Cancer

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CANCER

INTRODUCTION AND OVERVIEW

Integrative cancer care requires a comprehensive and well-coordinated team or virtual team approach. The general practitioner with an integrative philosophy is well placed to coordinate appropriate screening, prevention, case finding and treatment services for patients at all stages of their journey. The cancer journey begins with awareness of risk factors and preventive strategies, and continues through diagnosis of the type and stage of cancer, decisions about conventional treatment and adjunctive therapies.

It is estimated that up to 80% of patients with cancer seek complementary and alternative therapies, almost entirely as adjunctive treatment. A study published in the Journal of Clinical Oncology reported that 88% of 102 people with cancer who were enrolled in phase I clinical trials (research studies in people) at the Mayo Comprehensive Cancer Center had used at least one CAM therapy.1 Of those, 93% had used supplements (such as vitamins or minerals), 53% had used non-supplement forms of CAM (such as prayer/spiritual practices or chiropractic care), and almost 47% had used both.

The choice of integrative therapy depends on the type and stage of the cancer, the gender and age of the patient, their preferences and previous experience of CAM, the conventional treatment being undertaken for the particular stage of the cancer, and what you and the patient are seeking to achieve through their treatment plan.

Patients diagnosed with cancer are often in a particularly vulnerable situation and are looking for guidance, which needs to be provided with a clear description of what is known about the efficacy and safety of each treatment modality. The role of each practitioner is to guide patients to decisions about treatments that are likely to enhance longevity and quality of life, to be aware of and avoid harmful interactions, and to guide them away from treatments that are potentially harmful or have little evidence or likelihood of improving outcomes for them.

Ideally, the integrative approach to cancer management improves a patient’s sense of self-control, reduces anxiety and aims to maximise the body’s potential to heal.

CANCER AND THE ESSENCE MODEL

Cancer is a very real risk, with one person in three being affected before the age of 75. As the major cause of death in developed countries it is closing in on heart disease. Cancer is also an entirely different disease than cardiovascular disease. First, it is not one disease but many, all with differing causes and treatments. Secondly, cancers vary enormously in how aggressive or life-threatening they are. Although there tends to be dread of receiving a cancer diagnosis, many cancers are not life-threatening, and even for those that are, early diagnosis and treatment can have a significant impact upon outcome. Thirdly, because cancer includes such a wide variety of conditions, some have been extensively researched and others have not. Despite all we do know, cancer largely remains something of a mystery.

Although it has just been said that cancer is different from other diseases, the ESSENCE principles of cancer prevention and management2 (see Chapter 6 from General Practice: The Integrative Approach by Kerryn Phelps and Craig Hassed, ISBN 9780729538046) are very similar whatever the cancer type. The important thing is to understand the principles, which are largely the same whatever the cancer, and not get concerned because there might be less information on one particular type of cancer. Although most research data is drawn from the more common cancers, the same rules apply for others.

PATIENT EDUCATION

In the most general sense, cancer is a disease in which a cell changes in such a way that it:

Causes

The causes of cancer are many and varied, like the disease itself. There is an ongoing battle between cancer cells being produced within the body on a regular basis, and the body’s defences. Whatever increases the risk of cancer cells being made, or reduces the body’s defences against cancer, will increase the chances that cancerous cells will evade the body’s defences and cause a cancer that poses a risk to life. There is no one factor by itself that can be implicated; it tends to be the interplay of a range of factors such as genetics (e.g. family history), chemical exposure (e.g. smoking), lifestyle (e.g. diet and exercise), mental health (e.g. chronic stress and depression), social circumstances, environment (e.g. radiation exposure), chronic inflammation (e.g. chronic hepatitis or inflammatory bowel disease), poor immunity (e.g. AIDS) and many others. There are undoubtedly many potential risk factors that we don’t know about. Whether known or unknown, these factors affect risk. Whatever the interplay of causes, it is generally thought that one way or another, a range of genetic mutations and switches are activated, which starts the disease. It is also now understood that the body makes cancer cells on a regular basis but, through a range of defences, stops the cancerous cells before they cause any noticeable illness. This is called ‘tumour surveillance’. Things that lower our bodily defences (such as stress or an unhealthy lifestyle) or increase the number of cancer cells that the body is making (such as smoking) can push the balance in favour of the cancer cells and thus allow a cancer to slip through the safety net. A cancer will often have been growing for a number of years before it is obvious as a lump or causes symptoms that bring it to the attention of the patient or doctor.

Staging

Cancers can be largely divided into two groups: solid and blood-borne malignancies.

Cancers are generally staged according to their level of spread and how aggressive or mutated they are. The TNM system is one of the most commonly used staging systems.3 This system has been accepted by the International Union Against Cancer (UICC) and the American Joint Committee on Cancer (AJCC). Most medical facilities use the TNM system as their main method of cancer reporting.

The TNM system is based on the extent of the tumour (T), the extent of spread to the lymph nodes (N) and the presence of metastasis (M). A number is added to each letter to indicate the size or extent of the tumour and the extent of spread (Box 24.1).

BOX 24.1 TNM staging system

Source: National Cancer Institute 20043

Primary tumour (T)
TX Primary tumour cannot be evaluated
T0 No evidence of primary tumour
Tis Carcinoma in situ (early cancer that has not spread to neighbouring tissue)
T1, T2, T3, T4 Size and/or extent of the primary tumour
Regional lymph nodes (N)
NX Regional lymph nodes cannot be evaluated
N0 No regional lymph node involvement (no cancer found in the lymph nodes)
N1, N2, N3 Involvement of regional lymph nodes (number and/or extent of spread)
Distant metastasis (M)
MX Distant metastasis cannot be evaluated
M0 No distant metastasis (cancer has not spread to other parts of the body)
M1 Distant metastasis (cancer has spread to distant parts of the body)

Cancers of the brain and spinal cord are not given a TNM designation but rather are classified according to their cell type and grade. Different staging systems are also used for haematological cancers and lymphomas.

Staging is important because the treatment and prognosis will vary accordingly. Obviously, if a cancer is treated in the early stages, the outcome will tend to be far more optimistic.

Hence, it is not just the primary prevention of cancer through healthy lifestyle that is important, but also secondary prevention through early detection and screening. There are many forms of screening for particular cancers, such as breast self-examination and mammography for breast cancer, faecal occult blood or colonoscopy for bowel cancer, digital rectal examination and prostate-specific antigen (PSA) for prostate cancer and chest X-ray for lung cancer. Cancers picked up on routine screening are more likely to be in an earlier stage of growth and of a lower level of malignancy than cancers detected because they have produced symptoms.

Treatment

The most widely used conventional cancer treatments tend to fall into three categories, sometimes unflatteringly referred to as:

Other forms of therapy are being developed, such as hormonal treatments, adjuvant therapy, vaccines and immunotherapy. Some promising treatments derived from plant-based products are also being researched. Some therapies are aimed at prolonging survival and others are aimed at palliation of symptoms, whether caused by the disease itself or by the treatments being administered.

Many complementary therapies have also been found to be useful for symptom control and improving quality of life. Cancer treatment can have a major impact on quality of life—for the better when it kills the tumour, and for the worse when it attacks the rest of the body, causing side effects. It is beyond the scope of this book to describe all the potential cancer therapies in detail. Suffice it to say that it is important to have full and open conversations with the team members who are helping to manage the cancer. Such a team could include oncologists, surgeons, general practitioners, counsellors, social workers, nursing, allied healthcare and complementary medicine practitioners. Other important sources of information include the community cancer agencies and support groups, medical databases such as PubMed and other respectable websites.

It is important that patients are given the opportunity to ask questions and to have them answered to their satisfaction. If they do not find the answers and resources they need, then it is important to offer them a second opinion. It is also vital that patients feel as empowered and involved as they wish to be in decisions about their cancer management. The therapeutic team plays an important role in helping patients make responsible decisions regarding their cancer care. A poor decision could be to decline a clearly beneficial conventional treatment, or to undertake a line of therapy with considerable side effects and little prospect of cure. A problem arises from the fact that cancer patients and their families are often vulnerable and can be taken advantage of through unrealistic expectations in relation to exotic and sometimes harmful or very expensive treatments that have no reasonable prospect of benefit. There are examples of both complementary and conventional treatments in this category.

This having been said, if a patient feels obstructed, undermined or disempowered in their cancer management, if they are told there is nothing they can do for themselves, if they are told that lifestyle doesn’t matter or that there is nothing outside the medical model that can help them, then they need to think seriously about finding another practitioner. Quality information and respectful and open lines of communication are much needed for both practitioner and patient, so that neither is making uninformed decisions and so that outcomes can be optimised. The Australian Senate Inquiry into the management of cancer made a number of findings and clearly indicated that the ‘cancer establishment’ should be doing a far better job in this regard.4

MIND–BODY THERAPIES

There has been much debate over the years, some of it heated, about the role of psychosocial factors in cancer. There is little debate that better mental and social health is associated with better coping and quality of life for cancer patients, but their role in the causation and progression of cancer remains controversial in conventional cancer circles. Many studies have suggested a link between psychosocial factors and cancer causes, but others have not. Some studies have looked at outcomes and others at the possible mechanisms whereby patients’ mental and emotional health changes outcomes. Because there are so many factors potentially affecting cancer, doubt often exists as to how much of a contribution psychological factors make.

In an authoritative review, Professor David Spiegel concluded that chronic and severe depression is probably associated with an increased risk of cancer, but that there is ‘stronger evidence that depression predicts cancer progression and mortality’.5a Of all the emotional factors, depression is probably the most important.6 Further, providing psychosocial support, through a support group for example, ‘reduces depression, anxiety, and pain, and may increase survival time with cancer’.5a The longer the depression has existed, say for longer than 6 years, the greater the risk factor it is. The risk is nearly doubled, independent of other lifestyle variables, and is not related to any particular cancer.7,8 The most recent review of the effect of depression on survival for patients who already have cancer concluded that clinical depression played a causal role in cancer mortality and was associated with a 39% increased mortality rate.9

Poor coping, distress and depression have been linked to poor survival for various cancers, including cancer of liver and bile duct (hepatobiliary),10 lung cancer,11 breast cancer12, malignant melanoma13 and bowel cancer. Some studies have not confirmed a link.14 Having a good global quality of life is associated with better survival for a variety of cancers.1518 Other factors, including the perceived aim of treatment, minimisation, quality of life and anger, all influence survival.19 Minimisation refers to a person minimising the importance or impact of the cancer. It is not denial, but reflects an ability to adapt or to see the illness in a larger perspective.

If psychological and social factors do play a role in the cause and prognosis of cancer, the important question is whether psychosocial interventions such as group support, relaxation and meditation and CBT produce better survival chances. That they can improve quality of life for cancer patients is clear, but unfortunately there are very few completed controlled trials examining the survival outcomes of such interventions. A number of studies have shown a significant improvement in both quality of life and survival time, but others have not.20

The most noted and first study of its type was done by David Spiegel, who studied women with metastatic breast cancer. His results showed a doubling of average survival time from 18.9 months to 36.6 months for the women who received the support program, compared with those who didn’t. The intervention included group support focused on improving emotional expression, some simple relaxation and self-hypnosis techniques, plus the usual medical management.21 Ten years after the study, three women in the intervention group were still alive but none in the group that had had the usual medical management alone were.

Another well-performed study by Fawzy and colleagues looked at outcomes for 68 patients with early-stage malignant melanoma.22 The patients were divided into two groups and followed for 6 years, at which time those who had had the usual surgical care and monitoring plus stress management showed a halving of the recurrence rate (7/34 vs 13/34) and much lower death rate (3/34 vs 10/34) than the group who had had the usual surgical management and monitoring alone. The intervention on this occasion was only 6 weeks of stress management. In this study, immune function was also followed. Originally the two groups were comparable but the stress management group had significantly better immune function 6 months into the study. We know that melanoma is one of the cancers that is aggressively attacked by natural killer (NK) cells and this probably contributed to the major difference in survival rates—that is, the immune system, monitoring for any cancer spread, was able to deal with it before the cancer had a chance to grow. Ten-year follow-up on the Fawzy program still shows a positive survival effect, although this has weakened a little over time,23 so it may be that people lose motivation over time, and ‘boosters’ may be required to maintain the therapeutic effect.

Other studies have also yielded promising results in terms of survival, for cancer of the liver,24 gastrointestinal tract25 and lymphoma.26 A number of trials have shown equivocal or negative results from a psychosocial support program, in terms of improved survival.2731 One of these trials was an attempt to replicate the Spiegel study but the results showed that, despite some improvements in mental health and quality of life, there was no significant effect on survival. An even more recent study of group support for breast cancer survival showed that the intervention did not statistically significantly prolong survival, although the average survival time in the support group was 24.0 months, compared with 18.3 months in the control group. The support program did, however, help to treat and prevented new depressive disorders, reduced hopeless-helplessness and trauma symptoms, and improved social functioning.32 Another recent study on psychotherapeutic support for gastrointestinal malignancies like stomach and bowel cancer showed a clinically and statistically significant survival benefit. This hospital-based psychosocial support program was delivered to individuals rather than in a group format. Over twice the number of gastrointestinal cancer patients were alive at 10 years if they had a psychotherapeutic intervention.33 The work by the Ornish group on support programs and cancer is probably the best researched and has shown excellent results, but this included a range of other lifestyle factors apart from psychosocial support.

Therefore, in summary, of the six trials not showing longer survival, three have shown a positive effect on mental health and the other three have not. Of the trials that showed a positive effect on survival, all showed improved mental health as a result of the intervention. So the trend seems to be that where the psychosocial intervention has marginal or no long-term benefit on mood or quality of life, it tends not to translate into longer survival. If the support program produces a significant and enduring improvement in mental health and quality of life, then it tends to have a ‘side effect’ of improving survival. Nine out of 12 studies have followed this rule so far.

Support programs vary enormously in content, duration and delivery, thus many questions in the area of psychosocial support and cancer survival will need to be answered in future research.34 For example: What kinds of programs work best? Who should they be run by? How long is the optimal duration for such a program? What are the essential ingredients? What advice should a doctor give to a patient regarding whether or not to attend a support group? To what extent does compliance affect the outcome? Does having a residential component improve outcomes?

It is likely that it is not just being in a program that is protective but also the level to which a person participates in it and lives by it. This was demonstrated by one of the studies referred to above, showing that high involvement in the program was associated with better survival, and that there was no benefit from just ‘going through the motions’.35 One paper suggested that programs of 12 weeks or longer duration were more likely to be effective.36 Those that use validated forms of meditation and also foster positive emotional responses including humour and hope are more likely to be successful. Although programs attempting to deal with psychological factors need to take into account the fact that personality traits and coping styles can affect quality of survival, there are mixed results from research on whether things such as ‘helplessness’,37,38 ‘fighting spirit’ and ‘optimism’39 affect survival. Despite the fact that a number of studies suggest that they do, other studies throw this into doubt.40

If improving mental health does indeed have survival benefits, the potential mechanisms explaining that longer survival are worth considering.41 Below is a summary of key points, followed by a more extensive discussion of each.

Direct physiological and metabolic effects

Effects of ‘anti-cancer’ hormones such as melatonin—melatonin has a number of beneficial effects on genes and immunity that have important implications for cancer.48 Poor mental health is associated with low levels of melatonin, whereas healthy lifestyle and stress reduction increase melatonin. Melatonin supplements have been associated with 34% lower recurrence rates and better cancer survival,49,50 although if taking it as a supplement it is important not to take excess doses and to monitor for side effects. The most commonly used dosages administered in these cancer trials was 20 mg taken orally in the evening.
Metabolic syndrome—metabolic syndrome has been linked as a risk factor with a range of cancers52,53; and poor mental health is associated with high allostatic load and an increased risk of metabolic syndrome. The relationship goes a significant way to explaining why a range of healthy lifestyle changes have such positive effects on cancer outcome.
Oxidative damage—stress is pro-oxidative and this has been linked to cancer risk and progression. Other markers of DNA repair are commonly suppressed in cancer patients and are potential markers of cancer susceptibility.54 Thus oxidative stress due to psychological stress coupled with a low intake of dietary antioxidants may be crucial factors in the evolution and progression of cancer. There is even evidence from animal studies that oxidative DNA damage can be classically conditioned.55 The implications of all these findings are significant but as yet barely explored. Reducing stress and having an adequate dietary intake of antioxidants are therefore important.

Indirect effects

The original belief in psycho-oncology circles was that immune cells were the main explanation for why the mind has effects on cancer outcomes, but there is much more to it than that. Immunity may explain some of the beneficial effects of stress management for some tumours, but not all. In some cancers, such as malignant melanoma or those where viral infections are an important cause, the immune system may be the main defence, but it is probably less important for cancers that are primarily caused by chemical injury, such as lung cancer. Many cancers do not wear their mutated antigens on their surface and therefore the immune system cannot recognise and attack them.56

Some hormones can also suppress cancer growth and even induce cancer cell apoptosis. The ability to change the activity of such chemical mediators may in part explain why various activities prolong a healthy lifespan in humans, such as cognitive behaviour therapy, meditation-based therapies, stress reduction, anti-inflammatory techniques, dietary (calorie) restriction and aerobic exercise. These all affect molecular mediators including dehydroepiandrosterone (DHEA), interleukins and especially melatonin.57

Chronic inflammation is not a good combination with cancer. Even the inflammation associated with major surgery has been shown to increase the growth of tumour metastases at distant sites via these hormones,58 so it is important for patients with disseminated cancer only to have surgery if it is really necessary. Reducing stress hormones59 and inducing hormones associated with wellbeing and relaxation, such as melatonin, may be part of the reason that stress reduction and psychosocial interventions help cancer survival.60

Some immune mediators (e.g. TNF-alpha) can kill tumour cells and have anti-tumour effects. We now know that many tumours are ‘dormant’ through a balance between cell division, cell death and the body’s defences.61 Upsetting this balance may explain why the occurrence and recurrence of cancer often follow recent traumatic events that were not well dealt with.62 In such a case it may be more accurate to say that emotional disturbance is a contributing or precipitating factor accelerating the cancer’s growth, rather than it being the cause of the cancer.

Apart from having significant effects on immunity63 and ageing,64 melatonin also has anti-tumour effects. It slows cancer cell replication, helps to switch off cancer genes, and inhibits the release and activity of cancer growth factors, promotes better sleep and helps to enhance the immune response.65,66 Because of the biological activity of melatonin, this has a number of implications for cancer therapy.67,68 Helping the body to stimulate its own melatonin production has many beneficial effects. Among the things which stimulate melatonin endogenously are many of the interventions that are part of holistic cancer support programs (Box 24.2).

Melatonin regulates our body clock, and therefore sleep is intimately linked with melatonin levels and thereby with cancer progression.75 This may partly explain why things that affect melatonin (e.g. doing shift work or working in the airline industry) may also be risk factors for cancer.76 Body-clock alterations commonly occur in cancer patients, with greater disruption seen in more advanced cases. Emotional and social factors as well as many symptoms associated with cancer can have a significantly negative effect on sleep rhythms. From a therapeutic perspective, using behavioural interventions to enhance sleep is a vital part of coping with cancer but it also helps to improve cancer defences and prognosis. The chapter on sleep strategies (see Chapter 43) would be useful to read if sleep is a problem.

Psychological states affect genetics. We can have a genetic disposition to cancer but, equally, DNA has protective genes such as ‘cancer suppressor genes’. It has been shown that stress impairs repair of genetic mutations77 and causes oxidative damage to DNA. In experiments on workers, perceived workload, perceived stress and the ‘impossibility of alleviating stress’ were all associated with high levels of DNA damage.78,79 Personality factors were also linked to oxidative DNA damage, with high ‘tension-anxiety’, particularly for males, or ‘depression-rejection’, particularly for females, correlating with the level of DNA damage.80 A low level of closeness to parents during childhood, or bereavement in the previous 3 years, were also associated with greater DNA damage. Psychological stress reduces the ability of immune cells to initiate genetically programmed cancer cell suicide.81

Angiogenesis, which is the process of new blood vessel formation, is vital for tissue repair but also for the growth of tumours. Solid tumours can only grow into other tissues because they are able to lay down new blood vessels. Blood vessel growth is also mediated via various cytokines. One particularly important one is vascular endothelial growth factor (VEGF), and in cancer patients high levels of this cytokine are associated with poor prognosis. Sympathetic nervous system activation, a vital part of the stress response, increases the level of VEGF, and cancer patients who report higher levels of social wellbeing have lower levels of VEGF, a good prognostic sign. ‘Helplessness’ and ‘worthlessness’ are also associated with higher levels of VEGF.82 Other studies emphasising the importance of angiogenesis in tumour progression have found links with depression.83 Tumours in stressed animals showed markedly increased vascularisation (angiogenesis) and increased levels of the hormones that produce these effects.84

As ever, we are more interested in the therapeutic potential of strategies for improving psychological wellbeing. Support groups have already been discussed but other research with bearing on this topic is also of interest. A study has been performed on the effects of mindfulness-based stress reduction (MBSR) on quality of life, stress, mood, hormonal and immune function in early-stage breast and prostate cancer patients.85 The 8-week MBSR program included relaxation, meditation, gentle yoga and daily home practice, and followed patients for 12 months. The participants showed and maintained significant improvements in symptoms of stress, their cortisol levels decreased (a good prognostic sign) and physiological markers of stress reduced, as did pro-inflammatory cytokines: ‘MBSR program participation was associated with enhanced quality of life and decreased stress symptoms, altered cortisol and immune patterns consistent with less stress and mood disturbance, and decreased blood pressure’.85a

Much more work needs to be done, but the signs are looking increasingly positive and are confirming what many patients intuitively sense and have found in their own experience—that taking an active role in enhancing mental health has positive effects on coping and quality of life, and also on outcomes.

SPIRITUALITY

Cancer, more than most illnesses, raises the prospect of one’s own mortality. As such it is a common catalyst for looking at one’s life and reconsidering what is important. Cancer can therefore be a powerful stimulus for personal growth, but for many it will lead to an emotional implosion unless motivation is positive and adequate support is given. Much has already been said in the chapter on spirituality (Chapter 12) about how having an active search for meaning or a spiritual dimension in one’s life:

These are all reasons in themselves to consider ‘spirituality’, however one relates to it, as an important part of the management of cancer. Indeed, it has already been mentioned in the chapter on spirituality (Chapter 12) that approximately 80% of patients dealing with major illness wished to discuss spiritual issues with their doctor. Among cancer survivors, the relationship between social functioning and distress was significantly affected by having a sense of meaning in life, whereas the relationship between physical functioning and distress was partially mediated by meaning.86 There have been precious few studies on whether spirituality or religion is protective against cancer. The only well-performed trial found a significantly lower incidence of bowel cancer among those with a religious dimension to their lives, and this could not be explained by other risk factors.87 This study also found longer survival in those with bowel cancer.

A related issue is whether various forms of ‘distant healing’ can assist in healing or in symptom control. A review showed that there was some evidence, albeit a little sparse and inconsistent, to suggest that forms of healing including therapeutic touch, faith healing and reiki may be helpful.88 Most of the results demonstrated so far, however, are reduction in pain and anxiety, and improvement in function. Grander claims, such as effects on tumour regression through prayer, therapeutic touch and faith healing, are mainly anecdotal and have not been rigorously investigated or proved.

CONNECTEDNESS

Connectedness can be important for different reasons at different times throughout the progression of cancer. There is the initial adjustment to a cancer diagnosis and what it potentially entails. There is the support needed in coping with cancer treatment. There is the support required in the time after treatment as one returns to work and family life, and thereafter lives with the diagnosis of being a ‘cancer patient’. It is often a lonely place to be, as many people will avoid contact with a friend or family member with cancer because they may find it confronting or not know how to deal with the potentially emotionally sensitive situation. A person with cancer may crave solitude or, conversely, feel isolated. We will not know unless we ask. Finally, if the cancer becomes advanced then there is the important phase of palliative care and dealing with the prospect of death. Support will significantly affect how this is dealt with. There is potentially no more lonely time in a person’s life and yet, with care and encouragement, it can be the most uplifting and inspiring. Ultimately, death is not optional for any of us, but how we confront death is. For those caring for a dying loved one it is important to help the loved one find their way and not to project our assumptions and fears onto them.

As has been discussed, social isolation predisposes a person to a whole range of illnesses including cancer and is associated with a higher mortality rate.89 Population studies of adults demonstrated that socially isolated males were 2 to 3 times more likely to die over the following 9 to 12 years and that socially isolated women were 1.5 times as likely to die.90 This is not explained by other lifestyle factors, although our social context has a significant influence on our lifestyle. This influence can be positive or negative. Having support to give up smoking, for example, makes it much easier, whereas a lack of support can make it all but impossible.

The most common sources of social support are family and friends. It has been shown that cancer patients who are married or have a stable relationship survive for longer than would otherwise be expected. Reviews of the studies have shown an ‘association between at least one psychosocial variable and disease outcome. Parameters associated with better breast cancer prognosis are social support, marriage, and minimising and denial, while depression and constraint of emotions are associated with decreased breast cancer survival’.91

In cancer management, social support can be provided or enhanced in a number of ways. These include the informal support provided by helpful and nurturing health-carers and the formal provision of cancer support programs. The effects of such programs have been discussed above and providing them should be part of standard cancer care.

EXERCISE THERAPY

Evidence for the role of exercise in the prevention and management of cancer is significant and growing. Regular moderate exercise helps to prevent a range of cancers, including cancers of the bowel, prostate and breast, and prolongs survival for those who already have cancer.

Reviewing the vast body of evidence, the World Cancer Research Fund has declared that physical inactivity is clearly a risk factor for cancer.92 This can be illustrated by examining some of the studies reviewed.

Over 30 studies have shown a protective relationship between physical activity and colon cancer mortality.93,94 This protective effect also extends to precancerous bowel polyps. The reduction of bowel cancer risk is around 50%.

Large-scale Norwegian studies show a 37% reduction in the risk of breast cancer in all women who exercise regularly, particularly in those less than 45 years of age, for whom the risk was 62% lower. In those who were lean, exercised approximately 4 hours per week and were premenopausal, the risk was reduced by 72%.95 Similar findings have been found for lung cancer.95 This is confirmed in an analysis of the Nurses’ Health Study.96 In postmenopausal women, brisk walking has been shown to reduce breast cancer risk. Another study looked at 75,000 postmenopausal women aged between 50 and 79 years, and showed that those who exercised at a level equivalent to brisk walking for 1¼ to 2½ hours per week had a significant breast cancer risk reduction of 18%.97 This increased to 22% in those who exercised up to 10 hours per week. A past history of strenuous exercise at age 35 or 50 was associated with a breast cancer risk reduction. Independent of smoking and nutritional status, the Norwegian study mentioned above also showed a reduced risk of lung cancer in those who exercised. Aerobic exercise seems to be the best protection against cancer, and the suggested reasons as to why exercise protects against cancer include:

Even more interesting are studies of the effect of exercise after a cancer diagnosis. The following studies illustrate this.

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