What Factors Increase Colorectal Cancer Risk?

Rectal cancer is a cancer from the dentate line to the junction of the rectal sigmoid colon. It is one of the most common malignant tumors of the digestive tract. Rectal cancer is low in location and is easily diagnosed by digital rectal and sigmoidoscopy. However, because of its location deep into the pelvic cavity, the anatomical relationship is complicated, the operation is not easy to be thorough, and the postoperative recurrence rate is high. Middle and lower rectal cancer is close to the anal canal sphincter, and it is difficult to keep the anus and its function during surgery. It is a difficult problem in surgery, and it is also the most debated surgical method. The median age of rectal cancer in China is about 45 years old. Incidence rates among young people are increasing.

Basic Information

English name: Carcinoma of the Rectum, rectal cancer, cancer of rectum
Visiting department: Oncology

Multiple groups: Around 45
Common locations: rectum
Contagious: no

Causes of rectal cancer

The cause of rectal cancer is still not very clear, and its incidence is related to social environment, eating habits, genetic factors and so on. Rectal polyps are also a high risk factor for rectal cancer. At present, it is generally recognized that excessive intake of animal fats and proteins, and insufficient dietary fiber intake are high risk factors for rectal cancer.

Clinical manifestations of rectal cancer

1. Early rectal cancer is mostly asymptomatic.

2. Rectal cancer growth

To a certain extent, changes in bowel habits, bloody stools, pus and bloody stools, severe after anxiety, constipation, diarrhea, etc.

3. stool

Gradually tapered, late stage obstruction, weight loss, and even cachexia.

4. Tumor

Urinary tract irritation symptoms occur when invading surrounding organs such as the bladder, urethra, vagina, fecal fluid from the vagina, pain in the crotch and perineum, and edema of the lower limbs.

Rectal cancer test

Digital rectal examination

It is a necessary test step to diagnose rectal cancer. About 80% of patients with rectal cancer can be found by digital rectal examination at the time of consultation. Hard, bumpy bumps can be touched; intestinal stenosis can be touched in late stages, and the bumps are fixed. Finger cuffs see filthy pus and blood with feces.

2. Rectal microscopy

Rectal microscopy should be performed after digital rectal examination, to assist diagnosis under direct vision, to observe the morphology, upper and lower edges, and distance from the anal margin, and to take tumor tissue for pathological section examination to determine the nature of the tumor and its degree of differentiation. It is located in the middle and upper rectum and cannot be touched by fingers. A sigmoidoscopy is a better method.

3. Barium enema, fiber colonoscopy

It is not helpful for the diagnosis of rectal cancer, so it is not listed as a routine test, and it is only used to exclude multiple colorectal tumors.

4. Pelvic magnetic resonance examination (MRI)

Knowing the location of the tumor and its relationship with the surrounding structures can help to accurately stage the clinical stage before surgery and formulate a reasonable comprehensive treatment strategy, such as surgery or radiotherapy first?

5. Abdominal and pelvic CT

You can understand the location of the tumor, its relationship with adjacent structures, and the presence of metastasis around the rectum and other parts of the abdominal cavity. It is important for staging of rectal cancer.

6. Chest CT or chest X-ray

Find out if there are metastases in the lungs, pleura, mediastinal lymph nodes, etc.

Rectal cancer diagnosis

In general, patients with fecal bleeding should be highly vigilant in clinical practice. Don't make a hasty diagnosis such as "dysentery" or "internal hemorrhoids". Further examination must be performed to exclude the possibility of cancer. For the early diagnosis of rectal cancer, attention must be paid to the application of digital rectal examination, rectoscopy or sigmoidoscopy. Pathological diagnosis can be obtained by microscopy.

Rectal cancer treatment

The treatment of rectal cancer requires surgery as the mainstay, combined with chemotherapy and radiotherapy.

(A) surgical treatment

Divided into radical and palliative.

Radical surgery

(1) Transabdominal perineal resection (Miles surgery) is suitable for lower rectal cancer less than 7 cm from the anal margin. The scope of resection includes the sigmoid colon and its mesentery, rectum, anal canal, levator ani, sciatic rectal fossa tissue and surrounding anus. The skin and blood vessels are ligated and cut under the root of the inferior mesenteric artery or the left colonic artery, and the corresponding para-arterial lymph nodes are cleaned. Make a permanent colostomy (anal prosthesis) on the abdomen. This surgical resection is complete and the cure rate is high.

(2) Transabdominal resection and extraperitoneal anastomosis, also called anterior rectal cancer resection (Dixon surgery), is suitable for upper rectal cancer at a distance of more than 12cm from the anal margin. The sigmoid colon and most of the rectum are removed in the abdominal cavity, and the peritoneum is free. The rectum below the fold is anastomosed outside the peritoneum with the sigmoid colon and the rectum incision. This surgery is less invasive and can retain the original anus, which is ideal. If the tumor is large and has infiltrated the surrounding tissue, it should not be used.

(3) Resection of rectal cancer with anal sphincter preservation Suitable for early rectal cancer 7 to 11 cm from the anal margin. If the cancer is large, the degree of differentiation is poor, or the upward major lymph vessels have been infarcted by cancer cells and there is lateral lymphatic metastasis, this surgical method is not completely removed, and it is still better to perform a combined transabdominal resection. The current anal sphincter-preserving rectal cancer anastomosis is performed by anastomosis, transabdominal low resection-transanal anastomosis, transabdominal free-transanal resection and anastomosis, and transabdominal resection. Select the specific situation.

2. Palliative surgery

If the local invasion of the cancer is severe or the metastasis is too extensive to cure, in order to relieve the obstruction and reduce the patient's pain, palliative resection can be performed. Limited incision of the intestinal segment with cancer is performed. (Hartma surgery). If it is not possible, only perform a sigmocolostomy, especially in patients who have been accompanied by intestinal obstruction.

(Two) radiation therapy

Radiotherapy plays an important role in the treatment of rectal cancer. At present, it is believed that the partial and later stage rectal cancer has a longer survival period after concurrent chemotherapy and radiotherapy before surgery than surgery and radiotherapy.

(Three) chemotherapy

For patients with rectal cancer with stage II and III pathology, postoperative chemotherapy is recommended. The total chemotherapy time is six months.

(D) Treatment of patients with metastasis and relapse

Treatment of local recurrence

If the scope of the local recurrence lesion is limited, and there is no recurrence or metastasis in other parts, surgical exploration can be performed for resection. In patients who have not previously undergone pelvic radiotherapy, recurrent lesions in the pelvic cavity can be treated with radiation to temporarily relieve pain.

2. Treatment of liver metastases

In recent years, many studies have confirmed that the surgical resection of rectal cancer with liver metastasis is not as pessimistic as originally thought. Liver metastasis occurs in patients with rectal cancer, whether coexisting with the primary tumor or after the primary tumor has been removed. If liver metastases can be completely removed, the survival rate can be improved. For a single metastasis, hepatic segment or wedge resection is feasible. For patients with multiple liver metastases that cannot be surgically removed, systemic chemotherapy can be used to reduce the tumor to the point where it can be surgically resected, and the same effect can be achieved. For some patients, palliative chemotherapy should be performed if the liver metastases cannot be reduced to a degree that can be resected even by intensive chemotherapy.

Patients without surgical resection were treated with systemic chemotherapy. If there is pain or bleeding obstruction caused by the metastasis site, corresponding palliative treatment measures such as radiotherapy, analgesics, and fistula can be used.