intestinal tumor



OVERVIEW

Definition

The intestine refers to the digestive tube that exits from the lower end of the stomach to the anus, including the small intestine and large intestine.

The small intestine is divided into the duodenum, jejunum and ileum. The large intestine is divided into cecum, appendix, colon, rectum and anal canal.

Intestinal tumors are broadly defined as all tumors occurring in the human intestine, including benign and malignant tumors [1].

Strictly speaking, intestinal tumors also include malignant tumors that metastasize to the intestinal tract from other parts of the body, but the nature of metastatic tumors is mostly related to the tumors in the primary site, and the treatment and prognosis are also greatly affected by them, therefore, if not otherwise specified, the intestinal tumors mentioned in this paper refer to tumors originating in the intestinal tract.

Generally speaking, benign tumors and early malignant tumors have a better prognosis, while middle and late malignant tumors have a worse prognosis.

Classification

Classification according to site

The treatment and prognosis of colorectal tumors vary according to the site of occurrence. For example, malignant tumors of the large intestine usually have a better prognosis than malignant tumors of the small intestine.

Small bowel tumors

Refers to tumors that occur in the small intestine, including duodenal tumors, jejunal tumors, and ileal tumors.

Tumors of the Large Intestine

Tumors that occur in the large intestine, including colon and rectal tumors.

According to the nature of lesion typing

Benign intestinal tumors and early malignant tumors can usually be cured by resection and have a better prognosis; however, the treatment of middle and late malignant tumors is more complicated and the prognosis is relatively poor.

Benign intestinal tumors

Benign tumors of small intestine: such as adenoma, smooth muscle tumor, lipoma, hemangioma, fibroma, misshapen tumor-like lesion, immunoproliferative benign tumors of small intestine of lymphoid tissue origin, lymphangioma, neurofibroma, nerve sheath tumor and ganglion cell neuroma.

Benign tumors of the large intestine: e.g., lipomas, fibromas, adenomas, and hemangiomas of the rectum or colon.

Malignant intestinal tumors

Generally include rectal cancer, colon cancer, small bowel cancer, intestinal sarcoma, lymphoma, etc.

Incidence situation

There is no specific data on the overall incidence of intestinal tumors, and the incidence of intestinal tumors in different sites and types is used as a reference [1-2].

Small bowel adenomas are a more frequent type of benign tumors of the small bowel, accounting for about 35%. They are mostly located in the duodenum and ileum. It can occur at any age and is more common in 40-60 years old. There is no significant difference in the incidence between men and women.

Intestinal hemangioma can occur in the small intestine and large intestine, accounting for about 10% to 15% of benign tumors of small intestine.

Small bowel cancer is rare, the incidence rate is about 2% of all malignant tumors of the digestive tract, the average age of onset is 65 years old, and there are usually more males than females, and the male to female ratio is about 3:2.

Small intestinal lymphoma accounts for 1% to 10% of all extranodal lymphomas and 7% to 25% of all small intestinal tumors; primary colorectal lymphoma has a lower incidence rate, accounting for only 0.2% to 0.6% of colorectal malignant tumors.

The incidence rate of colorectal cancer in China rises significantly from the age of 50, reaches a peak at the age of 75 to 80, and then declines slowly. However, colorectal cancer in young people under 30 years old is not rare.

Causes

Causes

The etiology of intestinal tumors is still not completely clear.

The development of intestinal tumors is a complex, multifactorial and multistep pathological process, and its specific pathogenesis has not been fully elucidated. Research has confirmed that both intrinsic genetic factors and extrinsic environmental factors play important roles.

High risk factors

The following factors may increase the incidence of intestinal tumors and are called risk factors.

Dietary factors

It is generally accepted that a long-term diet high in animal protein, high in fat and low in fiber is a high risk factor for intestinal tumors [3].

A high fiber diet may reduce the risk of small bowel cancer.

Lifestyle

Smoking and alcohol consumption can increase the risk of intestinal tumors.

Lack of physical activity, sedentary occupations, overweight and obesity, and poor bowel habits are risk factors for intestinal tumors.

Related Diseases

Colon Related Diseases

Ulcerative colitis, intestinal polyposis, and intestinal adenomas increase the probability of developing intestinal malignancies.

Patients with Crohn’s disease have a 4 to 20 times higher risk of colorectal cancer than the normal population.

Small bowel related diseases

Such as familial adenomatous polyposis, hereditary nonpolyposis colorectal tumors, Boyds-Yeager syndrome, MYH gene-related polyposis, cystic fibrosis, etc. have a significantly increased probability of inducing small bowel cancer.

Heredity

Familial inheritance has been reported as a causative factor for intestinal tumors.

Others

Chromosomal aberrations, viral infections, Helicobacter pylori infections, prolonged heavy radiation, and immunocompromised conditions can lead to the development of intestinal lymphoma.

Symptoms

Early stage of intestinal tumor has no obvious symptoms or atypical symptoms, such as nausea, abdominal distension and loss of appetite.

When the tumor grows to a certain degree, it has different clinical manifestations according to its different growth sites. The following is only a list of common symptoms, for more details, please refer to the entries of the corresponding diseases [4-5].

Common symptoms

Abdominal discomfort or pain

Abdominal pain can be caused by the increasing size of the tumor, compression of the surrounding tissues or nerves, accompanied by intussusception, intestinal obstruction, and so on.

Abdominal mass

It is a common symptom of intestinal tumors, and some patients can palpate the mass through abdominal palpation.

Change of bowel habit

Constipation, diarrhea, alternating between constipation and diarrhea or increased frequency of bowel movement may occur. For example, patients with rectal cancer may have frequent bowel movements and a sensation of anal falling, and may also have discomfort in the lower abdomen, wanting to relieve bowel movement very much, but feeling incomplete after bowel movement [6-8].

Changes in stool properties

As the tumor grows and obstructs the intestinal canal, the stool gradually becomes deformed and thin. In severe cases, it may lead to intestinal obstruction.

Blood and mucus in stool

Blood and mucus on the surface of stool, or even pus and blood stool.

Intestinal obstruction

May be manifested as abdominal pain, abdominal distension, vomiting, and cessation of defecation.

Gastrointestinal bleeding

There may be symptoms of acute blood loss such as vomiting blood, black stools, fresh blood stools and weakness, fatigue, dizziness, blurred eyes, pallor, cold hands and feet, cold sweat, palpitations, restlessness, rapid pulse and even fainting.

Other symptoms

Intestinal perforation

Abdominal pain often occurs suddenly, usually persistent and severe, often intolerable to the patient, and worsened by deep breathing and coughing.

Cachexia

Malignant intestinal tumors may cause consumption, loss of appetite, etc., leading to weakness with weight loss, emaciation and even inability to take care of oneself.

Consultation

Department of Medicine

Gastroenterology

Please consult the Department of Gastroenterology for symptoms such as abdominal pain, abdominal masses, changes in bowel habits and stool characteristics, intestinal obstruction, and blood in stool.

General Surgery

If you are diagnosed with an intestinal tumor that requires surgical treatment, you may choose to consult the Department of General Surgery, Department of Gastrointestinal Surgery or Department of Surgical Oncology.

Oncology

When patients are diagnosed with intestinal tumors and need anti-tumor treatment, they can go to the Department of Oncology to receive systematic and standardized treatment.

Preparation for medical treatment

Consultation: Registration, Preparation of Information, Frequently Asked Questions

Consultation Tips

When you visit the doctor, you may need to undergo relevant examinations. Please choose clothes that are easy to put on and take off, so that the doctor can conduct a physical examination.

Record the symptoms, duration and other relevant information for the doctor’s reference.

Preparation Checklist

Symptom checklist

Particular attention should be paid to the time of onset of symptoms, special manifestations, etc.

Have you recently had unexplained bloody stools, black stools and other symptoms?

Any unexplained abdominal pain, abdominal masses, bloating, vomiting, etc.?

Are there any changes in bowel habits, such as diarrhea, constipation, or alternating between constipation and diarrhea?

Is there any gradual deformation and thinning of stools?

Is there any unexplained weight loss?

Medical History Checklist

Is there a history of smoking?

Is the diet predominantly high in animal protein, fat and low fiber?

Is there a family history of intestinal tumors?

Are there any underlying diseases such as familial adenomatous polyposis, intestinal polyps, enteritis, Crohn’s disease, etc.?

Are there any drug or food allergies?

Checklist

Test results of the last six months, which can be brought to the doctor’s office

Laboratory tests: blood routine, stool routine + occult blood, blood biochemistry tests.

Imaging examination: abdominal ultrasound, abdominal X-ray, CT, MRI, PET-CT, etc.

Specialized examination: tumor markers, gastroenteroscopy, histopathological examination

Diagnosis

Diagnosis is based on

Medical history

The patient may have the following medical history:

History of familial adenomatous polyposis, intestinal polyps, enterocolitis, and Crohn’s disease.

A family history of intestinal tumors.

Chronic smoking, excessive alcohol intake, obesity, and low activity.

Chronic high animal protein, high fat and low fiber diet.

Clinical manifestations

Symptoms

Patients have no specific manifestations in the early stage, and in the later stage, symptoms such as abdominal pain, abdominal mass, change of bowel habit and change of fecal character, blood in stool, etc. may appear.

Signs

Early patients may have no obvious signs.

Patients with long-term blood in stool may have anemia such as pallor, weakness, fatigue, dizziness and tinnitus.

The doctor may insert a finger (often the index finger) into the patient’s anus to perform a rectal fingerprinting, and may be able to palpate an obvious mass or anal stenosis.

Patients with intestinal perforation causing peritonitis may show pressure, rebound pain, and muscle tension on palpation of the abdomen.

Auscultation of the abdomen to define changes in the hepatic turbidities can help aid in the diagnosis of bowel perforation.

Visualization of the abdomen may reveal abnormal signs such as abnormal abdominal elevation, bowel pattern and peristaltic waves.

Auscultation of bowel sounds that are diminished, absent, or hyperactive may help determine the condition.

Laboratory Tests

Routine tests

Blood routine: as patients with intestinal tumors often have gastrointestinal bleeding, anemia and so on may be found.

Urine routine: observe whether there is hematuria, combine with urinary imaging to know whether the malignant tumor invades the urinary system.

Stool routine + occult blood: to determine whether there are red blood cells, white blood cells and other abnormalities. It is valuable for the diagnosis of small amount of gastrointestinal bleeding. Mostly used for screening.

Biochemical examination: help to determine whether the liver and kidney functions are abnormal, whether there are electrolyte disorders, dyslipidemia, etc., and guide the next step of treatment.

Tumor marker examination

CEA, CA199, CA724 tumor markers, can help the auxiliary diagnosis of the disease, efficacy judgment and follow-up monitoring.

Other tests

Such as blood lactate dehydrogenase, uric acid, β2 microglobulin, human immunodeficiency virus antibody, alkaline phosphatase, blood sedimentation, etc., can help in the diagnosis of intestinal lymphoma [3].

Imaging

X-ray examination

Abdominal plain film is helpful in the diagnosis of intestinal perforation and intestinal obstruction.

X-ray barium meal examination: it can find nodules, ulcers, polyps and infiltrative lesions. Such as intestinal lymphoma can be seen through small intestinal lymphoma X-ray barium meal see the small intestine has more extensive lesions, duodenum, jejunum lesions are significant.

CT examination

It helps to determine the location, size and extent of tumor, especially when accompanied by intestinal obstruction, which is more diagnostic.

It can also help malignant intestinal tumors to carry out staging diagnosis, evaluate local invasion, lymph node metastasis and distant metastasis of the tumor, and provide a more reliable basis for surgery.

It is also the main examination tool for follow-up to evaluate the efficacy of treatment by comparing with previous imaging results.

MRI examination

Generally MRI is a routine examination program for rectal cancer. For patients with locally progressive rectal cancer, it helps to evaluate the effect of neoadjuvant therapy.

When liver metastasis is suspected by clinical or ultrasound/CT examination, liver enhancement MRI is generally required.

Positron emission computed tomography (PET-CT)

It is generally not routinely used, but can be an effective adjunctive examination for patients with complex disease whose distant metastases cannot be comprehensively evaluated by existing examinations.

Endoscopy

Through colonoscopy, small enteroscopy, duodenoscopy, etc., lesions in the lumen of the digestive tract can be directly observed, and biopsy under direct vision can be performed to clarify the etiologic diagnosis.

Intestinal ultrasound endoscopy can initially observe the level and depth of intestinal canal invaded by the tumor, and can observe the surrounding lymph nodes, which can help to determine the T-stage of malignant tumor.

Pathologic examination

Pathological examination is the most reliable method in the diagnosis of intestinal tumors, and it is the necessary basis for definite diagnosis and formulation of treatment plan. Specimens can be taken under colonoscopy for mucosal staining, which can significantly improve the detection rate of small lesions.

Staging

Benign intestinal tumors do not involve staging; staging of malignant intestinal tumors can help to formulate reasonable treatment plans, correctly evaluate the efficacy and judge the prognosis. The more common colorectal cancer staging is introduced here. For details, please refer to the staging section of each disease entry.

TNM staging

Currently, TNM staging of colorectal cancer is a staging system jointly developed by the International Union Against Cancer (UICC) and the American Joint Committee on Cancer (AJCC), which is mainly based on the three elements of T, N and M. The staging system is based on the following three elements: T, N and M:

T: represents the scope of primary tumor, mainly refers to the size of the primary tumor foci and the degree of extravasation, generally divided into T1~T4.

N: represents the situation of regional lymph node metastasis, including the number of metastases and regional scope, generally divided into N0~N3.

M: represents distant metastasis.

Special reminder: the larger the number after T and N, the more serious it is, and the more advanced the staging is; there is a special case of Tis, which refers to carcinoma in situ and belongs to the very early staging; N0 refers to no regional lymph node metastasis, and N2~N3 generally belongs to the late stage; M only has the difference between M0 and M1, the former is no distant metastasis, and the latter is distant metastasis, and M1 is regarded as the late stage.

Clinical staging

Based on the different TNM stages, the overall clinical stage (prognostic grouping) of the patient is finalized, which is indicated by the Roman letters I, II, III and IV. Combined according to TNM staging, colorectal cancer can be categorized into the following stages:

IIB stage T4aN0M0

Stage IIB

T4aN0M0

Stage IIC T4bN0M0

Stage IIC

T4bN0M0

Stage IIIA T1-2N1/N1cM0, T1N2aM0

Stage IIIA

T1～2N1/N1cM0, T1N2aM0

Stage IIIB T3 to T4aN1/N1cM0, T2 to 3N2aM0, T1 to 2N2bM0

Stage IIIB

T3 to T4aN1/N1cM0, T2 to 3N2aM0, T1 to 2N2bM0

Stage IIIC T4aN2aM0, T3 to T4aN2bM0, T4bN1 to N2M0

Stage IIIC

T4aN2aM0, T3 to T4aN2bM0, T4bN1 to N2M0

IV any T, any N, M1

Ⅳ

Any T, any N, M1

Differential diagnosis

Intestinal tumors should be differentiated from intestinal metastatic tumors, peptic ulcers, tuberculous colitis, hemorrhoids, and other diseases.

Intestinal metastatic tumor

Similarities: both may present with symptoms such as abdominal pain, abdominal mass, gastrointestinal bleeding, and intestinal obstruction.

Differences:

In addition to the above symptoms, it is often accompanied by primary tumor-related manifestations. For example, if cervical cancer metastasizes to small intestine, there may be symptoms such as irregular vaginal bleeding and vaginal discharge.

It needs to be clear that it is primary malignant tumor and not caused by direct invasion of primary foci, which is confirmed by caesarean section or specific examination and histology.

Peptic ulcer

Similarities: Small bowel cancer and peptic ulcer both have epigastric discomfort or pain, fever, positive fecal occult blood test.

Differences: Peptic ulcer can often be diagnosed by combining history, clinical manifestations, endoscopy and special examination results.

Tuberculous colitis

Similarities: Colorectal cancer and tuberculous colitis are both associated with mucous blood stools or pus-blood stools, increased frequency of stools or diarrhea.

Differences: Tuberculous colitis may be accompanied by symptoms of tuberculosis toxicity such as hot flashes, night sweats (abnormal sweating after going to sleep, which stops after waking up), fatigue, lack of appetite, and weight loss. Differential diagnosis can be helped by colonoscopy and physical examination.

Hemorrhoids

Similarities: The symptoms of both intestinal tumors and internal hemorrhoids include blood in the stool.

Differences: Patients with intestinal tumors often present with anorectal irritation. Anorectal fingerprinting or proctoscopy can usually differentiate them.

Treatment

Aim of treatment: benign tumors and early tumors should be cured; middle and late stage tumors should be treated mainly to relieve patients’ symptoms, control disease progression and improve patients’ quality of life.

Treatment principle: once the diagnosis of intestinal tumors is clear, timely attention should be paid to them; benign tumors can be selected for observation or treatment depending on the situation; malignant tumors should be operated or treated as early as possible. At present, surgery is the main treatment method, combined with chemotherapy, radiotherapy, molecular targeted therapy and interventional therapy and other multi-methods of comprehensive treatment.

Tips] For more information about treatment, please refer to the relevant disease articles.

Surgery

The treatment of intestinal tumors is mainly based on surgical resection.

Some benign intestinal tumors have the risk of malignancy and need to be treated with surgery.

The most effective treatment for malignant intestinal tumors to control disease progression is also surgical resection, especially radical resection.

The choice of surgical approach depends on the patient’s status, tumor size, growth pattern and site of occurrence.

Common surgical modalities include endoscopic resection (e.g., laparoscopic and argon ion beam coagulation) or laparoscopic surgery or open surgery, with feasible local resection of the tumor or local resection of intestinal segments or combined resection of the involved organs.

Chemotherapy

Chemotherapy is a systemic treatment that uses cytotoxic drugs to destroy cancer cells. Malignant intestinal tumors can be selected chemotherapy according to the situation, which can be broadly divided into postoperative adjuvant therapy, preoperative neoadjuvant chemotherapy and palliative chemotherapy.

Chemotherapy for colorectal cancer

The commonly used chemotherapy regimens are as follows [8-10]:

Modified FOLFOX6 regimen: oxaliplatin, calcium folinate, fluorouracil (5-FU).

CapeOX regimen: oxaliplatin, capecitabine.

Modified FOLFIRI regimen: irinotecan, calcium folinic acid, fluorouracil.

Targeted therapy-containing chemotherapy regimens: chemotherapy regimens containing irinotecan or oxaliplatin may be used in combination with bevacizumab, cetuzumab, or panitumumab.

Chemotherapy for small bowel cancer

Commonly used chemotherapy regimens are as follows [6-7,11]:

No standardized treatment regimen has been developed for small bowel cancer. The efficacy of postoperative chemotherapy is controversial.

Most of the chemotherapy regimens used are borrowed from those used for colon or gastric cancer, and most of them are based on fluorouracil-based drugs, with an emphasis on individualized chemotherapy regimens.

Chemotherapy for intestinal lymphoma

The CHOP regimen is mainly used, i.e., treatment with cyclophosphamide, doxorubicin, vincristine, prednisone, and patients are given rituximab immunotherapy when necessary to reduce complications such as perforation and bleeding [1].

Radiotherapy

Tumor radiation therapy, referred to as radiotherapy, is a local treatment that can be used to destroy and eradicate local primary tumors or metastatic lesions, and can be used to treat malignant intestinal tumors alone.

Rectal Cancer

Radiotherapy can shrink the tumor and improve the radical surgical resection rate; reduce lymph node metastasis; and reduce the chance of local recurrence.

Colon cancer

Radiotherapy is generally not used as a routine treatment. Patients with metastasis in supraclavicular lymph nodes or retroperitoneal lymph nodes have certain curative effect by applying local irradiation of radiotherapy [9].

Small bowel cancer

Except for small bowel sarcoma, which has some sensitivity to radiotherapy, most small bowel cancers are insensitive to radiotherapy and are usually not selected for radiotherapy, but for small bowel carcinoid tumors with multiple metastases in the liver, radiotherapy has a palliative effect [11].

Intestinal lymphoma

Because of its multifocal nature and its dissemination characteristics, radiotherapy tends to benefit less in clinical practice.

Targeted therapy

Targeted therapy is a therapeutic method that targets the specific (or relatively specific) molecules possessed by tumor tissues or cells, and uses molecularly targeted drugs to specifically block the biological function of the target, so as to achieve the therapeutic method of inhibiting the growth of tumor cells or even clearing the tumor.

Currently, commonly used molecularly targeted drugs in colorectal cancer include cetuximab (recommended for patients with wild-type KRAS, NRAS, and BRAF genes), bevacizumab, regorafenib, and furaquintinib [10].

For small bowel cancer, targeted therapies are still in the research phase at this stage and there is not much evidence available.

Immunotherapy

Tumor immunotherapy is the use of the body’s immune mechanism to enhance the patient’s immune function through active or passive methods to achieve the purpose of killing tumor cells, commonly used immune checkpoint inhibitors.

Navulizumab and pabolizumab, are commonly used in the treatment of patients with metastatic colorectal cancer with microsatellite instability and have better efficacy [12].

Interventional therapy

Arterial embolization chemotherapy has some therapeutic value for small bowel cancer with rich blood supply, but it is seldom used due to poor selectivity and high side effects, and it is mainly used for the treatment of liver metastasis of small bowel cancer.

Prognosis

Cure

Different types of intestinal tumors have different prognoses. Generally speaking, benign tumors are better cured than malignant tumors.

Small bowel cancer

The 5-year survival rate for all stages of small bowel cancer [7]:

55% for stage I.

49% for stage IIA and 35% for stage IIB.

Stage IIIA is 31% and stage IIIB is 18%.

Stage IV is only 5%.

Colorectal Cancer

The 5-year survival rate of colorectal cancer by stage [8]:

Stage I 90%～95%.

Stage II: 80%～85%.

Stage III 60%～70%.

Stage IV less than 20%. If you can receive radical surgery for metastases, the 5-year survival rate is about 40%.

Special reminder

The overall survival time of cancer patients can be roughly predicted by the 5-year survival rate, which refers to the proportion of patients whose tumors survive for more than 5 years after various comprehensive treatments. the probability of recurrence after 5 years is very low, and it can generally be regarded as a clinical cure.

Statistical data such as the 5-year survival rate are for clinical studies only and do not represent an individual’s specific survival period.

Survival should be analyzed in the light of the stage of the disease, physical condition, and whether the patient has received standardized treatment and regular follow-up, etc. Consultation with the physician is recommended.

Prognostic factors

Prognostic factors refer to a series of factors that may affect the patient’s survival time and quality of life. They include the clinical stage, the type of pathology, whether the treatment is timely and the physical quality of the patient.

Prognostic factors

The smaller the tumor diameter and the younger the patient, the better the prognosis.

The earlier the tumor is detected and treated, the better the prognosis.

Poor prognosis factors

Patients with incomplete resection have a poorer prognosis.

The larger the diameter of the tumor and the older the patient, the worse the prognosis.

Patients with deeper tumor infiltration have poorer prognosis.

Poor prognosis for lymph node and distant metastasis.

For small bowel cancer, patients with tissue type of adenocarcinoma have the worst prognosis.

For intestinal lymphoma, patients with systemic symptoms such as fever, night sweats and emaciation, involvement of the intrinsic muscular layer, and elevated blood lactate dehydrogenase and β2-microglobulin levels have a poorer prognosis [3].

Daily

Daily management

Dietary management

Reasonable arrangement of diet, pay attention to eat more nutrient-rich and easy to digest food.

More vitamin-rich fresh fruits and vegetables can be consumed to supplement the vitamins needed by the body and promote recovery.

Eat more protein-rich foods, such as eggs, milk, lean meat and fish.

Cold, raw, stimulating, pickled, fried and deep-fried foods, such as fried chicken and chili peppers, should be avoided.

Life management

Avoid exertion, regular work and rest, and ensure sufficient sleep.

Proper exercise is needed in daily life to improve physical fitness and avoid low immunity.

Maintain a healthy body weight and take appropriate activities, such as slow walking, tai chi, qigong and breathing exercises.

Psychological support

Maintain a good mood and mindset to face the disease positively.

Learn to confide in friends and family members to avoid excessive pressure, which may cause mental illness, and seek help from a psychiatrist if necessary.

Patients should establish a correct understanding of the disease, accept treatment positively, and do work and housework to the best of their ability during and after treatment, so as to reintegrate into their social roles.

Family members should provide adequate companionship to the patient, create a cozy family atmosphere, comfort the patient and help him/her to tide over the difficult times.

Disease monitoring

Patients should pay attention to daily observation of physical manifestations. If symptoms such as abdominal pain, abdominal mass, change in bowel habit and stool texture, blood in stool, etc. recur or worsen again, they should seek medical advice promptly.

Follow-up review

The main purpose of follow-up is to find out the recurrence or progression of the tumor in time and make timely intervention and treatment in order to increase the survival rate and improve the quality of life of the patients.

General follow-up includes medical history, physical examination, routine stool + occult blood, routine blood, routine urine, liver and kidney function, tumor markers, chest/abdominal/pelvic CT, endoscopy and so on.

The follow-up plan should be individualized based on this guideline to determine the optimal follow-up plan.

Prevention

Intestinal tumors are currently of unknown etiology and cannot be completely prevented, but depending on the possible causative factors, the following measures may help to reduce the incidence of the disease.

Prevention

Improvement of lifestyle

Reasonable dietary arrangement, more fresh vegetables, fruits and other foods rich in carbohydrates and crude fiber.

Actively treat underlying intestinal diseases such as ulcerative colitis, polyposis, adenoma and Crohn’s disease.

Adopt a good lifestyle, do not smoke, do not abuse alcohol, eat a balanced diet, participate actively in physical activities, control weight and prevent obesity.

Have regular medical checkups

People with underlying intestinal diseases, positive fecal occult blood and family history of intestinal tumors should actively treat the underlying diseases and undergo regular medical checkups.

Screening

There is no recognized screening method for small bowel cancer for the time being. For colorectal cancer, regular endoscopic screening is recommended. The frequency of screening varies according to whether one belongs to a high-risk group [8].

Those who meet any of the following are at high risk for colorectal cancer, while those who do not meet any of the following are at average risk.

First-degree relatives such as parents, children, and siblings have a history of colorectal cancer, including a family history of non-hereditary colorectal cancer and a family history of hereditary colorectal cancer.

I have a history of colorectal cancer.

I have a history of intestinal adenoma.