COLORECTAL CANCER

BY

DR.SEFEEN SAIF ATTYA

SOHAG TEACHING HOSPITAL

ANATOMY OF THE LARGE INTESTINE

The large intestine extends from the ileocecal valve to the anus. It is divided anatomically and functionally into the colon, rectum, and anal canal.

The wall of the colon and rectum comprise five distinct layers: mucosa, submucosa, inner circular muscle, outer longitudinal muscle, and serosa.

In the colon, the outer longitudinal muscle is separated into three teniae coli,

In the distal rectum, the inner smooth-muscle layer coalesces to form the internal anal sphincter.

Colon Landmarks

The rectosigmoid junction is found at approximately the level of the sacral promontory and is arbitrarily described as the point at which the three teniae coli coalesce to form the outer longitudinal smooth muscle layer of the rectum.

The cecum is the widest diameter portion of the colon (normally 7.5 to 8.5 cm) and has the thinnest muscular wall. As a result, the cecum is most vulnerable to perforation and least vulnerable to obstruction.

The ascending colon is usually fixed to the retroperitoneum. The hepatic flexure marks the transition to the transverse colon.

The intraperitoneal transverse colon is relatively mobile The splenic flexure marks the transition from the transverse colon to the descending colon.

The attachments between the splenic flexure and the spleen (the lienocolic ligament) can be short and dense, making mobilization of this flexure during colectomy challenging.

The descending colon is relatively fixed to the retroperitoneum.

The sigmoid colon is the narrowest part of the large intestine and is extremely mobile, This mobility explains why volvulus is most common in the sigmoid colon. The narrow caliber of the sigmoid colon makes this segment of the large intestine the most vulnerable to obstruction

RISK FACTORS

The great majority (75%) of colorectal cancers are sporadic and without identifiable risk factors other than increased age

Previous cholecystectomy and gastric surgery confer some increased risk

High risk groups include patients with : Ureterosigmoid urinary diversion Extensive colitis Colorectal adenoma Previous colorectal cancer Strong family history of colorectal cancer Familial adenomatous polyposis

CLINICAL FEATURES

80 % of Patients with colorectal cancer present electively with symptoms of several months duration

Earlier diagnosis of symptomatic colorectal cancer is therefore possible but requires greater public awareness of the nature of colorectal cancer , its presenting features and potential curability

THE CLINICAL FEATURES ARE :

Altered bowel habit Bleeding per rectum Abdominal pain Tenesmus Palpable abdominal or rectal mass Iron deficiency anaemia

ALTERED BOWEL HABIT

This is specially common in cancers of left colon or rectum

Patients may complain of recent or increasing constipation , passage of small –caliber stools or diarrhoea

Altered bowel habit may be caused by IBS or diverticular disease but colorectal cancer needs to be excluded

BLEEDING PER RECTUM

Passage of small or moderate amounts of blood mixed through the motion is suspicious for colorectal carcinoma

In rectal cancer the bleeding may be indistinguishable from that caused by haemorrhoids-which may of course ,coexisits with cancer

The likelihood of colorectal cancer is 10% in patients aged >40 years who present with recent-onset rectal bleeding

ABDOMINAL PAIN

Colorectal cancer may present with a dull ,poorly localized or suprapubic pain

Carcinoma of the right colon sometimes causes postprandial pain (provoked by the gastrocolic reflex)

Direct spread of the tumor into the adjacent structures may cause constant , well localized abdominal ,sacral or thigh pain

TENESMUS

This is an irresistable ,uncomfortable or painful urge to defaecate ,often with passage of only a small volume of stool ,blood or mucus and followed by a sense of incomplete evacuation

Tenesmus suggests rectal carcinoma ,although it may also be caused by proctitis or infective colitis

PHYSICAL FINDINGS

Physical examination is often normal ,findings may include

Abdominal fullness Hepatomegaly Rectal examination is

essential ;75% of rectal cancers are felt as a mass ,ulcer or stricture

Stool should be tested for ocult blood

Iron-deficiency anaemia

Recent onset iron-deficiency anaemia should prompt a search for a source of blood in the gastrointestinal tract particularly the colorectum

Bleeding may be intermittent , and occult blood testing may be negative

Positive faecal occult blood tests should initially be followed by colonoscopy rather than upper GI endoscopy

Iron-deficiency anaemia is more commonly due to colorectal cancer than upper GI lesion

20% of patients have distant metastases at the time of diagnosis ,such patients may present in diverse ways including

Cachexia Jaundice Ascites Pathological fractures Weight loss

DISSEMINATED COLORECTAL CANCER

DIAGNOSIS

None of the features of colorectal cancer are pathognomonic

Diagnosis is most likely to be delayed when symptoms are ascribed to benign disease such as haemorrhoids or IBS

Most usually the diagnosis will be made by a combination colonoscopy and barium enema ,these approaches are complementary

Double contrast Barium enema does not examine the anorectum adequately

Colonoscopy is more sensitive than barium enema in detecting colorectal cancer , but depends crucially on the endoscopist’s skill in visualising the entire length of the colon

Barium enema study showing stenosing (apple core) carcinoma of the colon

Barium enema. showing irregular filling defect in the caecum

Diagnosis : Cancer caecum

•Barium enema.•Irregular long stricture of the right colon. •Diagnosis : Cancer right colon.

Barium enema.

Cancer transverse colon with intussusception.

Barium enema.

Describe Irregular

filling defect & stricture with shouldering on both sides (Apple core appearance).

Diagnosis: Cancer

sigmoid.

Barium enema.

Describe Irregular

filling defect & stricture with shouldering on both sides (Apple core appearance).

Diagnosis: Cancer

sigmoid.

Barium enema. Describe Irregular filling

defect & stricture with shouldering on both sides (Apple core appearance).

Diagnosis: Cancer

rectosigmoid.

The indications to reinvestigate a patient with persistent or recurrent symptoms will depend on their nature and the doctor’s confidence in the quality and interpretation of previous investigations

MANAGEMENT

Colorectal cancer is managed by a multidisplinary team to optimise cure and outcome

Treatment of colorectal cancer may include a combination of operative resection , radiotherapy and chemotherapy as well as evolving techniques

The primary treatment for potentially curable cancer colon is segmental resection with restoration of intestinal continuity

Surgical resection is the treatment of choice for potentially curable rectal cancer

Carcinoma of the upper rectum is treated by high anterior resection generally without a stoma

Carcinoma of the mid and lower rectum is increasingly treated by low anterior resection with total mesorectal excision (TME) to minimise local recrrence rates

Leak rates are higher after this operation , so a temporary defunctioning stoma is often employed

The lowest rectal tumours are treated by abdominoperineal resection with permanent stoma where the sphincters must be removed to ensure a safe margin of clearance

Postoperative chemotherapy gives an absolute increase in five-year survival of approximately 6% in patients with involved nodes

The benefit of chemotherapy when nodes are not involved is being investigated

A small proportion of patients with rectal cancer are suitable for local resection using either a conventional transanal technique or a microsurgical technique

these procedures are usually restricted to small tumours that are judged to have a very low potential for nodal metastases

EVOLVING TECHNIQUES IN COLORECTAL CANCER

Laparoscopic resection Transanal endoscopic microsurgery Intraoperative radiotherapy Neoadjuvant chemotherapy to

downstage tumours immunotherapy

EMERGENCY PRESENTATIONS 20% Of patients with colorectal cancer

present with a complication of colorectal cancer including

-Intestinal obstruction -Perforation and peritonitis -Profuse bleeding per rectum Surgical management will be directed to

relieving the life threatening crisis and performing an adequate surgical resection of the tumour

ADVANCED DISEASE

Patients with advanced or recurrent disease are assised to determine whether this is unifocal or multifocal

Locally advanced disease without distant metastases may be amenable to wide resection perhaps including adjacent organs

Single sites of distant metastases (hepatic for example) may be amenable to radical resection

PALLIATIVE CARE

Patients with disseminated or unresectable disease cannot be cured however several interventions are available that may improve palliation

Useful palliative procedures : Resection of primary , surgical bypass or stoma

formation Stenting of colonic strictures Laser ablation of rectal tumours Radiotherapy to primary tumours / local recurrence Laser or radiofrequency ablation for hepatic

deposits Radiotherapy to painful bone deposits chemotherapy

CLINICAL FOCUS

80% of patients with colorectal cancer present electively ,often with of several month duration , the cardinal features are: altered bowel habit ; bleeding per rectum ; abdominal pain ; tenesmus; palpable abdominal or rectal mass and iron deficiency anaemia

Early stage disease , in which cancer is localised within the bowel wall , is curable in more than 80% of patients , unfortunately ,55% of patients present late with evidence of lymphatic or distant metastases

Rectal examination is essential , 75% of rectal cancers are palpable as a mass , ulcer or stricture

Patients with suspected diagnosis of colorectal cancer should undergo rapid access colonoscopy and barium enema

THANKYOU