Exercise Medicine & Bowel Cancer
What is Bowel Cancer ?
Also known as colorectal cancer, any cancer that affects any part of the bowel (small and large intestines, later parts of digestive system after the stomach). 15 000 Australians are diagnosed each year, including 1000 people under the age of 50.
Bowel cancer is estimated to be the 2nd largest cause of cancer deaths in all Australians, however 90% of cases can be successfully treated when detected early. Currently the average 5-year survival is 65%.
Improved surgical techniques, standardisation of preoperative and postoperative care and, importantly, the addition of adjuvant chemotherapy has improved survival rates significantly , leading to a large number of people living with the effects of bowel cancer and it’s treatment.
Along with lifestyle factors such as poor diet and excessive alcohol consumption/smoking, there are a range of familial/hereditary conditions (in addition to family history of cancer) that are known to increase bowel cancer risk (Lynch syndrome, Familial Adenomatous Polyposis/FAP and sub-types, Peutz-Jeghers syndrome etc)
Diagnosis
All Australians aged 50–74 years should ideally be offered screening every two years given the association with age and lifestyle factors, although for those with any pre-identified risk factors are recommend to undertake screening from 45 years old.
-Fecal occult blood test (FOBT) and fecal immunochemical test (FIT) are used to find blood in the feces, or stool, which can be a sign of polyps or cancer. A positive test, meaning that blood is found in the feces, can be from causes other than a colon polyp or cancer, including bleeding in the stomach or upper GI tract.
-Stool DNA tests analyse DNA from a person’s stool sample to look for cancer. It uses changes in the DNA that occur in polyps and cancers to find out if a colonoscopy should be done.
-Colonoscopy & Sigmoidoscopy allows the doctor to exam the entire colon and rectum while a patient is sedated, while also being able to remove polyps or other tissue for examination during the procedure (Biopsy)
–Biopsy involves small samples of the bowel being removed and then looked at with a microscope to identify abnormal cells and assist in grading the disease progression
- MRI imaging can be done before a biopsy to look for areas in the bowel and digestive tract that are suspicious for cancerous cells.
Grading
Colorectal cancer is often described in terms of the cancer location along the digestive tract (colon vs rectal cancer). A common grading system used in assigning a stage of (stage I- IV) all cancers is the T N M (Tumour, Lymph Node involvement, Metastasis) classification, which is described in more depth here.
Metastasis (where the cancer cells begin to spread to other tissues)
– Lymph Node Biopsy involves removing a single or multiple lymph nodes for examination and can detect if the cancer has spread to the lymphatic system. This can improve the accuracy of pTNM staging
– PET-CT/MRI & Bone Scans are additional investigations that can pick up on the cancer spreading to other areas including other organs, bones and soft tissues. This is another way staging accuracy can be improved.
Other terminology may be used clinically regarding bowel/colorectal cancer that may describe the cancer in terms of its size, extent of spread, speed of growth and capacity for treatment.
So how does exercise fit this picture?
If you’re unfamiliar with the idea of “Exercise Oncology’/Exercise Medicine based management of Cancers - check out our Intro to Exercise Oncology resource.
Exercise Medicine in Bowel Cancer Prevention
Given the huge effect of lifestyle modification on bowel cancer incidence, physical activity throughout life is a well established and powerful tool to reduce the risk of bowel cancer.
In a large study of 932 people, it was shown that those who exercised for ≥ 1 hour per week had a lower prevalence of colon polyps and adenoma than those who exercised for < 1 hour.
An area that has received attention in recent years, is the relationship between bowel cancer and lifestyle-related metabolic disease, such as Type 2 Diabetes. While both conditions may have a large dietary or lifestyle related component - there are similarities in the way exercise influences Type 2 Diabetes that are seen in the way exercise affects the growth and spread of bowel cancers.
A key discovery from this focus - is that bowel cancer is heavily influenced by Insulin (the nutrient storage and growth hormone that is dysfunctional/impaired in diabetes) as well as other similar growth factors (Insulin-like Growth Factor variants).
One of the ways this works is through a system, called the IGF-Axis which is influenced heavily by physical activity and exercise. What’s also interesting, is that insulin receptors in cells are actually key players in the growth and regulation of cancerous growth factors (in fact about half of insulin receptor function is actually not related to the standard storage of sugar/carbohydrates and fats - but rather are involved in triggering cellular cascades that elicit cancer cell mutations).
There are also a range of anti-inflammatory mediators that exercise releases and regulates over time, which have been suggested to play an important role in cancer-resistance.
Great research from University of Queensland has shown that the right type of exercise can positively affect hormone-cascade systems (the IGF-Axis, Myokines such as IL-6, IL-8 etc) favourably to reduce growth and spread of cancerous cells in the bowel.
Exercise Medicine During Bowel Cancer Treatment/Active Diagnosis
In a similar sense to what was mentioned above - insulin, IGF and associated hormones all play a key role during active treatment of bowel cancer. On top of exerting direct cancer-influencing effects on the body, dysfunction of the IGF axis has been shown to impair the response to curative treatment. Therefore, interventions (like the right type of exercise!) that can normalise IGF Axis function are capable of enhancing treatment effects, and reducing the likelihood of failed treatment responses to chemotherapy, radiation and other drug based therapy.
Bowel/Bladder issues and incontinence are common following surgery and certain other treatments for bowel cancer. Pelvic floor muscle training and exercises focusing on adequate pelvic floor/abdominal control are an effective method of managing these problems .
Poor Muscle Strength, Fitness & Body Composition may occur in response to many drug related bowel cancer treatments. On top of this, reduced activity levels can also contribute to changes in body composition, fitness and fatigue. All of these areas are well-established as target treatment areas for Exercise Physiology and physical activity interventions, with research consistently showing us positive improvements across the board.
Low Bone Mineral Density can be combated with the right type of exercise. Lifelong weight-baring activity seems to have a protective effect, although we can also improve bone density, as well as delay osteoporosis secondary to cancer treatment, by performing exercises that load the muscle, joints and bones. This can be risky if bone mineral density is already low/compromised, which is why an Exercise Physiologist with expertise in the area could be useful to have on board.
Psychological Distress in those undergoing cancer treatment is common (up to 35% of people with bowel cancer) and places those affected at greater risk of being physically inactive. Exercise programs have been shown to improve quality of life and combat the effects of bowel cancer on psychological distress and depressive symptoms, although guidance from healthcare professionals (including Exercise Physiologists) may be needed to get started and maintain motivation through difficult times.
Research has shown that total physical activity equivalent to >30 mins of moderate daily physical activity is associated with a 27% reduction in severe treatment-related toxicities in people with bowel cancer.
Even as inpatients admitted to hospital for routine post-surgical/procedural care, low-moderate exercise has been trialled and proven effective for reducing length of hospital stay and improving digestive/bowel movement in stage I - III Colorectal cancer patients. Two studies included in a great research review also showed advanced colorectal cancer patients undergoing treatment were able to benefit from both supervised and un-supervised 8-10 week exercise programs.
Exercise Medicine in Bowel Cancer Survivorship
Combating the ongoing effects of treatment as above may be continued into the survivorship journey, after the cancer has been treated and an individual is in remission. After treatment, fatigue decreases over time; however, 30% of patients may continue to have complaints for years. Although issues and symptoms are usually most prominent during the first three years, long-term effects of treatment can persist and include fatigue, sleep difficulty, fear of recurrence, anxiety, depression, negative body image, sensory neuropathy, gastrointestinal problems, urinary incontinence, and sexual dysfunction. A targeted exercise routine can address these symptoms and reduce the severity of the side effects that do persist.
In terms of battling recurrence, research has shown that being more physically active and doing more exercise in bowel cancer survivors has a profound effect on reducing the likelihood of bowel cancer returning. Total blood sugar load in bowel cancer survivors are also factors linked with recurrence of cancer, which is also something the right type of regular exercise is a well established tool in managing.
Issues with incontinence and bowel/bladder concerns are likely to be most problematic in the early stages post-treatment - although there may also be a need for continued strategies and guidance throughout survivorship on pelvic floor muscle training and activation during strenuous activities. This is an area where effective management can vastly improve quality of life, especially if there have been issues with bowel/bladder function that are negatively affecting persons day-to-day tasks. On top of targeted pelvic floor muscle physiotherapy interventions in isolation, carefully prescribed exercise with a goal of maintaining adequate pelvic floor control can offer bowel cancer survivors the confidence to perform a range of physical tasks they may have struggled with.
Exercising with a Stoma/Colostomy bag?
In some cases (less than 10%), surgery to remove the tumour requires a temporary or permanent opening created (i.e., a stoma) for the collection of body waste in a colostomy bag. Exercising with a colostomy bag can be challenging, but it is not a reason on its own to avoid exercise. Occasionally muscles of the abdominal wall can be weakened due to the surgeries related to treatment and stoma, and specific abdominal muscle exercises may be useful to assist in developing core stability without excessively increasing intra-abdominal pressure (Valsalva/Breath holding/’Over-bracing’). Nonetheless care is needed to protect this area during exercise, and it may be useful to have guidance from an Exercise Physiologist on how to safely perform these exercises or other types of physical activity.
Dosage?
Clinical guidelines suggest all cancer survivors should engage in 150-minutes of moderate-intensity or 75-minutes of vigorous-intensity aerobic exercise per week, perform 2-3 muscle strengthening sessions per week, and perform flexibility activities on days of exercise. However, there are important considerations to make when trying to achieve the best results from exercise before, during and after bowel cancer.
But research tells us only 21% to 42% of colorectal cancer survivors could safely achieve doses of exercise recommended by the American College of Sports Medicine (ACSM), American Cancer Society (ACS), or National Comprehensive Cancer Network (NCCN).
As we know, insulin plays a large role in bowel cancer prognosis - therefore exercises that are able to modulate insulin, IGF and other associated hormones/chemicals are going to exert some of the most beneficial medicinal effects. Higher intensity/vigorous exercise and muscle strengthening exercises are known to have the greatest effect on insulin and blood glucose levels in healthy individuals and diabetics, with recent discoveries finding the same is likely true for those with bowel cancer.
Research I was involved in from UQ Exercise Oncology set out to compare the effect of stationary bike based HIIT (High Intensity Interval Training) vs MICT (Moderate Intensity Continuous Exercise, the traditional ‘cardio’ type workout). What we found, is that HIIT had a significantly greater effect on improving insulin sensitivity as well as reducing blood sugar levels when compared with MICT. We also saw the the strongest effects on markers of insulin sensitivity after HIIT were seen in the bowel cancer survivors who had impaired fasting glucose/chronically elevated blood sugar levels. While this was only a short term intervention (4 weeks) - the results are promising as this can direct precise exercise-based medicine interventions to achieve the best results in those battling the effects of bowel cancer.
The same team of researchers has shown that HIIT is a safe and effective mode of exercise for rapidly improving cardiorespiratory fitness and body composition in bowel cancer survivors. There are also immediate short-term effects of HIIT on mediating a variety of cell responses that directly limit cancer growth, which suggests there are further benefits from regular or repeated bouts of this type of exercise.
We also have great evidence to show that performing strength training/resistance exercise using large muscle groups is an effective method to combat blood sugar dysfunction and insulin resistance in healthy individuals as well as those with Type 1 and 2 diabetes. By directing exercises to achieve similar outcomes, we are able to provide the body with the best environment to combat bowel cancer growth, spread and recurrence.
Furthermore, the known side-effects of many bowel cancer treatments (including surgery, chemotherapy and radiation) can have lasting, deleterious effects on a person that requires a targeted treatment plan to improve symptoms or enhance function. Losses in strength and muscle mass may be the key limiters to a fulfilling, functional lifestyle for some - whereas for others, fatigue and low aerobic fitness may be the main areas an exercise prescription needs to address.
At first - the frequency, intensity, type and duration of the exercise should be based on the level of function and medical status of the person, in addition to individual goals and preferences. This should allow for gradual progression as the body adapts and ongoing modification to exercises as needed to ensure safety and that the most effective outcomes are always being achieved.
Getting dosage right is where the expertise of an Exercise Physiologist with a speciality in oncology/cancer care can be incredibly useful.
When Not to Exercise
A high quality review of studies in 2020 found that exercise was no more dangerous than usual care (or no exercise) for those with bowel cancer in terms of potential adverse events (injuries, treatment complications etc).
Contraindications /when not to exercise for bowel cancer patients include, but are not limited to:
Acute infection/signs of infection
Acute/severe bowel and bladder problems,
Extreme fatigue, ataxia or anemia,
General cardiovascular and respiratory contraindications for an exercise regimen.
Hemoglobin level < 10.0 g/dL
Absolute Neutrophil Count (ANC) < 0.5 x 10^9/L
Platelet Count < 50,000 x 10^9/L
Precautions should be taken in the following situations - this is where guidance from an Exercise Physiologist could be the most beneficial.
Platelets > 50,000–150,000: avoid tests (high impact) or exercise (contact sports) that increase risk of bleeding
White blood cells > 3000–4000: ensure proper sterilization of all equipment
During active treatment (chemotherapy or radiation)
Acute post-operative/post-treatment phase
Although there is a lot to consider when going through the journey of bowel cancer, movement and exercise are an important part of treatment that have powerful, direct and indirect effects on a range of cancer outcomes.
The journey for everyone is different, which is why having an individualised approach to preventative medicine, rehabilitation and survivorship is so important.
If you’d like more information on any of the information above or would like a better understanding of how movement can be medicine for you, keep an eye out for more content like this or get in touch to book an appointment for a personalised plan of action today.