Deck 2

Question 1

What is the length of the colon?

Answer 1

~150cm

Question 2

What are the colon divisions?

Answer 2

Its divided into five segments defined by its vascular supply and by its extraperitoneal or retroperitoneal location: the cecum (with appendix) and ascending colon, the transverse colon, the descending colon, the sigmoid colon, and the rectum.

Question 3

What are symptoms associated with CRC? Corrolation between stage of disease?

Answer 3

Symptoms associated with CRC include:
lower GI bleeding, change in bowel habits, abdominal pain, weight loss, change in appetite, and weakness, and in particular, obstructive symptoms are alarming.

Apart from obstructive symptoms, other symptoms do not necessarily correlate with stage of disease or portend a particular diagnosis.

Question 4

What signs can be found on Physical examination?

Answer 4

Physical examination may reveal a palpable mass, bright blood per rectum (usually left-sided colon cancers or rectal cancer) or melena (right-sided colon cancers), or lesser degrees of bleeding (hemoccult-positive stool). Adenopathy, hepatomegaly, jaundice, or even pulmonary signs may be present with metastatic disease.

Question 5

Is there connection between clinical picture and location of the disease?

Answer 5

Obstruction by colon cancer is usually in the sigmoid or left colon, with resulting abdominal distention and constipation, whereas right-sided colon cancers may be more insidious in nature.

Question 6

What can be found on labratory results of suspected CRC?

Answer 6

Laboratory values may reflect iron-deficiency anemia, electrolyte derangements, and liver function abnormalities.

Question 7

What is a marker to follow after surgery?

Answer 7

The carcinoembryonic antigen (CEA) may be elevated and is most helpful to monitor postoperatively, if reduced to normal as a result of surgery.

Question 8

What should clicinal interview include? What tests are important?

Answer 8

Complete history, family history.
Physical examination, laboratory tests, colonoscopy, and pan-body computed tomography (CT) scan. For rectal cancer, additional imaging techniques, such as magnetic resonance imaging (MRI) or endoscopic ultrasound (EUS), are utilized to further characterize the primary tumor prior to therapy.

Question 9

What is the role of transabdominal US?

Answer 9

Whereas transabdominal ultrasound is not routinely used in the staging of colon cancer, recent advances in this technology as well as its value as a highly cost-effective and noninvasive means for evaluating other abdominal tumors has prompted new interest. In one of the first studies to report on the role of transabdominal ultrasound in the preoperative assessment of colon cancer, Shibasaki et al. found an overall T staging accuracy of 64%, which increased to 89% when a three-tier approach was used (Tis/ TI, T2, and T3/ 4).
Of the 98 biopsy-proven cancers, all but 2 (located at the splenic flexure) were detected by ultrasonography. Although still investigational, this technique could prove to be an important alternative or adjunct to existing staging protocols.

Question 10

what about stool based tests of diagnosing CRC?

Answer 10

Technology now exists to extract genomic DNA or protein from stool and assay for evidence of genetic alterations. Large-scale validation studies are in progress, including one that describes an automated multitarget sDNA assay (fecal immunochemical testing) with a 90% specificity and 98% sensitivity for the detection of CRC as well 83% sensitivity for advanced adenoma with high-grade dysplasia.

Question 11

What is Epi proColon?

Answer 11

Blood-based test, was shown to be noninferior to fecal immunochemical testing.

Question 12

What are the recommendations of screening in average risk patient?

Answer 12

Different Options:

1. Fecal occult blood testing - yearly.
2. Flexible sigmoidoscopy- every 5 years.
3. Colonoscopy- Offer every 10 years.

Question 13

What is defined as familial risk of CRC? What are the recommandations for this population?

Answer 13

People with a first-degree relative (parent, sibling, or child) with colon cancer or adenomatous polyp diagnosed at age younger than 60 y or two first-degree relatives diagnosed with colorectal cancer at any age.

Be advised to have screening colonoscopy starting at age 40 y or 10 y younger than the earliest diagnosis in the family, whichever comes first, and repeated every 5y.

Question 14

What are the recommandations for patient with FAP?

Answer 14

Flexible sigmoidoscopy to start at ages 10– 12 y. Genetic testing (for FAP, upper endoscopy with side-viewing scope) should be done every 1– 3 y.

Question 15

What are the recommandations for patient with HNPCC?

Answer 15

Colonoscopy every 1– 2 y starting at ages 20– 25 y or 10 y younger than the earliest case in the family, whichever comes first. Genetic testing (for HNPCC, consideration should be given to screening for uterine and ovarian cancer with hysteroscopy and transvaginal ultrasound, the frequency of which varies within centers).

Question 16

What are the recommandations for patient with Personal history of adenomatous polyps?

Answer 16

A. If one or more polyps that are malignant or large and sessile or colonoscopy is incomplete, then follow-up colonoscopy should be in the short term.
B. If three of more polyps, follow-up colonoscopy in 3 y. C. If one or two polyps (< 1 cm), follow-up colonoscopy in 5 y (or more).

Question 17

What are the recommandations for patient with Personal history of colorectal cancer?

Answer 17

A. Colonoscopy is incomplete at time of diagnosis of colorectal cancer due to obstruction, then repeat colonoscopy 6 mo after surgical resection.
B. Colonoscopy is complete at time of diagnosis of colorectal cancer, then repeat colonoscopy in 3 y, and if that is normal, then repeat every 5 y.

Question 18

what is the most sensitive method of screening? what are the advantages of this method and disadvantages?

Answer 18

Optical colonoscopy is currently the most sensitive method for screening.
Advantages include direct visualization, with the ability to remove polyps (with rate-limiting factors of size and anatomic location) and to obtain biopsies. Disadvantages involve the preparation, invasive nature of the procedure, and potential side effects that include perforation (although this is < 1%).

Question 19

what is the range Flexible sigmoidoscopy can visualize?

What must it be coupled with? disadvantages of this coupled method?

Answer 19

Flexible sigmoidoscopy allow visualization of the rectum, sigmoid colon, and descending colon to the splenic flexure.

Flexible sigmoidoscopy should not be considered as a single screening measure but requires coupling with barium enema. Barium enema allows visualization of the entire colon, and experience is necessary to ensure proper visualization of the rectum.
However, small polyps may be missed. Furthermore, if a luminal polyp or mass is identified, then colonoscopy will be necessary for polypectomy or biopsies.

Question 20

Give two meta-analysis that evaluated use of CT Colonography?

Answer 20

Two meta-analyses published in 2011 provide strong support for the implementation of CT colonography (CTC) as a viable alternative to optical colonoscopy in both average- and high-risk populations:

1. In a review of 4,086 asymptomatic patients, de Haan et al. estimate sensitivities of 82.9% and 87.9% and specificities of 91.4% and 97.6% for adenomas ≥ 6 and ≥ 10 mm, respectively.
2. complementary analysis looking exclusively at cancer detection, Pickhardt et al. 110 concludes that CTC is not only clinically equivalent to colonoscopy but perhaps even more suitable for initial investigation given consistently high sensitivity (96.1%) without heterogeneity across 49 studies and 11,151 patients, despite wide variation in technique.

Question 21

Is there a place for CT colonography in the preoperative setting?

Answer 21

CTC may also offer improvements in preoperative staging as one study found this technique to be highly predictive of T3 to 4 tumors. Whether this information will prove as clinically relevant in colon cancer as it is for the rectum remains to be seen.

Question 22

ogive other alternative for colonoscopy or CT colonography in diagnosis for CRC?

Answer 22

Another alternative to optical colonoscopy, which may be more acceptable to patients even than CTC, is the colon capsule PillCam Colon 2 (Medtronic, Minneapolis, MN), now in its second generation, and reported to have a sensitivity of almost 90% for the detection of significant lesions.
Further research is necessary to address issues of long-term benefit, cost, and efficacy in average- risk individuals.