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Colorectal cancer (CRC) is a rapid abnormal cell growth (malignancy) that affects the large part of the large intestines (colon) and/or its end (rectum). [1]
These clusters of cells are called adenomatous polyps and develop from the tissue membrane of glandular tissue. [2]
Polyps can start as benign and non-cancerous but with time can develop and become cancerous. [3]
CRC
Death rate from colorectal cancer has been dropping for the past 30 years but still the second leading cause of cancer death in the U.S.
Overall lifetime risk of developing colorectal cancer is: 1 in 21 for men and 1 in 23 for women.
There are currently more than one million colorectal cancer survivors in the U.S[4].
Epidemiology
CRC is one of the most common cancers. In fact, it is cited as the third most common cancer globally [5] and has ascended to the second leading cause of cancer death, according to the World Health Organisation. Worldwide in 2020, over 1.9 million new cases of colorectal cancer and more than 930. 000 deaths due to colorectal cancer were reported. The burden of colorectal cancer is projected to rise to 3.2 million new cases per year (an increase of 63%) and 1.6 million deaths per year (an increase of 73%) by 2040.[6]
Approximately 20-25% of patients with CRC present with metastatic disease at the time of diagnosis and 20-25% of patients will develop metastases after treatment, resulting in a relatively high overall mortality rate of 40-45%[7]
The lifetime risk of developing CRC is 1/20 or 4.96%.[8]
The mean age of CRC diagnosis is 69 years of age. [9]
The mean mortality age of CRC is 74 years of age. [9]
Studies between 1991 and 2005 show that survival rates from CRC have increased by 30%. [10]
The risk of getting CRC increases with age and is greater in men than women. [11]
The most common area of diagnosis is the rectum and the rectosigmoid junction, with the sigmoid resulting the most favorable outcome. [12]
Etiology
Multifactorial etiology including: genetic factors; lifestyle; environmental risk factors (all have substantial effects on CRC development).
Several risk factors have been identified for CRC (low-fibre and high-fat diet, physical inactivity, unhealthy diet, diabetes, obesity, smoking, high alcohol consumption, advanced age and inflammatory bowel disease). [13]
However, more than one-half of all cases and deaths are attributable to modifiable risk factors, such as smoking, an unhealthy diet, high alcohol consumption, physical inactivity, and excess body weight, and thus potentially preventable
In recent years, the increase in CRC incidence is attributed to the increase in the elderly population, changes in dietary habits and increased risk factors such as smoking, low physical activity and obesity[14].
Lifestyle factors and obesity affect the development of various types of cancer, particularly CRC.
Colon cancer originates from rapid cell proliferation of the epithelial cells called colonocytes that line the bowel, and somatic mutations in the p53 tumor-suppressor gene. The majority of CRCs are believed to occur sporadically leaving only about 10% to 20% of CRCs to have a known hereditary component
A synergistic association is observed between physical inactivity and obesity. The International Agency for Research on Cancer (IARC) has reported that 25% of all the cancer cases worldwide are caused by obesity and sedentary lifestyle[14]
Pathology
Colorectal cancers:
98% are adenocarcinomas, arising in the vast majority of cases from pre-existing colonic adenomas (neoplastic polyps), which progressively undergo a malignant transformation as they accumulate additional mutations ie the multihit hypothesis
Metastases may be widespread in advanced disease, although the liver is by far the most common site involved.[15].
Iron deficiency anaemia (chronic occult blood loss)
However initial manifestation may be acute:
Bowel obstruction
Intussusception (a painful form of bowel blockage in which one part of the intestine slides inside another part. It can cause swelling that can lead to intestinal damage).
Heavy rectal bleeding
Occasionally metastatic disease may be the first sign.
Positive blood cultures or bacterial endocarditis with Streptococcus bovis is strongly suggestive of underlying colorectal cancer.
In general:
Right sided tumours are larger and present with a mass, distant disease or iron deficiency anaemia
Left sided tumours present earlier with altered bowel habit[15]
In many cases colorectal cancer is not discovered until it has become metastatic to other locations in the body. CRC most commonly metastasizes to the liver. It will also commonly metastasize to the lung, brain and bone, but it is uncommon to find one of these metastasis without the presence of a metastatic spread to the liver as well. [12]
Associated Co-morbidities
Approximately 51-59% of individuals with a diagnosis of CRC who are under the age of 70 do not also suffer from co-morbidities; however, in the individuals who are greater than 70 years of age, only 26-24% of them do not suffer from co-morbidities. Of this group greater than 70 years of age, the men have the highest prevalence of complicating co-morbid conditions. These conditions can have a marked impact on the treatment of the individual’s CRC diagnosis. The short-term survival is also worsened in the presence of co-morbid conditions, especially cardiovascular co-morbidities.
In addition to a physical examination, the following tests may be used to diagnose colorectal cancer.
Colonoscopy
Allows the doctor to look inside the entire rectum and colon while a patient is sedated. If colorectal cancer is found, a complete diagnosis that accurately describes the location and spread of the cancer may not be possible until the tumor is surgically removed.
Biopsy removal of a small amount of tissue for examination under a microscope).
Molecular testing of the tumor. Results of these tests can help determine your treatment options.
All colorectal cancers should be tested for problems in mismatch repair proteins, called a mismatch repair defect (dMMR).
For metastatic or recurrent colorectal cancer, a sample of tissue from the area where it spread or recurred is preferred for testing, if available.
CRC often bleeds into the large intestine or rectum, people with the disease may become anemic. A test of the number of red cells in the blood, which is part of a complete blood count (CBC), can indicate that bleeding may be occurring.
Another blood test detects the levels of a protein called carcinoembryonic antigen (CEA). High levels of CEA may indicate that a cancer has spread to other parts of the body.
Endorectal ultrasound is commonly used to find out how deeply rectal cancer has grown and can be used to help plan treatment. However, this test cannot accurately detect cancer that has spread to nearby lymph nodes or beyond the pelvis. Ultrasound can also be used to view the liver, although CT scans or MRIs (see above) are better for finding tumors in the liver.
Chest X-Ray - An x-ray of the chest can help doctors find out if the cancer has spread to the lungs.
Positron Emission Tomography (PET) or PET-CT scan.
A PET scan is usually combined with a CT scan (see above), called a PET-CT scan. A PET scan is a way to create pictures of organs and tissues inside the body.[18]
Therapeutic Management
The therapeutic management of CRC should involve a multi-modal approach, including high-quality surgery and an optimal choice of chemotherapy and radiotherapy regimens according to disease characteristics and patient preferences. Even in the case of metastatic disease, the optimal multi-modal treatments could achieve potential cure or long-term survival benefit in some patients.
The management of colorectal cancer (CRC) should be undertaken using a multi-modal approach, taking into account the extent, localization and biology of the tumor, as well as individual patient factors.
The application of targeted agents has shown much promise in the treatment of metastatic CRC. Predictive markers are important in the individualization of the optimal treatment. The future offers hope that patients will have individualized therapies based on their tumor genetics.[19]
Treatment involves local control with resection in almost all cases. Adjuvant chemotherapy is reserved for stage III disease.
Overall 5-year survival rate is 40-50%, with the stage at operation the single most important factor affecting prognosis.
Surgical Options
Polypectomy is a procedure in which polyps (small growths on the inner lining of the colon) are removed during a colonoscopy.
Local excision can be used to treat cancers in the rectum. The procedure involves removing the cancer and some tissue of the wall of the rectum. It may be done through the anus or through a small cut in the rectum. The procedure does not require major abdominal surgery.
Resection involves the removal of part, or all, of the colon along with the cancer and its attaching tissues.
Laparoscopic surgery. To perform laparoscopy, between 3 and 6 small (5-10 mm) incisions are made in the abdomen. The laparoscope and special laparoscopic instruments are inserted through these small incisions. The surgeon is then guided by the laparoscope, which transmits a picture of the intestinal organs on a video monitor.
Physiotherapy Management
Physiotherapy is traditionally used after a diagnosis of CRC to help build strength and endurance to continue to perform daily activities (ADLs). Exercise or physical activity is reported to have positive effects on the functional capacity of patients in various phases of the patient journey. [20]
A cross-sectional study in patients recently diagnosed with colorectal cancer comparing their muscle mass, core strength, and physical fragility with those of healthy subjects showed reduced muscle mass and power in the abdominal and lumbar muscles suggesting better outcomes in these patients with an early introduction (preoperative rehabilitation) of strength-enhancing programmes.[21]
A large trial conducted at 55 centres randomised 889 patients to an exercise group (445 patients) or a health-education group (444 patients) and followed these patients for approximately 8 years. The group that followed the 3-year structured exercise programme, initiated soon after adjuvant chemotherapy, demonstrated significantly longer disease-free survival and overall survival rates than those following health education. [22] This important finding suggests that therapeutic exercise - consisting of 3 phases of behavioural support and supervised physical activity - not only is capable of improving patient mobility, fatigue and sleep quality, thereby enriching the overall quality of life of CRC patients, but may also influence the level of predictive biomarkers for the outcome of CRC survivors.
Physical activity of at least 18 MET-hours per week is considered to be a rational intensity for CRC survivors to achieve a better outcome. [20]
An oncology rehabilitation therapist is usually either an occupational or physical therapist; they have an expertise when treating people with cancer. These therapists create patient-specific exercise programs. The goals of these treatment programs include:
Physiotherapy helps through all stages of treatment. Research shows better outcomes with
Preoperative supervised home-based physiotherapy intervention (respiratory, strength, and aerobic)[24].
After a CRC surgery - through the recovery process by regaining strength, mobility, and independence.eg helps maintain hip and spine ROM and strength (areas of negative impact from treatments).
In the prevention of recurrence of colon cancer through physical activity presecription eg Physical Therapists are able to provide an individualized exercise program based on this evidence with an understanding of the current treatments for cancer and how they affect a person's ability to stay active and exercise.
Physical therapists can also help offset side effects of the CRC medical treatment.
Some lymph nodes may be removed during surgery and that can interrupt the flow of lymph back to the center of the body. This treatment is used to decrease the swelling caused by this and also the pain and discomfort associated with this problem. See Manual Lymphatic Drainage (art gallery display of compression garments R)
↑Siegel RL, Miller KD, Goding Sauer A, Fedewa SA, Butterly LF, Anderson JC, Cercek A, Smith RA, Jemal A. Colorectal cancer statistics, 2020. CA: a cancer journal for clinicians. 2020 May;70(3):145-64.
↑De Marco MF, Janssen-Heijnen ML, Van Der Heijden LH, et al. Comorbidity and colorectal cancer according to subsite and stage: a population-based study. Eur J Cancer. 2000 Jan; 36(1): 95-9
