Colorectal Cancer Flashcards
What BV supplies the first 2/3 of Colon?
Superior Mesenteric artery
What BV supplies the last 1/3 of colon?
Inferior Mesenteric Arteral
What are the 4 layers of the colon wall?
Mucosa
Submucosa
Muscularis Propria
Serosa
What is the most lethal cancer?
Lung Cancer
How common is colorectal cancer?
3rd most common cancer.
Most common cancer?
Prostate/Breast
2nd most common cancer?
Lung cancer
What are the 4 Genetic Palyers in colon cancer?
APC tumor suppressor
K-RAS proto onco-gene
DCC tumor suppressor
p53 tumor suppressor
What are the steps of the Carcinoma sequence?
Mucosa ==> Adenoma ==> in situ ==> Invasive Cancer
What is the mutation inherent in FAP?
APC gene mutation on chromosome 5q
What is the inheritance pattern of FAP?
Autosomal Dominant
What is the treatment for FAP?
Total Colectomy
What is the genetic defect in Hereditary Nonpolyposis colon cancer? (lynch syndrome)
Mismatch repair gene
Hundreds of polyps, accellerated progression
Treatment for HNCC/Lynch syndrome.
Colectomy
HNCC is also associated with…………………… cancer.
Endometrial and ovarian cancers.
What are the symptoms of polyps?
Asymptomatic. May have positive Fecal Occult Blood Test when advanced.
What is required to prepare for a colonoscopy?
Clean out colon
What is difference between Flexible sigmoidoscopy and colonoscopy.
FS only goes to splenic flexure.
What are rhe benefits of doing stool based studies?
Stool Guiac and Fecal immunochemical test can diagnose while being less invasive.
What are the screening regimens for Colorectal cancer?
Colonoscopy every 10 years or Flex Sigmoidoscopy every 5 years High sensitivity FOBT every 3 years or High sense FOBT every year.
What are the screening reccomendations for colorectal cancer?
Avg risk? asymptomatic, no family history of cancer, no personal risk of polyps or cancer
start at 50yo
Repeat every 10 years
repeat sooner is polyps found
What are the screening reccomendations for colorectal cancer with a Hx of Cancer?
start earlier, repeat more frequently
What are the screening reccomendations for colorectal cancer with a Hx IBS(UC or CD)?
Colonoscopy 8-10 years after onset, 4 random biopsies every 10 years. repeat Every 1-2 years.
What are the screening reccomendations for colorectal cancer with a Hx of Lynch syndrome?
Colonoscopy 20-25yo
repeat 1-2 years
endometrial surveilance annually.
Urinalysis annually
What are the screening reccomendations for colorectal cancer with a Hx of APC/FAP mutation?
Colonoscopy age 10-12 repeat 1-2 years
colectomy once polyps are seen.
Ileorectal/ileo-anal
every 1-2 years
Diagnostic tests for Colorectal cancer?
XR Abdomen, CTbdomen/Pelvis Colonoscopy -biopsy and tattoo Proctoscopy -biopsy and measure distance from sphincters CBC/CMP CEA-serum tumor marker CT Chest/abdomen/pelvis Biopsy of Metastatic lesions US or MRI for rectal cancer
Tumor Staging of Colorectal Cancer
Tis-intraepithelial T1- MM into SM T2- invades MP T3- invades PCR tissues T4a Penetrates peritoneum T4b invades adjacent organs.
General staging of Colorectal cancer
TNM=
Tumor- invasion Depth of primary tumor
Node Extent of Regional LN
Mets- Presence of Distant Mets
Nodal staging of CRC
N0 no regional node mets
N1- Mets in 1-3 regional nodes
N2- Mets in 4+ regional noedes
15 nodes need to be examined
Mets Staging of CRC
MO- no distant mets
M1- Distant Mets
Definition of Colectomy
Resected colon with associated mesentery
Low anterior Resection Definition
Rectosigmoid resection ext below peritoneal reflection w/ associated mesorectum
Abdominal Perineal Resection definition
Anal Sphincters, anal opening, and associated mesorectum.
How to decide what Treatment to use for colon cancer?
T1, T2, T3 = Surgical resection
T3, T4 = Resections with chemo
N1, N2 = resection with chemo
Liver or lung mets = Resection with Chemo
Mets disease = Chemo
-bleeding, obstruction or perforation = Palliative resection
How to decide what Treatment to use for colon cancer?
tis, T1 = Transanal excision
T2 Resection
T3, T4, N+ = Neoadjuvant Chemo and Resection
What are the ongoing Sureillance guidelines after Tx of Colorectal Cancer?
H &P every 3-6mon x 5y
CEA every 3-6mon x 5y
CT C/A/P annually x5 y