Colon Polyps and CRC

MC types of colon polyps

1. Adenomatous (70%)

2. Serrated (25-30%)

What is the histological progression of adenomatous polyps?

Tubular -> Tubulovillous -> Villous

Adenomatous polyps affected gene

APC gene (Tumor supressor gene)

Serrated Polyps affected genes/mutations

1. Kras mutation

2. BRAF oncogene

3. MLH1

Adenomas and small risk of malignancy

Small, <5mm

Adenomas and high risk of malignancy

1. >1 cm

2. Have villous features/high-grade dysplasia

S/Sx of colon polyps

General asymptomatic

unexplained IDA

S/Sx of ulcerated large polyp

Hematochezia (MC) and Melena

Stool based tests for CRC

Fecal occult blood test, Fecal immunochemical tests, Fecal DNA+ FIT test

Which stool based test for CRC is the most sensitive?

Fecal DNA + FIT (Cologuard)

What is the gold standard for CRC screening?

Colonoscopy

When should you use a video capsule instead of a colonoscopy to screen for CRC/polyps?

unsuitable or unwilling colonoscopy patients

Treatment for small colon polyps (<2 cm)

Colonoscopy with polypectomy

Treatment for large colon polyps

Piecemeal surgical excision (colonoscopy in 6 months)

Surveillance

Normal colonoscopy

every 10 years

Surveillance

Less than 20 hyperplastic polyps less than 10 mm in the distal colon

every 10 years

Surveillance

1-2 adenomas less than 10 mm

every 7-10 years

Surveillance

1-2 sessile serrated polyps less than 10 mm

every 5-10 years

Surveillance

3-4 adenomas less than 10 mm

every 3-5 years

Surveillance

3-4 sessile serrated polyps less than 10 mm

every 3-5 years

Surveillance

5-10 adenomas or sessile serrated polyps less than 10 mm

every 3 years

Surveillance

1 or more adenomas or sessile serrated polyps larger than 10 mm

every 3 years

Surveillance

Adenoma containing villous features or high grade dysplasia

every 3 years

Surveillance

Sessile serrated polyp with dysplasia

every 3 years

Surveillance

More than 10 adenomas

repeat colonoscopy in 1 year

When to considered Hereditary CRC and polyposis syndrome?

Family history of CRC in more than 1 family member

Personal or familial history of CRC in someone younger than 50

Familial adenomatous polyposis classical Colonoscopy finding

hundreds to thousands of colonic adenomas

Extra colonic manifestations associated with Familial adenomatous polyposis

Duodenal adenomas, Desmoid tumors, osteomas

Extra colonic cancers associated with Familial adenomatous polyposis

Stomach, duodenum, thyroid

Autosomal dominant mutation in Familial adenomatous polyposis

APC gene mutation

Autosomal recessive mutations in Familial adenomatous polyposis

MUTYH gene

Classic history for Familial adenomatous polyposis

Colorectal polyps by mean age of 15 and CRC at age 40

Dx of Familial adenomatous polyposis

Multigene panel of hereditary cancer genes including APC and MUTYH mutations

Tx of Familial adenomatous polyposis

Total colectomy before age 20

Familial adenomatous polyposis Screening

Colonoscopy q 1-2 years

EGD q 1-3 years

Harmartomatous polyposis syndromes polyps

Harmonious combination of normal tissue and hyperplastic tissue

When should you suspect Peutz-Keghers Syndrome?

Young patient with GI cancer AND Breast/gonad tumor/mass

When should you suspect Familial Juvenile polyposis?

> 10 hamartomas in colon in a patient that is ~ 10 years old

What is the inheritance pattern for Peutz-Jeghers and Familial Juvenile polyposis?

Autosomal dominant

When should you suspect Cowden's Disease

GI cancer and thyroid mass/tumor

Lynch syndrome associated cancers

Colorectal, Stomach, pancreas, urinary tract, prostate, ovary, endometrium

When to suspect lynch syndrome?

1. Personal history of early-onset CRC

2. Family history of CRC, endometrial or other Lynch-syndrome related cancers at a young age

3 Questions screen for Lynch syndrome

1. Have you had CRC or polyps dx before age 50

2. Do you have 3 or more relatives with CRC

3. Do you have a FDR with CRC or lynch-syndrome related cancer

Probability model for Lynch syndrome

PREMM5

Genetic testing recommendation for Lynch syndrome

1. Personal or FH of CRC < 50

2. History of multiple family members with cancer

3. >5% on PREMM5

Lynch syndrome colonoscopy screening

Colonoscopy starting at age 25 or five years younger than the age of dx of the youngest family member q1-2 years

Other screening for patients with lynch syndrome

1. Women -> endometrial/ovarian screening (30-35),

2. prophylatic hysterectomy ( age 40)

2. EGD at age 30-35 q2-3 years

What is the 2nd leading cause of cancer in the US

Colorectal cancer

Incidence of CRC

Equal in men and women, however reached 4-6 years later in women

Risk factors that affected CRC screening

Age > 45

Family history of adenomatous polyps/CRC

IBD

Risk factors that do not affect screening

Smoking

Consumption of red and processed meats

Alcohol

DM

Obesity

Other risk factors for CRC

Cystic fibrosis

Previous radiation

MC place for CRC

Rectal sigmoid

2nd MC place for CRC

Ascending colon

S/sx of CRC

Many are asymptomatic for years

Unexplained IDA

Left colon CRC symptoms

Colicky abd pain, change in bowel habits (pencil thin stools), stool streaked with red blood

S/sx associated with cancer in the ascending colon

Melena

Hallmark radiographic sign for CRC

Apple core sign

MCC of apple core sign in CRC

Annular carcinoma

Where does CRC metastasize first?

Men: Prostate, Liver

Women: Liver

Cancer marker for CRC

Carcinoembryonic antigen (CEA)

LFTs that may indicate CRC

Increased Alk phos with a normal GGT

If the CEA > 5, what does that indicate?

Poorer prognosis; may be mets

How should you use CEA?

Monitor treatment

Should resolve after surgery

In what patients should you exclude CRC in?

Over 40 with

1. Change in bowel habit

2. Hematocheiza

3. Unexplained IDA

4. Occult blood in stool

First line treatment for CRC

Surgical resection

What age should you start screening for CRC?

45 and up

CRC screening

Single FDR with CRC diagnosed at age 60 or older

Begin screening at age 40; if normal, q10 years

CRC screening

Single FDR with CRC or Advanced adenoma diagnosed before age 60 OR 2 FDR with CRC

Screen 10 years younger than the age of dx of the youngest relative or 40

Colonoscopy q 5 years