Early diagnosis method of colorectal cancer

The symptoms of colorectal cancer are generally not very obvious in the early stage, and advanced colorectal cancer often has clinical manifestations of varying degrees. At this time, as long as you are vigilant, ask about the medical history in detail, conduct a careful physical examination, and supplement with laboratory, endoscopic and X-ray examinations, it is not difficult to make a correct diagnosis. The following is a comprehensive introduction to these early diagnoses.

1. Medical history

A detailed medical history can often reveal the diagnosis of colorectal cancer. For those who are middle-aged or older and have unexplained weight loss, anemia, changes in bowel habits, mucus in stool, blood in stool, intestinal obstruction, etc., colorectal cancer should be considered. In order to detect colorectal cancer early, some people who have no obvious symptoms but have risk factors for colorectal cancer, such as those with a family history of colorectal cancer, those who have suffered from multiple colon polyposis, ulcerative colitis, Crohn's disease, chronic schistosomiasis, or those who have received pelvic radiotherapy or cholecystectomy, should be followed up and reexamined regularly.

2. Early diagnosis of colorectal cancer

As mentioned above, the incidence of colorectal cancer has been increasing year by year, with a high mortality rate, and the 5-year survival rate is closely related to the Dukes stage. Since the cause of colorectal cancer is unknown, the improvement of survival rate depends on secondary prevention, that is, early diagnosis of colorectal cancer. Early diagnosis includes two meanings: one is early detection, and the other is early diagnosis. At present, due to the widespread use of fiber colonoscopy, endoscopic pathological tissue sampling and biopsy have become very simple and easy, so it is not very difficult to diagnose precancerous lesions or early cancer. However, the early detection of colorectal cancer still faces many obstacles. The main reason is that the symptoms of early colorectal cancer are often hidden, and patients who come to the doctor are often in the late stage of cancer; in addition, there is currently a lack of specific laboratory examination methods for early cancer diagnosis.

3. Physical Examination

A comprehensive physical examination not only helps to correctly diagnose colorectal cancer, but also estimates the severity of the disease, the invasion and metastasis of cancer, and serves as a reference for formulating a reasonable treatment plan. Local signs should pay special attention to intestinal obstruction, abdominal mass, and abdominal tenderness. Since the vast majority of colorectal cancers occur in the rectum and sigmoid colon, a digital rectal examination should be essential. Whenever a patient has symptoms such as blood in the stool, changes in bowel habits, and deformed stools, a digital rectal examination should be performed. During the examination, find out whether the anus or rectum is narrowed, whether the finger cuff is stained with blood, and if a mass is touched, its location, shape, range of lesions, activity of the base, and its relationship with adjacent organs should be clarified.

The initial screening test for colorectal cancer requires not only sensitive and specific methods, but also simple, easy to use, economical and practical. So far, a variety of methods have been tried for experimental diagnosis of colorectal cancer, but most of them are difficult to meet the above requirements. This is because most diagnostic indicators only have average differences between colorectal cancer patients and control patients, but they are not specific, it is difficult to establish the diagnostic threshold of cancer, and they are often insensitive to early cancer. According to the colorectal cancer survey data worldwide, the initial screening tests currently used for surveys are mainly fecal occult blood tests and rectal mucus T antigen tests developed in recent years. In addition, the use of monoclonal antibodies to detect colorectal cancer-related antigens in blood or feces is being tried in a small range of survey populations.