Colorectal Cancer in surgery.pptxakdkdjnd

Colorectal Ca

1. COLORECTAL CANCER BY BALUKU CHARLES BMS 4.2 KAYUNGA SITE 2025 2021-08-07778

2. COURSE OUTLINE: Anatomy of colon. Physiology Epidemiology Risk factors Spread of colon cancer Clinical presentation. Staging Management Follow up. Prognosis

3. ANATOMY of the colon The colon is approximately 1.5m long, inverted ,u shaped part of the large intestines.lower gastrointestinal tract. Extends from the caecum to the rectum. It is divided into the caecum, ascending colon, hepatic flexure, transverse colon with attached greater omentum, splenic flexure, descending colon, sigmoid and rectum. Embryologically, the colon develops the mid gut (ascending colon to proximal transverse colon) the hind gut (distal transverse colon to sigmoid colon.

4. Cont’d. The important posterior relations of the caecum and ascending colon are the right ureter, right gonadal vessels and duodenum and these must be protected at surgery. The left ureter, left gonadal vessels and tail of the pancreas must be protected when operating on the left colon.

5. Cont’d. The ascending colon lies vertically in the most lateral right part of the abdominal cavity, occupying the right iliac fossa, right lumbar region and right hypochondrium. The proximal blind end (pouch) of the ascending colon is called the cecum. It takes a right angled turn below the liver (right colic or hepatic flexure) and becomes the transverse colon which has a horizontal course from right to left, occupying the right hypochondrium, epigastrium and left hypochondrium.

6. Cont’d. The transverse colon again takes a right angled turn just below the spleen (left colic or splenic flexure) which is attached to the diaphragm by the phrenocolic ligament ) and becomes the descending colon which lies vertically in the most lateral left part of the abdominal cavity, occupying the left hypochondrium, left lumbar region and left iliac fossa. Splenic flexure is higher to hepatic flexure. The descending colon leads to the inverted V shaped sigmoid colon which then becomes the rectum at the S3 level. The sigmoid colon is so called because of its S shape.

7. Paracolic gutters Lateral to ascending and descending colon are the right and left paracolic gutters of the peritoneal cavity through which fluid/pus in the upper abdomen can trickle down into the pelvic cavity. Sigmoid colon It is part of the large intestine after the descending colon and before the rectum. Sigmoid means S shaped. The walls of the sigmoid colon are muscular and contract to increase the pressure inside the colon causing the stool to move to the rectum.

8. Blood supply Arterial supply . The blood supply is derived from branches of the superior mesenteric artery and the inferior mesenteric artery. Adjacent branches anastomose so there is usually a complete vasculature of the colon, named the marginal artery of Drummond. Flow between these two systems communicates via a marginal artery that runs parallel to the colon for its entire length. Ileocolic, right colic and middle colic arteries are branches of the superior mesenteric artery Sudeck critical point at the rectosigmoid junction

9. Blood supply Venous drainage . This usually mirrors colonic arterial supply, with the inferior mesenteric vein draining into the splenic vein, and the superior mesenteric vein joining the splenic vein to form the hepatic portal vein that then enters the liver.

10. Blood supply

11. Cont’d. Lymphatic drainage . The ascending colon and proximal two thirds of the transverse colon is to the colic lymph nodes and the superior mesenteric lymph nodes, which drain into the cisterna chili. The lymph from the distal one third of the transverse colon, the descending colon, the sigmoid colon and the upper rectum drain into the inferior mesenteric and colic lymph nodes. The lower rectum to the anal canal above the pectinate line drain to the internal iliac nodes. The anal canal below the pectinate line drains into the superficial inguinal lymph nodes.

12. PHYSIOLOGY OF THE COLON The principle function of the colon is absorption of water; 1000mL of ileal content enters the caecum every 24 hours, of which only approximately 200mL is excreted as faeces. Sodium absorption is efficiently accomplished by an active transport system, while chloride and water are absorbed passively. Absorption of nutrients including glucose, fatty acids, amino acids and vitamins can also take place in the colon. Colonic motility is variable. In general, faecal residue reaches the caecum 4 hours after a meal and the rectum after 24 hours. Passage of stool is not orderly because of mixing within the colon, so it is not uncommon for residue from a single meal to still be passed 4 days later.

13. EPIDEMIOLOGY Colorectal cancer is third most common cancer worldwide In the UK, colorectal cancer is the second most common cause of cancer death. Approximately 35000 patients are diagnosed with colorectal cancer every year in the UK. Approximately one-third of these tumors are in the rectum and two-thirds in the colon with a ratio of 1:1, male and female. Colorectal cancer occurs less frequently in the resource-poor world than in resource-rich countries .

14. Risk factors for colorectal cancer. Age > 50 Gender M>F Presence of adenomatous polyps. Personal h/o CRC or polyps. Positive family h/o polyps or CRC. Diet- red meat, fat and cholesterol and little fiber or fresh veggies. Lifestyle- smoking, alcohol, lack of exercise, obesity. Diabetes Inflammatory bowel diseases.

15. BENIGN COLORECTAL TUMORS Familial adenomatous polyposis. Its defined as presence of morethan 100 colorectal adenomaz 80% cases of pts have positive family hx and the reminder result from APC <adenomatous polyposis coli> found on the short arm of x-some 5. The risk for devt of colorectal cancer in lifetym is 100% 50% of pts with FAP have congenital hypertrophy of the retinal pigment layer and can be used as a diagnostic tool in absence of genetic test.

16. Extracolonic manifestations of FAM Endodermal derivatives; Hepatoblastoma fundic gland polyps adenomas and carcinomas of the duodenum, stomach,thyroid,biliary tree,small intestine. Ectodermal derivatives; epidermoid cyst pilomatrixoma CHRPE Mesordermal derivatives; osteomas desmoid tumors dental problems

17. DX Its usually dx at the age of 15 and polyps are always visible upto 30 yrs. CA of the bowel devps 10- 20 yrs after onset of polyps. Surgery z done at 17 or 18 years unless symptoms develop.

18. TREATMENT Surgery to prevent devt of colorectal carcinoma Surgical options are; - colectomy with ileorectal anastomosis - restorative proctectomy with an ileal pouch anal anastomosis -total proctectomy and end ileostomy

19. Lynch syndrome (hereditary nonpolyposis colorectal cancer) Its an autosomal dominant condition caused by a mutation in one of the DNA mismatch repair genes i.e MLH1 & MSH2. The risk of devt of colorectal carcinoma z 80% & the mean age of diagnosis z 45 yrs. DX HNPCC dx z reached by genetic testing or use of the Armsterdam2 criteria. Armsterdam2 criteria; 3 or more family members with HNPCC related cancers( colorectal,pelvis,endometrial,ureter , renal , smallbowel ) 2 successive affected generations. FAP excluded Atleast one colorectal ca dx b4 the age of 50 yrs Tumors verified by pathological examination.

20. MALIGNANT COLORECTAL CARCINOMA Colorectal cancer is a multifactorial disease process. Genetic factors, environmental exposures (diet) and inflammatory condition of digestive tract are all involved in development of colorectal cancer. .ETIOLOGY FAP HNPCC (Lynch syndrome) Diet Surgery Inflammatory bowel disease( UC & Crohn's disease) Obesity and lifestyle e.g smoking

21. ETIOLOGY CONT.. Hereditary nonpolyposis colon cancer (HNPCC, lynch syndrome ) Manifest at mean age of 44 years Lynch 1 is site specific, predisposes to colorectal only commonly right, poses about 40% life time risk for developing colorectal cancer, Lynch 2 individual with this syndrome are also at increased risk for urothelial cancer, endometrial cancer and other less common cancers . DIET Intake of red meat and particularly processed meat products ( haem and N-nitroso compounds). These adversely affect DNA in the colorectal mucosa.

22. Cont’d. Saturated fat increases the tumor promoting arachidonic acid and its metabolite on the cell membrane However fibre (vegetables, fruits ) containing calcium, vitamins (C,E) and fish offer a protective effect as by studies. The hypothesis is that increased roughage is associated with reduced colonic transit times, and this in turn reduces the exposure of the mucosa to dietary carcinogens. Surgeries Ileal resection, gastrostomies, cholecystectomy may marginally increase the risk of right sided colon cancer. Alter the enterohepatic cycle of bile acids, increasing bile acid pool in the bowel. The acid induces hyperproliferation of intestinal mucosa

23. Obesity and life style choices; such as cigarette smoking, and sedentary habits. Excess weight gain increases insulin and related hormones in blood encouraging cancer cell growth. Excess fat also creates an environment friendly for inflammation. Inflammatory bowel disease; such as UC and crohn disease also increases the risk of developing adenocarcinoma (inflammation of the colon can cause continuous turn over of cells hence high chances of irregularities leading to cancer.)

24. PATHOLOGY Macroscopically, four forms; The annular variety tends to give rise to obstructive symptoms, whereas the others present more commonly with bleeding. The four common macroscopic varieties of carcinoma of the colon: Cauliflower or proliferative: a bulky fungating tumor projects in the gut lumen, usually on right side Ulcerative: grows in the transverse axis of the bowel

25. Cont’d. Tubular: when annular spread longitudinal to involve segment 5cm and above. Annular: stenosing common on the left side, present with intestinal obstruction Microscopically , the neoplasm is a columnar cell adenocarcinoma. Origin from a benign polyp may be evident in early cases, before the benign architecture is destroyed by malignant infiltration.

26. Macroscopic varieties (annular ,tubular, ulcerative, cauliflower)

27. Distribution of colorectal cancer Most large bowel cancers arise from the left colon, notably the rectum (38%), sigmoid colon (21%), and descending colon (4%). Cancer of the caecum (12%) and ascending colon (5%) are less common, but may be gradually increasing in incidence. Cancer of the transverse colon (5.5%), flexures (2–3%) and appendix (0.5%) are relatively uncommon .

28. Distribution of colorectal ca .

29. SPREAD S pread locally or via the lymphatics, bloodstream or transcoelomically across the peritoneal cavity. Direct spread may be longitudinal or radial. Radial spread may be retroperitoneal into the ureter, duodenum and posterior abdominal wall muscles or intraperitoneal into adjacent organs or the anterior abdominal wall. In general, involvement of the lymph nodes by the tumour progresses from those closest to the bowel along the course of lymphatics to central nodes. However, this orderly process does not always occur.

30. Spread cont.. Haematogenous spread is most commonly to the liver via the portal vein. One-third of patients will have liver metastases at the time of diagnosis and 50% will develop them at some point, accounting for the majority of deaths. The lung is the next most common site; metastasis to ovary, brain, kidney and bone is less common. Colorectal cancer can spread from the serosa of the bowel or via sub peritoneal lymphatics to other structures within the peritoneal cavity including peritoneum, ovary and omentum .

31. Clinical features of colon cancer Clinical features depend on the time , location . Common in 8 th grade Familial type may present in young age group. Early ; Change in bowel habit (constipation ,diarrhea or alternate). Commonest symptom. Rectal bleeding (mostly left sided tumors of the colon) Abdominal pain.

32. On examination Late: O/E: abdominal tenderness, palpable abdominal mass, anemia, weight loss, hepatomegaly, ascites. Right sided growth commonly presents with anemia, palpable mass in the right iliac fossa, which is not moving with respiration, mobile, non tender, hard, well-localized with impaired tympanic note Left sided growth presents with colicky abdominal pain, altered bowel habits (alternating constipation and diarrhea), palpable lump, distension of abdomen due to obstruction. Later tenesmus with passage of blood and mucus

33. Sigmoid and rectum Rectal bleeding. Most important symptom Tenesmus: frequent urge to defecate. Spurious diarrhea Hemorrhoids due to obstruction to the superior rectal veins Involvement of adjacent structures Sacral pain when sacral plexus involved Fistula: rectovesical fistula , gastrocolic fistula. Tumor of t. colon invading the stomach Hydronephrosis

34. Investigations Laboratory, endoscopy , and radiological. Laboratory investigation. Baseline investigations to prepare for treatment CBC Liver function tests Renal function tests

35. Investigations Screening: faecal occult blood testing of people aged 60–69 years. Aguaiac based test detects peroxidase like activity of hematin in faecal occult blood ENDOSCOPY Detects colorectal ca in 70% of cases Sigmoidoscopy Colonoscopy

36. Cont’d. Colonoscopy and biopsy confirms the diagnosis It is usually possible to assess the bowel up to the splenic flexure, which will detect up to 70% of cancers and almost all that cause fresh rectal bleeding Colonoscopy is the investigation of choice if colorectal cancer is suspected

37. Colonoscopy.

38. Investigations cont.. RADIOLOGICAL STUDIES: Double-contrast barium enema has traditionally been used and shows cancer of the colon as a constant irregular filling defect and apple core deformity. It has now been largely replaced by computed tomography (CT) virtual colonoscopy, which is extremely sensitive in picking up polyps down to a size of 6mm.

39. Barium enema showing apple core appearance

40. Abd CT scan for sigmoid colon cancer

41. Staging of colon cancer A variety of staging systems are described for colorectal cancer based on pathological reporting to predict prognosis and guide adjuvant treatment. Dukes’ classification. Although it is simple and widely recognized, the more detailed TNM system is regarded as the international standard.

42. Dukes’ staging for colorectal cancer A: invasion of but not breaching the muscularis propria B: breaching the muscularis propria but not involving lymph nodes C: lymph nodes involved. D: metastatic disease. (5 year survival)

43. Astler-Coller classification Stage A: Limited to mucosa Stage B1: Extending into muscularis propria but not penetrating through it; nodes not involved. Stage B2: Penetrating through muscularis propria; nodes not involved. Stage C1: Extending into muscularis propria but not penetrating through it; nodes involved . Stage C2: Penetrating through muscularis propria; nodes involved. Stage D: Distant metastatic spread.

44. TNM classification for colonic cancer T: Tumour size T1: Into submucosa T2: Into muscularis propria T3: Into pericolic fat or subserosa but not breaching serosa T4: Breaches serosa or directly involving another organ.

45. TNM STAGING CONT.. N: Nodal involvement(regional lymph nodes) N0: No nodes involved N1: 1-3 nodes involved N2: 4 or more nodes involved M: Metastasis M0: No metastasis M1: Metastasis

46. TREATMENT Depends on the stage of the cancer. Treatment options including surgery, chemotherapy, radiotherapy. Surgery being the main stay. Potentially curative modality for localized colon cancer (stage I-III). Palliative if distant spread. PREOPERATIVE MANAGEMENT Preadmission counselling Prophylactic subcutaneous low molecular weight heparin, an tibiotics and bowel preparation through enemas, dietary restrictions .

47. Treatment cont.. Colectomy Right hemi colectomy: carcinoma of the caecum or ascending colon is treated by right hemi colectomy. Left hemi colectomy: this is the operation of choice for descending colonic, splenic flexural and sigmoid cancers Extended right hemicolectomy: carcinomas of hepatic flexure and transverse colon Techniques for the surgery;

48. Right and left hemicolectomy

49. Treatment cont.. Extended right hemi colectomy: Carcinomas of the transverse colon and splenic flexure are most commonly treated by an extended right hemi colectomy. The extent of the resection is from the right colon to the descending colon. Laparoscopic surgery.

50. Extended right hemicolectomy

51. Rectal cancers Should be preceded by neoadjuvant chemotherapy plus radiotherapy to downstage before surgery. Wide local incision for Duke A with 2cm margin for a tumor; less than 10cm from the anal verge Abdomial perineal resection for tumors less than 6cm. Adjuvant therapy includes the radiotherapy to reduce incidence of local recurrence Cytotoxic therapy, mayos regimen (5FU and lecovurine ) improves survival by 30%

52. Adjuvant therapy Chemotherapy for positive nodes, T4 lesions, venous spread, signet cell type, poorly differentiated, changes in CEA levels. Regimes are 5-fluorouracil, levamisole, irinotecan , capecitabine Radiotherapy usually no role as tumour is radio resistant often used in advanced tumours and inoperable recurrent tumours Prognosis depends on site of the tumour (left sided have better prognosis if seen early), type (colloid ca have better prognosis), size, age of patient, stage of tumour, presence of complications

53. Rectal cancer management Cancers arising in the distal 15cm of the large bowl share many of the genetic, biologic and morphologic characteristics of colon cancers. However, the unique anatomy of the rectum with its retroperitoneal location in the narrow pelvis and proximity to urogenital organs, autonomic nerves and anal sphincters makes surgical access relatively difficult. Biological properties of the rectum combined with its anatomic distance from the small intestine and its retroperitoneal pelvic location provides an opportunity for treatment by radiation therapy that is not feasible for colon cancers. Preoperative radiation is superior to postoperative radiation.

54. Cont’d. Preoperative radiation has many advantages Tumor down staging An increase in resection ability possibly permitting the use of sphincter sparing procedure. A decrease in tumor viability which may decrease the risk of reoccurrence. Preoperative radiation works better in well oxygenated tissues. Postoperatively tissues are relatively hypoxic as a result of surgery and maybe more resistant to radiation. Pre. op rad also minimizes the radiation exposure to small loops due to pelvic displacement and adhesions following surgery.

55. Cont’d. Disadvantages of pre. op rad Delay in definitive resection Possible over treatment of early stage i.e 1 and 2 Possible loss of accurate pathological staging. Increased postoperative complications, mobility and mortality rates secondary to radiation injury.

56. Transanal excision This is reserved for early stage cancers. The lesions amenable for local excision are small (< 3cm in size) occupying less than a third of a circumference of the rectum. There should also be no palpable or radiologic evidence of enlarged mesenteric lymph nodes. Preoperative endorectal ultrasound scan should be performed and if nodes are identified as suggestive of cancer, do not perform transanal excision.

57. Endocavitary radiation Here a larger dose of radiation can be delivered to a smaller area over a short period. Selection criteria for this procedure are similar to those of transanal excision. The lesion can be as far as 10cm from the anal verge and not larger than 3cm. TRANSANAL ENDOSCOPIC MICROSURGERY (TEM) TEM is another form of local excision that uses a special operating protoscope that distends the rectum with insufflated carbon dioxide and allows passage of dissecting instruments.

58. This method can be used on lesions located in the rectum and even in the distal sigmoid colon. SPHINCTER SPARING PROCEDURES. Procedures are described that use the traditional open technique. All these can be performed using laparascopic techniques. LOW ANTERIOR RESECTION (LAR) This is generally performed for lesions in the middle and upper third of the rectum and occasionally for lesions in the lower third. Because this is a major operation, patients who undergo LAR should be in good health. They should not be having preexisting sphincter problems or extensive pelvic disease.

59. Cont’d. Patients will not have a permanent colostomy but a temporally colostomy maybe necessary. The operation entails full mobilization of the rectum, sigmoid colon and usually the splenic flexure. Mobilisation of the rectum requires a technique called total mesorectal excision (TME) TME involves sharp dissection in the avascular plane that is created by the envelope that seperates the entire mesorectum from the surrounding structures which include the anterior peritoneal reflection and Denonvilliers fascia anteriorly and preserves the hypogastric plexus posteriorly and laterally.

60. COLO-ANAL ANASTOMOSIS (CAA) Very distal rectal cancers that are located just above the sphincter can be resected without the need for a permanent colostomy. The pelvic dissection is carried out down to below the level of the levetor ani muscles from within the abdomen. A straight tube coloanal anastomosis (CAA) can be performed using the double stapled technique. LAPAROSCOPIC RECTAL RESECTIONS

61. Abdominal Perineal Resection APR is performed in patients with lower third rectal cancers. APR should be performed in patients in whom negative margin resection will result in loss of anal sphincter function. This includes patients with involvement of the sphincters, preexisting significant sphincter dysfunction, or pelvic fixation, and sometimes is a matter of patient preference.

62. Postoperative mgt. LMW heparin should be continued for 28days postoperatively. Prolonged nasogastric drainage, intravenous fluid therapy and cautious introduction of oral fluid and diet represented traditional postoperative practice.

63. Metastatic disease Hepatic metastasis: 5-year survival of over 30% in resectable disease noted Liver surgeons are increasingly aggressive in treatment and the only absolute limitation on what can be resected relates to leaving behind sufficient functioning liver, although this clearly has to be moderated by patient factors. It is important not to biopsy potentially resectable hepatic metastases as this may cause tumor dissemination.

64. Emergency surgery cont.. For a left-sided lesion the decision lies between a Hartmann’s procedure or resection and anastomosis. Where endoscopic and radiological facilities are present an obstructing left-sided lesion can be treated with an expanding metal stent. This has the advantage of converting an emergency operation with a high chance of a stoma to a situation that can be managed semi-electively by resection and anastomosis.

65. Prognosis Overall 5-year survival for colorectal cancer is approximately 50%. The most important determinant of prognosis is tumour stage and, in particular, lymph node status. Patients with disease confined to the bowel wall (Dukes stage A) will usually have cure by surgical resection alone and over 90% will have disease-free survival at 5 years. Spread beyond the bowel wall (Dukes B) reduces 5-year survival to approximately 60–70%.

66. Prognosis cont.. Patients with lymph node metastases (Dukes C) have a 5-year su rvival of 30%, while fewer than 10% of patients presenting w ith metastatic disease at the outset will be alive 5 years later.

67. Follow up Follow-up aims to identify synchronous bowel tumors (present in 3%) that were not picked up at the time of original diagnosis due to emergency presentation or incomplete assessment. Similarly, 3% of patients will develop a metachronous (at a different time) colonic cancer and surveillance colonoscopy is designed to diagnose these. CEA (CARCINOGENIC EMBRYONIC ANTIGEN ) TO MONITOR FOR RECURRENCE

68. PREVENTION AND SCREENING Screening of population at risk (as early as 45 years) has shown to reduce colorectal cancer incidence through such investigations as DRR , fecal occult blood test (recommended by WHO) , sigmoidoscopy, colonoscopy.

69. REFERENCES Bailey & love short practice of surgery 27 th edition Schwartz’s principles of surgery 10 th edition.