With the change of lifestyle, the incidence of colorectal cancer has increased significantly and has become one of the most common gastrointestinal malignancies, which seriously threatens people’s health and quality of life. In China, 75%-80% of colorectal cancers are rectal cancers, and 75% of the rectal cancers are low rectal cancers.
As we all know, early detection and early treatment are the gold standard of all cancer treatment, but most people do not know enough about colorectal cancer. In fact, blood in stool is an early warning sign of colorectal cancer, especially rectal cancer, but it is often misdiagnosed as bleeding hemorrhoids or enteritis, with a misdiagnosis rate of 88.57% and an average misdiagnosis time of 8 months.
How to detect colorectal cancer at an early stage, the following examinations should be emphasized.
I. Rectal and anal finger retrieval
Anal finger examination is simple and easy to perform, and rectal finger examination is still the most basic and important examination method among a series of pre-surgery examinations for rectal cancer.
Laboratory examination
1.Fecal occult blood test: this method is simple and easy to use, and it is the initial screening method for colorectal cancer screening and routine examination of colon diseases. Immunological methods can also be applied to improve the correct rate if necessary.
2.Hemoglobin test: Any unexplained anemia with hemoglobin lower than 100g/L should be recommended for barium enema or fiber colonoscopy.
3.Serum carcinoembryonic antigen (CEA) test: CEA test does not have specific diagnostic value, so it is not suitable for screening or early diagnosis, but it is helpful for estimating prognosis, monitoring the efficacy and recurrence.
Endoscopy
Sigmoidoscopy or fiberoptic colonoscopy should be routinely performed for those who have blood in stool or change in stool habit and no abnormal findings by rectal examination. Endoscopy can observe the lesion under direct vision and take a biopsy for pathological diagnosis.
Fibrous colonoscopy is the most effective, safe and reliable examination method for the diagnosis of lesions in the large intestine, and most of the early colorectal cancers can be detected by endoscopy.
Double contrast imaging
Traditional barium enema X-ray examination often has difficulty in showing early stage cancer and colorectal adenoma, while double contrast imaging technology has greatly improved the detection rate and diagnostic accuracy of early colorectal cancer and small adenoma, and has become a routine examination in radiology department.
V. CT diagnosis
CT can not be used as a method of early diagnosis, but it is of great significance for the staging of colon cancer, especially for patients who are estimated to be inoperable but may be surgically resected after the application of external radiation or local intracavitary radiotherapy. The tumor can be directly observed invading the pelvic muscles (levator ani, internal olecranon, coccygeus, pear muscle, gluteus) bladder and prostate.
CT examination of the pelvis can be performed at 3 months after surgery as a base film for follow-up. In addition, CT can provide correct localization and determine the appropriate target volume for the application of radiotherapy for recurrent rectal cancer.
Ultrasonography
Endorectal ultrasonography is a new diagnostic method to detect the invasion of rectal cancer and the degree of infiltration of tumor into the rectal wall, and it has been used in clinical practice since 1983. Endorectal ultrasonography can correctly diagnose the invasion site and size of tumor.
Magnetic resonance examination
Some researchers claim that magnetic resonance examination (MRI) is more meaningful than CT for external invasion of rectal cancer. However, there are still many technical problems in MRI that need to be improved, and the understanding of the image provided by MRI also needs to be further deepened.