1、Colon cancerEpidemiology3rd most common cancer in males and femalesAccounts for 11% of cancer deaths.In 2000, 130,200 cases (colon and rectum).Lifetime risk 6%.EpidemiologyRare before the age of 40y, rapid increase at 50y.At presentation 37% localized, 37% regional, 20% metastatic.1 and 5y survival

2、is 80% and 61% overall.IBD, FAP, HNPCC, are at inc riskascending colon 11%transverse colon 4%descending colon 9%sigmoid colon and rectum 76% World 50-60%25-30% Poland5year survivalIntroduction:Many colorectal cancers are thought to arise from adenomatous polyps in the colon. These mushroom-like grow

3、ths are usually benign, but some may develop into cancer over time.Polyps may be small and produce few, if any, symptoms. Regular screening tests can help prevent colon cancer by identifying polyps before they become cancerous. Your best chance for surviving colorectal cancer is detecting it early.

4、When found early, there is nearly a 90 percent chance for cure.Symptoms:There often are no symptoms of colorectal cancer in its early stages. Most colorectal cancers begin as a polyp. As polyps grow, they can bleed or obstruct the intestine. When the disease spreads, it is still called colorectal ca

5、ncer Symptoms:rectal bleedingblood in the stool or toilet after a bowel movementprolonged diarrhea or constipation a change in the size or shape of the stoolA change in bowel movement pattern that continues over time General discomfort in the abdomen (frequent gas pains, cramping pain, feeling of bl

6、oating or fullness) Vomiting Constant fatigue Chronic constipationRisk Factors: Age: Colorectal cancer is most common in people over 50. Family history: Your risk is higher with a family history (especially parent, sibling) of colorectal cancer, or adenomatous polyps. Personal history: Your risk is

7、higher with a personal history of inflammatory bowel disease (Crohns disease or colitis), colon cancer, or adenomatous polyps. Weight: Lack of physical activity and obesity are risk factors. Diet: A high-fat diet, particularly animal fats, may Increase your risk. Diets high in fruits and Vegetables

8、are thought to decrease your risk. diets high in red and processed meat, as well as those low in fiber, are associated with an increased risk of colorectal cancer. Individuals who frequently eat fish showed a decreased risk Cigarette smoking and alcohol: Your risk may be higher if you smoke or drink

9、 Physical inactivity: People who are physically active are at lower risk of developing colorectal cancer.Risk FactorsPolyps-Most cancers arise from them.Classified as neoplastic (adenomatous)which are benign or malignant, and nonneoplastic (hyperplastic, mucosal, inflammatory, hamartomaous).Adenomat

10、ous polyps found in 33% of people by age 50, 50% by age 70.Most lesions 2cm, 34% in severe dysplasia).TreatmentEndoscopic removal, surveillance every three years.Biopsy if it cant be removed.Surgery for those not amenable to safe polypectomy (large sessile villous lesions).TreatmentFungation, ulcera

11、tion, distortion are contraindications for polypectomy. Colectomy indicated for residual carcinoma, those at high risk for +LN despite complete polypectomy.+margin, poor diff, level 4, vascular, lymphatic invasion.Sessile polyp with invasive cancer should be considered for resection even if no high

12、risk pathologic features.Weigh all against pts medical condition of course.Hereditary Polyposis SyndromesAll have this in common: Multiple intestinal polyps, extraintestinal manifestations.FAP: 1-2% of colon cancer patients. A point mutation of APC gene on chromosome 5, band q21.Polyps found through

13、out the GI tract but most in colon. Symptoms manifest by ages 16-50.Cancer will develop in all by age 50.Familial Adenomatous Polyposis (FAP) Familial adenomatous polyposis (FAP) is a genetic condition where affected individuals will develop hundreds to thousands of polyps If a parent has FAP, each

14、child has a 50% (or, 1 in 2) chance of inheriting FAP. Each child also has a 50% chance of not inheriting FAP. FAP does not skip generations. Both males and females are equally likely to be affected. Therefore, if you have FAP, your children each have a 1 in 2 chance of having FAP. Hereditary Polypo

15、sis SyndromesGardners Syndrome: Variant of FAP. Colonic and extracolonic manifestations.Periampulary lesions, duodenal lesions, gastric polyps.Ocular, cutaneous, skeletal (retinal, mandible, jaw, teeth, sebaceous cysts).Desmoids, hepatoblastoma, thyroid cancer, Turcots syndrome (brain).Hereditary No

16、npolyposis SyndromesLynch I and II. Occurs five times more frequently than familial polyposis. 1-5 % of colon cancers. Lynch I just colon, Lynch II also involves endometrium, ovary, stomach, small bowel, biliary, pancreas, ureter, renal pelvis.85% lifetime risk of colon cancer, more right sided canc

17、ers (60-70%), earlier (45y), lower stage, better survival, but 20% risk of metachronous, synchronous lesions.Inflammatory Bowel DiseaseUlcerative colitis carries a risk of colorectal carcinoma 30 times greater than general population.Risk increases with duration of disease.After 30 years, risk incre

18、ases to 35%Crohns disease associated with 10-20 fold increased risk of cancer.Need to do surveillance in these population.Previous Colon CancerA second primary colon cancer is three times more likely to develop in patients with a history of colon cancer.Metachronous lesions develop in 5-8% of patien

19、ts.History of First-Degree RelativesPeople with first-degree relatives with colorectal cancer have a 1.8-8 fold increase risk of colorectal cancer.Risk is higher if more than one relative affected.Risk is higher if developed in the relative at a young age.Pathology90% adenocarcinomas. Four morpholog

20、ic variants.Ulcerative (most common), exophytic (polypoid, fungating), annular (classic applecore), submucosal infiltrative(linnitus type).Grading system 1-3. Most developed to least differentiated glandular structures.The Layers of the WallColon WallStagingA- to submucosa onlyB1- to muscularis only

21、 B2- thru wall, not adjacent. B3- Adjacent organs involved.C1- B1 plus LNC2- B2 plus LNC3- B3 plus LND- Distant metsA - 95 - 100 %B - 72 - 80%C - 26 - 34 %D - 0 - 2 %Staging-TNMT1 invades submucosaT2 invades muscularisT3 invades subserosaT4 invades organs outsideN1- 1-3 nodesN2- 4 or more nodesN3- c

22、entral nodesM0- no mets M1- distant metsClinical PresentationBleeding, pain, bowel habit changes, weight loss, anorexia, nausea, vomiting, fatigue, anemia.Right upper quadrant pain, fevers sweats, hepatomegaly, ascites, effusions, adenopathy(METS).Obstruction(5-15%) increases risk of death 1.4 fold.

23、Perforation (6-8%) increases it 3.4 fold.Stage I 15%, Stage II 30%, Stage III 20%, Stage IV 25%.Obstruction less common on right side.Liver MetsColon CancerDIAGNOSIS: Colorectal cancer screening rates remain low. Therefore, screening for the disease is recommended in individuals who are at increased

24、 risk. There are several different tests available for this purpose.Continue Digital rectal exam (DRE): The doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas. It only detects tumors large enough to be felt in the distal part of the rectum but is useful as an initi

25、al screening test. Fecal occult blood test (FOBT): a test for blood in the stool. Two types of tests can be used for detecting occult blood in stools i.e. guaiac based (chemical test) and immunochemical. The sensitivity of immunochemical testing is superior to that of chemical testing without an una

26、cceptable reduction in specifity.Endoscope: Sigmoidoscopy: A lighted probe (sigmoidoscope) is inserted into the rectum and lower colon to check for polyps and other abnormalities. Colonoscopy: A lighted probe called a colonoscope is inserted into the rectum and the entire colon to look for polyps an

27、d other abnormalities that may be caused by cancer. A colonoscopy has the advantage that if polyps are found during the procedure they can be immediately removed. Tissue can also be taken for biopsy. DiagnosisScope, Chest X-ray, Complete blood count, CEA, Localized Fibrous TumorsPreop CT scan? Some

28、get it for abnormal LFTs only (but only 15% of liver mets have abnormal LFTs). Others will get it if large bulky tumors to see about adjacent organs, LN.10% of mets are missed with preoperative and operative evaluations, IOUS best for this.Diagnosis15-20% liver mets not palpable.Preop CEA reflects p

29、rognosis, disease extent (over 10-20 poor)CEA may not be elevated in poorly differentiated or rectal cancers.CEA really only good for follow up.Rectal CancerIn addition to History&Physical, CXR, CBC, LFTs, EUS, Proctoscopic exam, full colonoscopy, CT scan should be done for rectal cancer.Accurate pr

30、eoperative staging critical because stage may influence treatment decisions such as trans anal excision, preop chemoradiation.Rectal CancerEUS is most accurate tool in determining tumor stage with all layers identified with 67-93% accuracy.Differentiating T1 from T3 easy but T2 from T3 harder.Limita

31、tions of EUS: operator experience, differentiating LN vs.blood vessels, post radiation changes, stenotic lesions, overstaging (10-15%), understaging (1-2%).Superior to CT or MRI for depth of tumor.Rectal CancerLymph node staging more difficult. EUS 62-83% accurate, CT scan 35-73% accurate.All these

32、tests pick up size of LN only.50-75% of involved LN are normal in size, so may not be picked up. Similarly, enlarged LN may be inflammatory, so false negative.LN 3mm and hypoechoic are likely to have malignancy, also FNA might help under EUS guidance.Rectal CancerCT scanning of abdomen and pelvis is

33、 important for other organ involvement, and distant spread.CT is better than EUS for contiguous organ involvement.Pathology:The pathology of the tumor is usually reported from the analysis of tissue taken from a biopsy or surgery. A pathology report will usually contain a description of cell type an

34、d grade. The most common colon cancer cell type is adenocarcinoma which accounts for 95% of cases. Other, rarer types include lymphoma and squamous cell carcinoma.Cancers on the right side (ascending colon and cecum) tend to be exophytic, that is, the tumour grows outwards from one location in the b

35、owel wall. This very rarely causes obstruction of feces, and presents with symptoms such as anemia. Left-sided tumours tend to be circumferential, and can obstruct the bowel much like a napkin ring.1-Surgery and treatment:Colectomy with Ileorectostomy (Ileorectal Anastomasis) In this procedure, the

36、colon is removed, but all or most of the rectum is left in place. The small intestine is attached to the upper portion of the rectum. Most patients maintain very good bowel function, though anti-diarrhea medications are sometimes needed. This procedure is typically recommended when there are very fe

37、w polyps in the rectum. . Restorative Proctocolectomy (Ileal Pouch Anal Anastomosis)This operation involves removing the entire colon and most of the rectum. A new rectum, or reservoir for stool, called a pouch, is made out of the lower end of the small intestine (ileum). The pouch is joined to the

38、anus so bowel movements can flow in the normal way. A temporary ileostomy, or a stoma where the waste empties into a bag through the abdominal wall, is usually needed to help heal this delicate connection. Restorative Proctocolectomy (Ileal Pouch Anal Anastomosis)Chemotherapy Chemotherapy is used to

39、 reduce the likelihood of metastasis developing, shrink tumor size, or slow tumor growth. Chemotherapy is often applied after surgery (adjuvant), before surgery (neo-adjuvant), or as the primary therapy (palliative). The treatments is to improve survival and/or reduce mortality rate, In colon cancer

40、, chemotherapy after surgery is usually only given if the cancer has spread to the lymph nodes (Stage III)Life Style and NutritionThe comparison of colorectal cancer incidence in various countries strongly suggests that sedentarily, overeating (i.e., high caloric intake), and perhaps a diet high in

41、meat (red or processed) could increase the risk of colorectal cancer In contrast, a healthy body weight, physical fitness, and good nutrition decreases cancer risk in general. Accordingly, lifestyle changes could decrease the risk of colorectal cancer as much as 60-80%. A high intake of dietary fibe

42、r (from eating fruits, vegetables, cereals, and other high fiber food products) has, until recently, been thought to reduce the risk of colorectal cancer Calcium or folic acid (a B vitamin), aspirin are able to decrease carcinogenesis in pre-clinical development models: Some studies show full inhibition of carcinogen-induced tumors in the colon of rats. ScreeningFOBT, DCBE, endoscopy most useful screening methods.FOBT detects cancer at an earlier stage, with reduction in cancer deaths.Flexible sigmoidoscopy and polyp clearance has resulted in decreased colon ca