Cancer of the colon and rectum

Cancer of the colon and rectum

Frequency

    • Cancer of the colon and rectum is one of the most common forms of malignant human tumors.
    • In the bulk of European countries and in Russia, these carcinomas in total take 6th place in the aftermath of cancer of the stomach, lung, breast, female genital organs and tends to further increase
    • More than 60% of colorectal cancer cases occur in the distal colon. In recent years, there has been a trend towards an increase in the number of patients with cancer of the proximal colon.
    • The peak incidence is over 60 years of age. Risk factors
    • Diet
    • A high content of meat in the diet (the increase in cases of colorectal carcinomas in developed countries is facilitated by an increase in the dietary content of meat, especially beef and pork, and a decrease in fiber) and animal fat accelerates the growth of intestinal bacteria that produce carcinogens. This process can be stimulated by bile salts. Natural vitamins A, C and E inactivate carcinogens, and turnip and cauliflower induce the expression of benzpyrene hydroxylase, which can inactivate absorbed carcinogens
    • There has been a sharp decline in cases among vegetarians
    • High frequency of colonorectal carcinomas among workers in asbestos industries, sawmills
    • genetic factors. The possibility of hereditary transmission proves the presence of familial polyposis syndromes and an increase (3-5 times) in the risk of developing colorectal carcinoma among first-degree relatives of patients with carcinoma or polyps (see Appendix 2. Hereditary diseases: / sorted phenotypes)
    • Other risk factors
    • Ulcerative colitis, especially pancolitis, and disease older than 10 years (10% risk)
    • Crohn’s disease
    •  Cancer, adenoma of the large intestine in history
    • Polyposis syndrome: diffuse familial polyposis, solitary and multiple polyps, villous tumors
    • History of female genital or breast cancer
    • familial cancer syndromes
    • Immunodeficiency states.

Classifications and staging

    • Macroscopic forms of colon and rectal cancer
    • Exophytic – tumors that grow into the intestinal lumen
    • Saucer-shaped – oval-shaped tumors with raised edges and a flat bottom
    • Endophytic – tumors that infiltrate the intestinal wall, do not have clear boundaries
    • Histology
    • Adenocarcinoma of varying degrees of maturity predominates (60% of cases)
    • Mucous cancer (12-15%)
    • solid cancer

(10-12%)

    • Squamous cell carcinoma and glandular squamous cell carcinoma: not common
    • TNM classification (see also Tumor, staging)
    • T, – the tumor occupies 1/3 of the circumference of one anatomical section of the intestine (or less) and does not infiltrate the muscular membrane
    • T2 – the tumor occupies more than 1/3, but less than 1/2 of the circumference of one anatomical section of the intestine, infiltrates the muscular membrane, but does not cause restriction of rectal displacement
    • T3 – the tumor occupies more than 1/2 of the circumference of one anatomical part of the intestine or limits its displacement, but does not infiltrate the surrounding structures
    • T4 Tumor infiltrates structures surrounding the rectum
    • Dybks classification as modified by Estler and Camera (1953)
    • Stage A. The tumor does not extend beyond the mucous membrane
    • Stage Vg The tumor invades the muscle, but does not affect the serous membrane. Regional lymph nodes are not affected
    • Stage B2. The tumor sprouts the entire wall of the intestine. Regional lymph nodes are not affected
    • Stage CG Regional lymph nodes affected
    • Stage C2. The tumor grows into the serosa. Regional lymph nodes affected
    • Stage D. Distant metastases (mainly to the liver).

The clinical picture depends on the location, size of the tumor and the presence of metastases.

    • Cancer of the right colon causes anemia due to slow chronic blood loss. It is not often that a tumor-like infiltrate is determined in the abdominal cavity and abdominal pain appears, but due to the large diameter of the proximal colon and liquid intestinal contents, acute intestinal obstruction develops quite infrequently and in the later stages of the disease.
    • Cancer of the left sections of the colon is manifested by violations of the functional and motor activity of the intestine. The small diameter of the distal colon, dense feces and frequent circular lesions of the intestine by the tumor predispose to the development of intestinal obstruction. A pathognomonic sign of colon and rectal cancer is pathological impurities in the stool (dark blood, mucus).
    • Hematogenous tumor metastasis traditionally involves the liver; possible damage to the bones, lungs and brain.

Carcinoid tumors are neuroepithelial tumors arising from argentaffinocytes (Kulchitsky cells) and elements of the nerve plexuses of the intestinal wall (see also Cyrcinoid Tumor, Carcinoid Syndrome). Colon carcinoid tumor is a rather rare disease (within 2% of all gastrointestinal carcinoids). More often they appear in the appendix, jejunum or rectum.

    • The likelihood of malignancy of carcinoid tumors depends on their size. Tumors < 1 cm in size are malignant in 1% of cases, 1-2 cm in size – in 10% of cases, >2 cm in size – in 80% of cases
    • Carcinoid tumors have a longer course than cancer. The process begins in the submucosal layer, then spreads to the muscular membrane. The serous and mucous membranes are affected much later
    • Carcinoids have the ability to metastasize to regional lymph nodes and distant organs (liver, lungs, bones, spleen).

Tumors of the appendix

    • Carcinoid tumors
    • Adenocarcinoma
    • Mucocele (retention, or mucous, cyst). Perforation of the cyst or contamination of the abdominal cavity during its resection can lead to the development of peritoneal pseudomyxoma, an infrequent disease characterized by the accumulation of a large amount of mucus in the abdominal cavity.

Other neoplasms (benign and malignant) of the colon are noted quite infrequently

    • From lymphoid tissue – lymphoma and lymphosarcoma
    • From adipose tissue – lipoma and liposarcoma
    • From muscle tissue – leiomyoma and leiomyosarcoma.

Squamous cell carcinoma of the anus is an uncommon malignancy; manifested by bleeding, pain, tumor formation and changes in intestinal motility. Treatment is surgical, the level of 5-year survival is 60%. Cloacogenic carcinoma is a carcinoma of the transitional epithelium in the dentate line of the anal canal; accounts for 2.5% of all anorectal carcinomas; occurs at the junction of the ectoderm and endodermal cloaca – a blind caudal stretching of the hindgut, more often in women (in a ratio of 3: 1), the age peak is 55-70 years. Treatment is surgical, after radiation therapy.

Diagnostics

    • Rectal examination is most informative for rectal cancer. Finger examination allows you to determine the presence of a tumor, the nature of its growth, connection with adjacent organs
    • Irrigoscopy (contrast examination of the colon with barium) allows you to determine the location, extent of the tumor and its size
    • Endoscopy with biopsy – sigmoidoscopy and colonoscopy clarify the localization of the colon tumor; histological conclusion establishes its morphology
    • Endorectal ultrasound (for rectal cancer) allows you to determine the germination of the tumor in adjacent organs (vagina, prostate gland)
    • KG, ultrasound, liver scintigraphy. Carried out to exclude frequently recorded distant metastases to this organ
    • If acute intestinal obstruction is suspected, a plain radiography of the abdominal organs is necessary.
    • Laparoscopy is indicated to exclude the generalization of the malignant process.
    • Test for occult blood. In patients at increased risk, guaiac test for fecal occult blood should be performed frequently and carefully examined for unexplained blood loss.
    • The determination of carcinoembryonic Ag is not used for screening, but the method can be used in the dynamic observation of patients with a history of colon carcinoma; elevated titer indicates recurrence or metastasis.

Treatment. Surgery for colon cancer is the method of choice. The choice of the nature of surgical intervention depends on the localization of the tumor, the presence of complications or metastases, the general condition of the patient. In the absence of complications (perforation or obstruction) and distant metastases, a radical operation is performed – removal of the affected sections of the intestine along with the mesentery and the regional lymphatic apparatus.

    • Types of surgery for colon cancer
    • For cancer of the right half of the colon – right-sided hemicolectomy with the imposition of ileotransverse anastomosis
    • In case of cancer of the middle third of the transverse colon – resection of the transverse colon with the imposition of stakes within the anastomosis

end to end

    • For cancer of the left half of the colon – left-sided hemicolectomy with the imposition of transverse sigmoid anastomosis
    • For cancer of the sigmoid colon – resection
    • In case of an inoperable tumor or distant metastases, palliative operations are performed to prevent complications (intestinal obstruction, bleeding): ileotransverse anastomosis, transversosigmoanastomosis, double-barreled ileo- or colostomy.
    • Types of operations for rectal cancer
    • If the tumor is located in the distal part of the rectum and at a distance < 7 cm from the edge of the anus at any stage of the disease (regardless of the anatomical type and histological structure of the tumor) – abdominoperineal extirpation of the rectum (Miles operation)
    • Sphincter-preserving operations can be performed with the localization of the lower edge of the tumor at a distance of 7 cm from the edge of the anus and above.
    • Anterior resection of the rectum: performed with tumors of the upper ampulla and rectosigmoid sections, the lower pole of which is located at a distance of 10-12 cm from the edge of the anus
    • With malignant polyps and villous tumors of the rectum, economical operations are performed: transanal excision or electrocoagulation of the tumor through a rectoscope, excision of the intestinal wall with a tumor using colotomy.
    • Combined treatment
    • Preoperative radiotherapy for rectal cancer reduces the biological activity of the tumor, reduces its metastasis and the number of postoperative relapses in the area of ​​surgical intervention
    • The role of chemotherapy in the treatment of colon cancer is not fully understood.

Diet. In the postoperative period, diet No. 0 is prescribed. Prognosis. The overall 10-year survival rate is 45% and has not changed significantly in recent years. For cancers limited to the mucosa (often detected by occult blood testing or colonoscopy), the survival rate is 80–90%; with tumors limited to regional lymph nodes – 50-60%. The main factors affecting the prognosis of surgical treatment of colon cancer: the prevalence of the tumor around the circumference of the intestinal wall, the depth of germination, the anatomical and histological structure of the tumor, regional and distant metastasis

    • After liver resection for isolated metastases, the 5-year survival rate is 25%
    • After lung resection for isolated metastases, the 5-year survival rate is 20%. Colon tumor recurrence
    • Determination of the content of carcinoembryonic Ag is a method for diagnosing recurrence of colorectal cancer. The titer of carcinoembryonic Ag is determined after 3 months during the first 2 years after the operation. With a persistent increase in the content of carcinomabrionic antigen, it will be necessary to examine the patient for the presence of metastases
    • Colon cancer recurrences often cause intense pain, exhaustion, and are very difficult to treat.
    • Surgery for recurrence of a tumor of the colon is traditionally palliative in nature and is aimed at eliminating complications (intestinal obstruction)
    • The positive effect of chemotherapy remains in doubt
    • Radiotherapy is palliative in nature.

See also Tumor, radiotherapy; Tumor, markers; Tumor, methods of treatment; Tumor, stages; Polyps intestinal ICD

    • C18.8 Malignant n/r with colon involvement extending beyond one or more of the above sites
    • C18.9 Malignant neoplasm of colon, site unspecified
    • C19 Malignant neoplasm of rectosigmoid junction
    • C20 Malignant neoplasm of rectum
    • C21 Malignant neoplasm of anus and anal canal

Literature. Korinek V et al: Constitutive transcriptional activation by a beta-catenin-Tcf complex in APC-/- colon carcinoma. Science 275: 1784-1787, 1997; Peifer M: Cancer, catenins, and cuticle pattern: a complex connection. Science 262: 1667-1668, 1993; Rubinfeld In et al: Stabilization of beta-Catenin by genetic defects in melanoma cell lines. Science 275: 1790-1792, 1997; Tumors of the colon: prevention and timely treatment. Timofeev YuM, Kotov VA. M.: OIC RAMN, 1996

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