Cancer

The cancerous tumor is named based on the type of cells that are growing uncontrollably—for example, uncontrolled growth in colon cells leads to colon cancer, while uncontrolled growth in the breast leads to breast cancer (primary tumor). Cancer cells can spread to other parts of the body through the blood or lymphatic system (metastases) [1]. 

There is still uncertainty about why cancer occurs in most forms of the disease. The leading theory is that internal and external factors can increase the risk of cancer [2]:

• Internal factors: mutations (changes) that occur due to random errors in our DNA (genetic material). These errors may be inherited from our parents. Science estimates that only 5-10% of cancer cases are caused by such inherited genetic faults.

  External factors: mutations that occur when our DNA is damaged by various external factors, such as UV rays, infections, pollution, tobacco use, high alcohol intake, obesity, unhealthy diet, and physical inactivity. Science estimates that external factors contribute to the development of 70-90% of the most common forms of cancer.

However, it is important to note that not everyone exposed to these cancer-causing factors will develop cancer. But some of us are more vulnerable than others due to inherited genetic conditions. In fact, luck or misfortune also plays a role here: bad luck is associated with the development of 10-30% of the most common forms of cancer [2].

Incidence

One in three people get cancer; everyone is affected. In 2019, nearly 37,000 Norwegians received the message "you have cancer." This is more than double the number from 50 years ago, a figure that is expected to rise by 1-2% annually. Despite this growth, more people are now surviving or living longer and better with their diagnosis, thanks to more focus on prevention and better methods for diagnosing and treating cancer.

The fact that more people are recovering or living longer with their cancer means that the number of "cancer survivors" is increasing significantly. In 2021, there were more than 315,000 people in Norway who are living after or with a cancer diagnosis; over 100,000 more than 10 years ago [3].

The most common types of cancer:

In 2021, these were the most common types of cancer in Norway (number of new cases in parentheses):

1. Prostate cancer (5188)

2. Breast cancer (4023, both women and men)

3. Lung cancer (3499)

4. Colorectal cancer (3204)

5. Non-melanoma skin cancer (3097)

The four most common types of cancer accounted for 43% of all cancer cases diagnosed in 2021.

Treatment of Cancer

Fortunately, more and more people are completely recovering from cancer, and many of those who have cancer are living longer and with better quality of life than before. This is due to a combination of better methods for detecting and diagnosing cancer at an early stage, as well as more, better, and more tailored treatment methods for the various types of cancer.

Cancer treatment is divided into three main categories: surgery, radiation, and medical treatment (including chemotherapy, immunotherapy, and hormone therapy). The type of treatment a patient receives varies from person to person and from one type of cancer to another. Often, treatment involves a combination of different forms of treatment. The treatment is given either with a curative intent (aiming to cure the disease) or a palliative intent (palliative treatment aimed at slowing down the cancer, reducing symptoms, and improving the quality of life for those with cancer that cannot be cured) [1]. 

Late effects can be physical, psychological, or social in nature, and can vary in severity and impact on the individual patient [3]. Pain, hormonal disturbances, persistent fatigue (fatigue), cognitive challenges, anxiety and depression, musculoskeletal injuries, peripheral neuropathies, development of additional disorders (cardiovascular disease, type 2 diabetes, obesity, osteoporosis, new cancer disease), and difficulties participating in professional, social, and family life are examples of challenges that, unfortunately, are not uncommon in connection with cancer treatment [5].

Among other things, as many as 30-40% of cancer survivors of working age are unable to return to the workforce due to late effects of cancer treatment [6].

Talk to your primary care physician about possible measures that can help reduce your late effects.

However, it is important to note that not all cancer patients will develop late effects. Those who do develop late effects often have undergone intensive cancer treatment with radiation and/or chemotherapy, but surgical cancer treatment can also cause late effects.

The development of late effects depends on the type of cancer, where in the body the cancer was located, and the type of cancer treatment given. Factors related to the individual who has undergone cancer treatment can also be important in whether late effects develop [7].

Fatigue can occur at all stages of a cancer trajectory, and we distinguish between acute and long-term/chronic fatigue:

Acute fatigue is related to the illness or treatment. Many experience that fatigue decreases once the treatment is concluded.

Long-term/chronic fatigue is tiredness that lasts more than six months after treatment has ended and there are no longer signs of active disease. This is then defined as a late effect. Some experience fatigue symptoms only after a period of time after cancer treatment has ended and they have felt healthy for a while.

Fatigue varies from person to person. Some may experience mildly reduced energy in daily life, while others may be more or less bedridden. Many are in a condition somewhere in between. What causes one to feel fatigued also differs from person to person.

Fatigue is not necessarily visible to others, making the condition challenging to live with for those affected.

The causes of fatigue related to cancer and cancer treatment can be numerous and are often complex [9]:

Below are some examples of how people with fatigue describe their condition [8]:

• Low mood

• Difficulty concentrating

• Discomfort

• Memory lapses (especially short-term memory)

• Boredom

• Tiredness

• Exhaustion

• Weakness

• Lack of energy

• Drowsiness

• A subjective feeling that something is wrong with the body

• Physical discomfort and reduced functioning

General advice for fatigue

There is no method to cure fatigue, but there are several measures you can take to better manage and live with this condition. The following are intended as general advice, which may not be suitable for everyone. These tips are based on the results of studies, the experiences of cancer patients, and expert recommendations. It is advisable to assess what might work best for you and discuss your symptoms with your doctor, even if it may be difficult to talk about. Together, you can determine which actions are most appropriate for your situation, and especially if there are any measures you should avoid [10]:

• Try to accept that you don’t have the energy to do everything you did before.

• Plan your daily activities and prioritize those that are most important to you and bring you joy.

• Strive to live as regular a life as possible.

• Plan your day so you have time to rest.

• Take several short breaks during the day rather than fewer, longer ones.

• Rest after completing a strenuous activity.

• Set realistic goals and try to enjoy what you manage to accomplish.

• Try to identify activities that make you particularly tired/exhausted and limit them as much as possible, or spread them over a longer period of time.

• Consider what is important for you to do yourself and what you can delegate to others.

• Expect to feel tired after exertion, even if the activity itself was enjoyable.

It may be helpful to adjust daily life to a lower energy level than before the illness and to reduce the demands of everyday life—easier said than done!

Many people want to quickly return to the level of functioning they had before cancer and find it challenging that both function and energy levels remain reduced for a long time after treatment is completed.

Try to gain an overview of the activities and tasks that give and take energy. You might be surprised by how much energy it takes to do enjoyable activities, such as socializing with friends.

How can you arrange for a social life without compromising your energy? Maybe you can agree on the duration of social gatherings in advance so they don’t last too long? Or you could meet in a place with few people and little noise? Make a list to help you make better choices for yourself over time. Meanwhile, acceptance is a good foundation for living well with fatigue.

Acceptance doesn’t mean you have to like the situation, but it means accepting that this is your current reality. That way, you can start working with your body rather than against it.

What you can do yourself

Fatigue, also known as a feeling of tiredness, is a common condition during and after cancer illness.

Physical activity can be highly beneficial for those who have or have had cancer, even if you are living with a cancer that cannot be cured. Physical activity is recommended as rehabilitation both during and after cancer treatment and can provide numerous health benefits.

Not least, physical activity can contribute to a sense of mastery and control in a situation that might otherwise be dominated by illness, treatment, frequent hospital appointments, and feelings of helplessness.

From "Rest and take it easy" to "Move as much as you can"

If you had been diagnosed with cancer 30-40 years ago, you would have been advised to rest and take it easy. Fortunately, a lot has changed since then, and today we know that systematic exercise tailored to your needs is safe and offers a wide range of potential benefits before, during, and after treatment

Physical activity is a wonder drug that can, among other things [11]:

The sum of these health benefits can lead to reduced need for other health services and a quicker return to a "normal" everyday life and work, especially if you are employed. Additionally, increasing research indicates that if you manage to be regularly physically active, it may increase your chances of living longer after a cancer diagnosis (including breast, colorectal, and prostate cancer) [12].

In other words, physical activity undertaken after you have been diagnosed with cancer can increase the chances of surviving certain types of cancer—it is, therefore, never too late to get started!

To sum it up simply, we can say that a physically active lifestyle after receiving a cancer diagnosis can potentially lead to better health and quality of life, as well as fewer complications from the disease and treatment compared to being inactive.
Gå mer, sitt mindre

Be physically active as part of everyday life – walk more and sit less (World Cancer Research Fund, 2018).

The quote above summarizes the recommendations on physical activity for cancer in a clear and effective way. Behind this seemingly simple encouragement and the current recommendations on physical activity for cancer, there is a substantial amount of work from scientific reports led by the world's leading cancer researchers.

The recommendations for physical activity for cancer patients are largely the same as for the general population, which means [13]:

• Physical activity of moderate intensity (i.e., activities that make you breathe somewhat faster than at rest) for at least 150-300 minutes each week

• Or at least 75-150 minutes per week of high-intensity exercise (i.e., activities that make you breathe much faster than at rest)

• Or a combination of moderate and high-intensity activities

• Strength training at least two days a week, involving the body's major muscle groups (muscles in the legs, arms, abdomen, shoulders, and back).

Thus, a minimum of 30 minutes of physical activity daily that makes you breathe a little or much more than usual is recommended. This can include everything from housework, walking, and dancing to jogging and cycling. A combination of endurance and strength training appears to have the greatest positive effect compared to just one form of exercise alone [14]. 

Perhaps these recommendations may seem daunting in your current situation and/or if you have never exercised before. In that case, it's a good reminder that anything is better than nothing, even low-intensity activities! A leisurely walk in fresh air and daylight, some light squats, or gentle yoga exercises can feel good and are great ways to break up long periods of sitting. At the same time, it's especially important that you listen closely to your body: you may not be able to do as much now as you could before you became ill with cancer.

A key point is that physical activity should be tailored to the individual, meaning that the type of activity, the amount of activity, and the intensity of the activity should be adapted to you, your daily condition, your symptoms, your starting point, and the life situation you are currently in.

Find a good balance between activity and rest, and listen to your body!

Why is physical activity important for YOU?

Consider why it is important for you to be physically active and exercise. Often, it's easier to allocate time and space for regular exercise and physical activity in your daily life if you figure out what specifically motivates you. Could it be that you want to be fit enough to play with your children or grandchildren? Do you have a goal to complete a race, a competition, or climb a mountain peak? Or do you want to be strong enough to take care of yourself in the coming years? Is your motivation to be fit enough to go skiing during Easter? Take some time to think about why having a strong and well-functioning body is important to you!

Regardless of your starting point: the most important thing you can do right now is to limit sedentary behavior! Know that even low-intensity activities (i.e., activities where you just move a little more than being completely still) can provide health benefits if the alternative is to be inactive. Start small and gradually increase if you are a beginner or unsure of your capacity right now, and try to find activities that you enjoy doing. This increases the likelihood that you will be able to maintain physical activity continuously, rather than having to suffer through an activity that you really dislike.

Remember, it's never too late to start, and the very best form of physical activity is the activity that you actually carry out!

Recovery and Rest

During strength training or cardiovascular exercise with moderate to high intensity, the function of the muscles decreases during and after the workout, only to rebuild and become stronger after the body has had time to rest. Therefore, after you have exercised, it is crucial that your muscles have the opportunity to recover. Over time, this will lead to an improvement in the original muscle function. This process is called recovery. For instance, after a leg strength training session, you should allow these muscles to rest for 2-4 days depending on the intensity of your workout. During these rest days, you can train other muscle groups, such as the upper body, or do cardiovascular exercises.

During and after cancer treatment, the need for recovery and rest between workout sessions becomes even more crucial, as your body is or has been subjected to treatments that may diminish the muscles' ability to recover. During these periods, it is particularly important to ensure a good diet, as well as adequate sleep and rest between training sessions.

During treatment and the first 4-6 weeks after completing treatment with such types of chemotherapy, exercise of low to moderate intensity (i.e., exercise where the heart rate does not get too high) is recommended. At the first medical check-up after treatment is completed, the doctor will assess whether these restrictions should be maintained [15].

If you have any of the absolute contraindications, it is recommended that you wait with high-intensity activities and training until you have spoken with healthcare professionals. However, a walk in the fresh air at a low to moderate pace can still be beneficial for you.

If you have any of the relative contraindications, it is important that you listen closely to how your body feels and let your daily condition guide the intensity and duration, rather than rigidly following your training plan. If you pay attention to your body's signals, it is safe for you to exercise - both at high and low intensities.

In summary, physical activity at low-to-moderate intensity is safe; both with absolute and relative contraindications, and can be beneficial for you! Just remember to listen to your body during and after the activity, so you can gauge how well your body handled the activity and make any necessary adjustments for next time. It is important that you are aware of how your body feels and let it guide how hard you can train, rather than strictly following a training plan.
Fysisk aktivitet ved utmattelse/fatigue

Regular physical activity and exercise can reduce fatigue and is the most effective measure against prolonged fatigue in cancer patients [16], [17].

To prevent or reduce fatigue, people who have or have had cancer are recommended to exercise [18]:

• three weekly sessions of endurance training at least at moderate intensity, and

• strength training two to three times per week.

The training can be safely carried out at high and/or low-to-moderate intensity; the most important thing is that you find a type of exercise and intensity level that you enjoy enough to perform the activity regularly [17]!

Just remember that daily form varies for everyone, so adapt your training to your current condition. Too much or too little exercise can worsen fatigue, so it's important to find an appropriate level (frequency and intensity) that suits you where you are right now, and a good balance between activity and rest. Think long-term (months) and increase your activity gradually and cautiously over a period [16].

Physical activity with bone metastases

Generally, people with bone metastases are advised to be as physically active as possible within their pain threshold [19].

If you have bone metastases that increase the risk of fractures, it is recommended that you seek an assessment from your treating physician regarding the precautions you should follow. If you experience pain during weight-bearing activities (standing, walking), it is important to contact healthcare professionals for an individual assessment and plan for what is safe for you to do. Imaging of the skeleton and consultation with a radiologist should ideally be sought initially.

However, this does not mean you should remain sedentary: a lack of physical activity can lead to muscle loss and reduced physical function, which can further increase the risk of bone fractures and bone pain.

Generally, you should follow load guidelines from your orthopedist/oncologist; most often this involves loading to the pain threshold. Be as physically active as your conditions and pain allow. Some increase in pain under load is accepted, but the pain should not persist over time after the load has ceased, or become significantly worse. You should be especially vigilant about changes or increasing symptoms [19],[20].

Recommendations:

• Avoid loading the body parts affected by bone metastases.

• For stable disease, static strength training of the affected area is recommended to maintain function and mobility.

• Choose strength exercises for parts of the body that are not affected to maintain function.

• Train balance to prevent falls.

• Avoid activities with a high risk of falls and injuries (horse riding, water skiing, slalom skiing…).

• Choose activities with a low risk of incorrect loading and injuries, such as strength training using machines instead of free weights.

• Limit exercises that cause significant twisting in the metastasis area (certain yoga twists, golf, tennis…).

• Limit movements that cause pain, seek medical help if pain persists after activity has ended.