This document provides an overview of colorectal cancer. It discusses that colon and rectal cancers are separate but share a similar path of carcinogenesis. Colon cancer is more common and preventable/curable. 90% of cases occur after age 50. Screening has reduced mortality by nearly 50% in the US. Staging determines prognosis and treatment. Common diagnostic tests include colonoscopy, biopsy, and imaging. Surgery is the primary treatment while radiation poses toxicity risks.

1. Colorectal Cancer
Mohammad Saraireh
School of Nursing
The Hashemite University
2021/2022

2. Introduction
• colon and rectal cancers may share a similar cellular path of carcinogenesis, But
they are separate diseases
• In terms of incidence, colon cancer is 2.5 times more common than rectal cancer,
and anal cancers account for fewer than 4% of all lower gastrointestinal (GI)
cancers
• Colon cancer is, in most cases, a preventable and curable disease, which is known
to be influenced by genetic as well as environmental factors such as nutrition,
exercise, smoking and obesity
• 90% of cases occurs after the age of 50
• Overall colorectal cancer mortality has decreased by 47% among men and 44% among
women from 1990 to 2015 in the United States A portion of this decrease can be attributed to
the introduction of high-quality cancer screening for colorectal
• about 39% of individuals who have colon and rectal cancers present with localized
disease with the promise of a 90% 5-year survival; the remaining 61% have regional
disease (lymph node involvement or involvement of adjacent organs) or advanced
disease at diagnosis9 Regional spread to lymph nodes or adjacent organs reduces
the 5-year survival rate to approximately 67%. If the cancer has spread to distant
sites the 5-year survival is 10% or less. (American Cancer Society. Colorectal

3. Incidence and Prevalence
• Colorectal cancer is the second leading cause of
cancer related deaths, and the third most common
cancer in the world affecting both men and women
(Global Cancer Statistics 2020)

4. Global Cancer Statistics 2020

5. Incidence and Prevalence in Jordan
• In Jordan colorectal cancer is the second most
common cancer incidence with 1260 new cases in
2020 for both sex; 10.9% of all cases (Globocan
2020)

6. Global Cancer Statistics 2020

7. Jordan Cancer Registry (JCR)
Cancer Incidence in Jordan - 2016

8. Etiology and Pathophysiology
• Colon cancer develops as the result of an accumulation of genetic mutations. With or
without familial risk (sporadic mutations more common), colon cancers seem to develop
from mutations in similar genes, although the progression of accumulated mutations may
differ
• The most commonly mutated genes in colon cancer are:
i. The adenomatous polyposis coli (APC) genes (tumor suppressor genes)
ii. K-ras oncogene
iii. p53 tumor suppressor gene
iv. Deleted-in-colon-cancer tumor suppressor gene
v. Epidermal growth factor receptor (EGFR) overexpression, which inhibits apoptosis
(programmed cell death) and leads to the formation of new blood vessels (angiogenesis)
and metastatic spread
• 15% of patients with colorectal cancer have microsatellite instability (MSI), related to errors
in DNA replication
• Colon cancers are generally known to evolve through a multistep process involving a
benign adenomatous polyp that eventually becomes cancerous. This entire process can

9. Etiology and Pathophysiology
• Colon tumors can be divide into two general classes: those with chromosomal instability
(CIN) and those with microsatellite instability (MSI). About 85% of sporadic colon cancers
have CIN and 15% have MSI. Characteristics of CIN include nonrandom chromosome
losses Microsatellite instability (MSI) characteristics are related to defects in mismatched
repair (MMR) genes
• Some colorectal caner can be classified as Inherited colon cancer like :
i. Familial adenomatous polyposis (FAP) involves a mutation in the APC tumor suppressor
gene. Normally, this gene brings about death of the colonic cells once their usefulness is
complete
ii. Hereditary nonpolyposis colorectal cancer (HNPCC) is also known as Lynch syndrome
• Colon cancers are generally known to evolve through a multistep process involving a
benign adenomatous polyp that eventually becomes cancerous. This entire process can
take approximately 10 years.

11. Prevention and Risk factors
• Certain lifestyle modifications can be correlated with reducing the risk of CRC
i. Physical Activity
ii. Diet (fruits and vegetables (Dietary fiber) Processes meat)
iii. Aspirin and NSAIDs (Selective COX-2 inhibitors)
iv. Smoking
v. Alcohol
unmodifiable risk factors :
i. Inflammatory bowel disease
ii. Familial adenomatous polyposis (FAP)
iii. Hereditary nonpolyposis colon cancer
iv. First-degree relative having colon cancer

12. CRC Screening
• Screening of average-risk individuals reduces CRC incidence by
detecting and removing pre-cancerous polyps, and CRC mortality by
detecting cancer at an early, curable stage.
• CRC screening should be performed as part of a population-based
program that includes a systematic methods
• Organized screening programs that provide direct outreach to patients
and clinic-focused interventions have been shown to increase CRC
screening rates, reduce mortality, and minimize disparities by
race/ethnicity
• Screening rates improve when programs offer different options of
screening tests to ensure that testing characteristics are aligned with
patient's preferences

13. The Screening Options
CRC Screening Modalities:
Structural Screening Tests:
• Colonoscopy
• Flexible Sigmoidoscopy
• Computed Tomographic
Colonography
Fecal-Based Screening Test
• Multitargeted stool DNAbased test
(mt-sDNA)
• High-sensitivity guaiac-based test
• Fecal immunochemical test

14. Risk Assessment
Average risk Persons with at least 45 years of age and have
no other major risk factors
Increased risk
-Persons with family by birth has a history of
colorectal cancer or advanced precancer polyps
-Persons who have had colorectal cancer or
polyps that increase cancer risk
-Persons who have either one of these
inflammatory bowel diseases:
• Ulcerative colitis
• Crohn’s colitis
High risk
-Persons who have one of these hereditary
cancer syndromes:
• Lynch syndrome
• Polyposis syndromes, such as classical and

15. Screening Guidelines
Average risk of colorectal cancer Screening starts at age 45

16. Screening Guidelines

17. Screening Guidelines

18. Screening Guidelines

19. Screening Guidelines

20. CLINICAL MANIFESTATIONS
• Clinical manifestations of tumors in the colon vary
depending on location, most common Clinical
manifestations of CRC are:
• - Progressive fatigue
• - Black tarry stools with or without mucus or bright red blood
in the stool
• - A feeling of incomplete stooling
• - Change in bowel habits, such as constipation, diarrhea, or
one alternating with the other
• - Change in size or shape of the stool, such as pencil or
ribbon-like
• - Cramping, pain, or discomfort in the stomach or abdomen

21. DIAGNOSTIC STUDIES
• A definitive biopsy confirms the diagnosis, often done via
colonoscopy, sigmoidoscopy or urgent surgical intervention
• By Histology Assessment The most common histological
type of colon cancer is adenocarcinoma
• If cells are poorly differentiated or high grade, the cancer is
more aggressive and often associated with lymphatic or
vascular invasion.
• Some distal colon cancers may include areas of squamous
cells, so the cancers are called adenosquamous carcinomas

22. DIAGNOSTIC STUDIES
• A baseline carcinoembryonic antigen (CEA) level is drawn
once a diagnosis of CRC is made
• Computerized tomography (CT) scans and/or Magnetic
resonance imaging (MRI) of the chest, abdomen, and pelvis
are performed to evaluate metastases in the lungs, liver, and
extracolonic tissue
• (PET) scans provide whole-body evaluation and highlight
active tumors within the body (not the standard diagnostic
test at this time for initial diagnosis)
• A bone scan should be done to identify bony metastases

23. DIAGNOSTIC STUDIES
• KRAS Testing
• Activating point mutations in codons 12, 13, and 61 of the KRAS proto-
oncogene are common in colorectal and non–small cell lung cancers.
Constitutively activated KRAS mutations are strongly associated with a
resistance to anti–epidermal growth factor receptor (EGFR) therapies,
such as panitumumab and cetuximab used for treating metastatic
colorectal carcinoma.
• KRAS mutation testing is recommended prior to the initiation of anti-
EGFR therapy for these malignancies
• Testing is now routinely requested in the clinical practice to provide
data to assign the most appropriate anticancer chemotherapy for each
given patient

24. DIAGNOSTIC STUDIES
• KRAS Testing

25. CLASSIFICATION AND STAGING
• The prognosis for persons with colon cancer is directly related to the stage
of the disease at the time of diagnosis.
• Stage is determined by the depth of penetration of the tumor into and
through the intestinal wall, involvement of contiguous organs, the number
of regional lymph nodes involved, and the presence or absence of distant
metastases.
• Colon cancer stage is determined by the T (tumor depth of invasion), N
(lymph node involvement), and M (metastastic spread to distant organs)
system .
• significant differences in survival based on the stratification. With the
revised staging, the 5-year survival rate for patients with stage I is 93.2%,
stage IIA is 84.7%, stage IIB is 72.2%, stage IIIA is 83.4%, IIIB is 64.1%, and
IIIC is 44.3%, and stage IV is 8.1%. (American Joint Committee on Cancer.
AJCC Cancer Staging Manual. 6th ed)

26. CLASSIFICATION AND STAGING

27. CLASSIFICATION AND STAGING

28. Treatment
THERAPEUTIC APPROACHES
• Surgery
• Surgery is the primary treatment for colon cancer. The goal of surgery is to eliminate
disease in the colon, nodal basins, and contiguous organs. The tumor location,
blood supply, and lymph node pattern in the involved region will defi ne the extent of
surgical resection.
• The procedure of choice for respectable colon cancer is a colectomy with enbloc
removal of regional lymph nodes
• Careful selection of the stoma site is an important step toward ensuring the
patient’s quality of life after surgery
• Potential Complications of Colorectal Surgery:
– Anastomotic leak
– Intra-abdominal abscess
– Bowel obstruction
– Sexual dysfunction
– Alternations in bowel elimination pattern
– Stoma dysfunction. Infection or herniation

29. Treatment Surgery
THERAPEUTIC APPROACHES

30. Treatment
RADIATION THERAPY
• Radiation poses significant toxicity potential to the cells of the gut due to the
rapid turnover of mucosal cells. However, in some studies postoperative
radiation combined with chemotherapy improves survival in patients with
bulky, locally advanced disease (T4, N0, M0; T4, N1-2, M0) or T3, N0, M0
• Radiation provides local and regional control, while systemic chemotherapy
theoretically attacks metastatic cells that have embolized
• Concurrent chemotherapy : chemotherapy increases the cells’ sensitivity to
radiation damage, called radiosensitization. Efficacy in local-regional control,
especially for patients with T4 lesions, and no lymph node or metastatic
involvement.
• Potential side effects of radiation for locoregional control include enteritis,
diarrhea (small bowel), nausea and vomiting , and flank pain (kidneys)

31. Treatment
CHEMOTHERAPY
• Adjuvant chemotherapy: the use of chemotherapy or radiation after surgery
• Adjuvant chemotherapy at the colorectal level is administered with the aim of
eradicating any micrometastatic disease that may remain after surgery, with
the consequent increase in disease-free survival and overall survival of the
patient
• Survival in patients with stage III disease (lymph node involvement) is
significantly improved with adjuvant chemotherapy
• Neoadjuvant chemotherapy refers to the use of chemotherapy to reduce a
tumor's size prior to a main treatment course (often surgery)

32. Treatment
molecular targeted therapy
• Three major molecular targeted therapies
have been approved for use in advanced
colon and rectal cancers: bevacuzimab
(avastin) , cetuximab (Erbitux) and
Panitumumab(Vectibix)
• Monoclonal antibodies

33. Treatment

34. Prognosis and survival
Stage 5-year survival rate %
stage I 93.2
stage IIA 84.7
stage IIB 72.2
stage IIIA 83.4
Stage IIIB 64.1
Stage IIIC 44.3
Stage IV 8.1
(American Joint Committee on Cancer.
AJCC Cancer Staging Manual. 6th ed

35. 5-year relative survival rates for
Colon cancer Source: ACS

36. Complications
• BOWEL OBSTRUCTION
• FISTULA
• Chemotherapy and radiation toxicities
–Irinotecan - Diarrhea
–Oxaliplatin  Peripheral neuropathy

37. Post-Treatment Surveillance for
Colon Cancer ( Follow-up)

38. RECTAL CANCER
• Similar to colon cancer, rectal polyps can be found early and removed so that rectal
cancer in most cases can be prevented, or detected early so it can be cured through
regular, routine screening. For both colon and rectal cancers, 90% of disease
occurs in individuals who are age 50 or older.
• Rectal and colon cancers appear to share similar mutations, which results first in
adenomatous polyp formation
• Rectal cancer is seen more frequently in men than in women. The mortality from
rectal cancer has decreased during the last 30 years.146 Risk factors for rectal
cancer are age (risk increases with age more than 50 years old), genetic history of
FAP, family history (first-degree relative with adenomas or invasive rectal
carcinoma), smoking history in some studies, and history of ulcerative colitis.
• Bleeding from the anus is often an early sign of rectal cancer, and leads to prompt
intervention and likelihood of cure
• Later symptoms occur when large polyps or lesions bleed or cause tenesmus or
incomplete evacuation of stool, cramping, abdominal pain, and obstructive
symptoms. These cases have a lower chance of cure.

39. RECTAL CANCER
• The rectum is divided into three sections:
• Lower rectum, 3 to 6 cm from the anal verge; extraperitoneal
• Mid rectum, 6 to 10 cm from anal verge; extraperitoneal
• Upper rectum, 10 to 15 cm above the anal verge but with the upper
limit of the rectum approximately 12 cm from the anal verge; surrounded by
peritoneum on its anterior and lateral surfaces
• The location of a rectal tumor is identified by the distance from the
lower edge of the tumor to the anal verge
• The anus is the terminal 4 to 6 cm of the gastrointestinal tract, and
the anal canal connects the rectum to the perianal skin

40. Surgery
• The surgical management of rectal cancer has 5 goals:
• 1- cure
• 2- local control
• 3- restoration of intestinal continuity
• 4 - preservation of anorectal sphincter function
• 5- preservation of the patient’s sexual and urinary function
• A coloanal anastomosis preserves the sphincter mechanism in patients with low-lying rectal tumors is preferable

41. RADIATION THERAPY
• Combined modality therapy with chemotherapy
and radiation therapy has a significant role in the
management of patients with rectal cancer
• most patients with stage II (tumor penetration
through the muscle wall) and III (positive lymph
nodes) receive surgery, radiation and
chemotherapy

42. RADIATION THERAPY
• Adjuvant chemotherapy is recommended for patients with
tumors having positive circumferential or radial margins
(CRM), defined as a tumor within 1 mm of the tumor margin.
• In combination with radiation therapy ( concurrent
chemoradiotherapy )
• For patients with metastatic rectal cancer, the NCCN
guidelines suggest that single, isolated metastases may be
resected together with the primary rectal lesion, followed by
adjuvant chemotherapy and radiotherapy to the pelvis
• For patients with unresectable metastases, several
treatment options that is effective as palliative therapy

43. ANAL CANCER
• Anal cancer is comprised of cancers of the anal canal
and anal margin (perianal skin)
• Anal cancer represents less than 4% of all
gastrointestinal cancers, but its incidence is increasing
• The anus is the terminal 4 to 6 cm of the
gastrointestinal tract, and the anal canal connects the
rectum to the perianal skin
• Most anal cancers are squamous cell carcinomas
• The most important prognostic factors in anal
canal cancer are the size of the primary tumor and the
extent of lymph node involvement

44. Risk factors
• (1) infection with human papillomavirus (HPV)
• (2) HIV infection
• (3) immunosuppression
• (4) tobacco smoking
• The risk for developing anal cancer in HIV-positive men doubles
from 15 to 30
• Clinical manifestations:
• Common signs and symptoms are change in bowel elimination
patterns, bleeding, anal discharge or itching, anal mass, tenesmus,
tenderness on palpation, pain on defecation, and rarely inguinal
lymph node swelling

45. Treatment
• Surgery
• Surgical resection alone is indicated only for small, in situ lesions
that do not involve the anal sphincter and when it is expected that
adequate surgical margins can be obtained. Unfortunately, most
anal canal cancers are not detected at this early stage.
• RadiationChemoradiation THERAPY
• Chemoradiation is the preferred treatment for anal cancers.
Approximately 80% to 90% of patients will achieve a complete
response with combination therapy
• SYMPTOM MANAGEMENT AND SUPPORTIVE CARE