Colorectal Cancer Flashcards
90% of colorectal cancer occur in patients over the age of ____?
50
Cancers in the large bowel occur in the _____ and _____?
Distal Colon and Rectum
What portion of the colon has been noted to have an increase in prevalence for women?
Right
Colorectal cancer is the ___ leading cause of cancer deaths in the US (includes both men and women).
2nd
What are the top 4 leading cancers?
Breast, Prostate, Colorectal and Lung
Colorectal Cancer has been linked to what type of diets?
Hight fat low fiber, processed and red meats, low fruits and vegs
What is Chrohn’s disease?
immune system attacks GI Tract
What are adenomatous polyps?
growths that arise in the mucosal lining of bowel
adenomatous polyps are ____?
glandular
Adenomatous polyps are villous, tubular or both?
both, based on growth pattern
What are the eight regions of the colon?
Cecum, Ascending, Hepatic Flexure, Tranverse, Splenic, Descending, Sigmoid, Rectum
What portion of the colon are intraperitoneal?
Cecum, Transverse and sigmoid
What portion of the colon are retroperitoneal?
Ascending/descending, flexures
What does intraperitoneal characteristics include?
Complete mesentery and Serosa, freely mobile
What does retroperitoneal characteristics include?
Lack of mesentery and Serosa, due to this invasion to an adjacent structure is common
What is the function of the rectal?
retain feces until the body ready to expel
What are the 3 folds of the rectum?
Superior RV, Middle RV, Inferior RV
Due to its location retroperitoneally, what structures can be invaded?
Prostate, Vagina, Bladder and Sacrum
What are the four cross-sections of the bowel?
Mucosa, Submucosa, Muscularis propria, Serosa
What is mucosa?
lining of the lumen
What is submucosa?
Rich in lymphatics and BV
What is Muscularis?
Muscle layer for peristalsis
What is Serosa?
Layer of fat
What is the lymphatic drainage of Rt & Lt colon and Sigmoid?
Rt colon drain to sup mesenteric, Lt colon and sigmoid drains to Inf Mesenteric
Where could low rectal lesions expand to?
into the anal canal and inguinal nodes
What is the clinical presentation of colorectal cancer?
Rectal bleeding, Hematochezia, Diarrhea/constipation, Stool changes
What is tenesmus?
Spasm of the rectum with desire to empty
What is the clinical presentation of left colon?
bloody stool, obstructive symptoms, abdominal pain (indicated severity)
What is the clinical presentation of right colon?
abdominal pain w/ mass, N/V, Occult blood in stool
What are testing options for the average risk person (over 45 yo)?
Annual Fecal blood test, Flex. sigmoidoscopy every 5y, Colonoscopy every 10y, CT Colonography every 5y, Stool DNA test every 3y (ONLY ONE NEEDS TO BE COMPLETED) Colonoscopy should follow any positive results
What is a proctosigmoidoscopy used for?
Procedure utilized to accurately depict size and location of lesion
What does extra-rectal mass possibly indicate?
peritoneal seeding
What is the most common malignancy of the large bowel?
Adenocarcinoma
What percentage of large bowel tumors are adenocarcinoma?
90-95%
What are the three staging systems for colorectal?
Dukes, Astler-Coller and TNM (Most common)
What percentage of colon adenocarcinomas are G1-G2?
55%
What percentage of colon adenocarcinomas are G3-G4?
30%
What is the five-year survival rate for colorectal cancer?
30%
What are the two most important prognostic factors for colorectal cancer?
Nodule involvement and depth of penetration
What is the spread pattern of colorectal cancer?
Direct extension, Lymphatics and Hematogenous
What is the most common site of mets from colorectal cancer?
Liver
What is the 2nd most common site of mets from colorectal cancer?
Lung
How is peritoneal cavity seeding possible from colorectal cancers?
tumor invades into the bowel wall and into peritoneum
What is the treatment of choice for colorectal cancer?
Surgery
What is specifically common surgery for colorectal cancer?
Rt or Lt Hemicolectomy
What cancer utilizes Lower Anterior Rectal resection?
Colon Cancer, Some rectal (NO COLOSTOMY)
What cancer utilizes abdominal peritoneal resection?
Distal rectal and anal cancer (PERMANENT COLOSTOMY)
What is the most adjuvant treatment used for rectal cancer?
Radiotherapy
Post-op XRT in conjunction with Chemotherapy is recommended. True or False?
True
What is endocavitary radiotherapy?
Sphincter preserving procedure, outpatient procedure, contact therapy machine, direct rectum delivery
When is RT given alone?
Poor surgical candidates or unresectable lesions
What does the setup of a colorectal tx include?
Prone on belly board, arms above head, markers, and possible bolus
What is the purpose of the belly board?
essentially to bring any structures up and out of the field
What is the purpose of having arms above the head during colorectal RT?
To avoid irradiating the arms during the lateral portion of arcs
What is the purpose of markers and contrast?
Contrast is able to highlight the bowel for better visualization and markers aid in planning for the correct location of tumor
What is the purpose of bolus?
The purpose of the bolus is to raise the dosage to cover a possible seeding
What are the treatment fields designed to include?
Primary tumor + 2-5 cm margins + Pelvic LN
What is the typical amount of treatment fields?
3-4
What are the typical treatment field directions used for colorectal cancers?
PA and POF laterals OR AP/PA and POF lats
What is the major organ at risk when irradiation the pelvis?
Small bowel
What is dose restriction on small bowel?
less 45 Gy
What is the dosage for a 3 field treatment? Boost/Cone down?
45 Gy, 1.8 Gy fx. 50 Gy
When are 4 field treatments utilized in colorectal tx?
When structures such as the vagina or prostate are involved
What are dose-limiting structures near the ascending and descending colon?
Kidneys, Small bowel
What is the requirement if one kidney is included in the field?
The other kidney must be shielded
What is Intra-operative Radiation Therapy (IORT)?
Field is surgically open and treatment is given to local site
What is the upside to utilizing single fx IORT vs multiple fx EBRT?
a singular high dose of IORT is equivalent to protracted doses of EBRT
What are some acute side effects of colorectal cancer?
Diarrhea, Abdominal Cramps, Leukopenia, Thrombocytopenia
What are some chronic side effects?
enteritis, adhesion and obstructions
What are some measures to prevent side effects severity?
CT w/ contrast, Full bladder, Prone, Belly board
What is some skin management during RT for colorectal cancer?
Sitz bath, Topical steriod, treatment break, loose clothing, dry and clean
