the most cured cancer except for skin cancer, which is about 3 times higher than gastric cancer. However, due to the slow progression of the disease, many early symptoms are not obvious, and are often confused with the symptoms of other common diseases, and do not cause patients and doctors enough attention, so the misdiagnosis and delayed diagnosis rate