Metastatic prostate cancer and nutrition
Is every patient with metastatic cancer at nutritional risk and what are the causes of nutritional risk?
Virtually every patient with metastatic cancer is at some level of nutritional risk. The disease is accompanied by metabolic changes, which, if left unchecked, inevitably lead to deterioration of the body and ultimately to death. These processes can be effectively stopped with specific oncological therapy, but such efficient treatment of tumors will often harm healthy tissues because some side effects of oncological therapy can worsen the nutritional state of a patient or can put them at nutritional risk. Therefore some form of nutritional support is advisable for every patient with metastatic cancer.
What is nutritional support?
Nutritional support consists of a wide array of support measures, ranging from dietary consultation to the use of certain nutritional supplements, as well as measures aiming to replace the functioning of gastrointestinal tract in order to sustain life processes. The greater the nutritional risk of a patient with metastatic cancer, the more intensive their nutritional treatment should be.
Is a patient with metastatic prostate cancer at nutritional risk?
Patients with metastatic prostate cancer are generally not regarded as at highest nutritional risk. Nevertheless, they are at some nutritional risk from their disease alone, and even more from specific treatment they are receiving.
What does it mean for a patient to have a primary or secondary form of metastatic cancer?
Patients with metastatic prostate cancer can be divided into two groups: those with primary metastatic cancer (with metastases present at the initial diagnosis of prostate cancer) and those with secondary metastatic cancer (with disease recurring after unsuccessful surgical or radiation therapy). The basic mode of treatment in both cases is hormone therapy, while chemotherapy is administered to patients from the first group as well. The purpose of hormone therapy is to lower the level of male sex hormones – therapy with the withdrawal of testosterone. The level of male sex hormones can be lowered in two ways: with hormone injections or with surgical resection of the testes. A patient's concerns can play a role in choosing one form of therapy over the other.
Why is prostate cancer treated with hormone therapy? What is hormone therapy for prostate cancer?
Because prostate cancer is a disease that responds to hormones. Cancer cells have receptors for male sex hormones. Male sex hormones (testosterone and its analogues) bind with these receptors and promote cancer cells to proliferate and metastasize.
Higher levels of male sex hormones will therefore accelerate the proliferation of cancer cells. Hormone injections or surgical castration will deny cancer cells their main source of stimulation – male sex hormones.
Hormone therapy can be administered with the use of hormone injections that prevent the release of male sex hormones from testes. The same effect can be achieved with surgical resection of the testes. Another option is orally administered pills that thwart the effects of male sex hormones.
Can hormone therapy have adverse events?
Of course. No treatment is without adverse events. When making decisions, your doctor will always consider whether the benefits of therapy outweigh the adverse events. At least in short term the adverse events of hormone therapy are reasonably manageable, therefore treatment aiming to control the disease, prolong life, and increase its quality should be given priority. The good news is that as a patient, you have great power over mitigating the adverse events. This can be achieved with a healthy lifestyle, physical activity, strength training, and proper diet.
What are the adverse events of hormone treatment?
Adverse events can manifest as increased tiredness, diminished sex drive, erectile dysfunction, hot flashes with sweating, loss of muscle mass, strength and functionality, and increased body fat. However, the benefits of treatment, i.e. prolonging life, certainly outweigh its adverse events. Managing the disease is achieved with medicines, while mitigating the adverse events is in large part under your own control.
What is the meaning of "castration-resistant prostate cancer"?
After certain time some cancer cells can develop resistance to low levels of testosterone, and the disease starts to progress again. This is what is meant by castration-resistant prostate cancer. In such cases, castration therapy must be supplemented with hormone therapy, chemotherapy, or therapy with radium isotope. Some forms of therapy require additional administration of low doses of corticosteroids (to prevent adverse effects), which can also negatively affect nutritional status.
Do patients with metastatic prostate cancer require nutritional care?
Nutritional risk should be taken into consideration for every patient. If there is such a risk, then nutritional support is appropriate. Since castration therapy can worsen nutritional status, it is advisable to screen patients for nutritional risk and comprehensive care. Male sex hormones help to preserve muscle mass, as well as strength and functionality of the body, but they are not the only stimulant of muscle growth. This can also be achieved with resistance training or anaerobic physical activity. To put it simply: we are talking about strength exercises. Such training is therapeutic in nature, not preventive.
How does physical activity fit into therapy for metastatic prostate cancer?
It has been demonstrated that patients who manage to retain lean body mass enjoy longer survival and less adverse events from specific oncological treatments. You should also bear in mind that resistance training benefits not only the muscle put under strain but other muscles as well, due to the activity of chemical messengers (called myokines).
Men in their sixties, seventies or eighties constitute the majority of patients with prostate cancer, and members of these age groups are usually also less physically active. However, at least some of these men were physically active at some point in their lives. It is best to embrace that form of physical activity you are most familiar with. Physical activity is your most potent tool for controlling the disease. Furthermore, physical exercise offers great benefits for the mind and mood, and is the only proven measure against feeling tired.
Why should cancer patients increase their intake of proteins?
Muscles are built from proteins and proteins are composed of amino acids. Amino acids are like building blocks for our muscles. In a healthy individual, old muscle tissue is continuously being replaced with the new. Due to metabolic changes in a cancer patient, this process is no longer balanced and more muscle mass is lost than is being created. Therefore cancer patients need a larger intake of proteins. The recommended daily intake for a healthy person is 1g/kg of body mass, while this number is 1.6-1.8g/kg for cancer patients. A diverse diet will easily satisfy the needs of a healthy individual. On the other hand, increased need for proteins demands a larger intake, which is why patients with metastatic cancer should consume more protein-rich food, such as meat, fish, eggs, soy, kamut, quinoa, etc. It should be stressed that protein-rich food must be consumed across the entire day (three times per day), which promotes better uptake of nutrients in the gastrointestinal tract. The uptake of proteins can be further improved by physical activity. The supply of blood to the muscles is increased during and after exercise, making the uptake of nutrients more efficient. This will maximize the process of muscle retention.
Should I lose weight as a cancer patient?
Losing weight is certainly not the objective of nutritional support. However, attention should be paid to sarcopenic obesity that concerns patients with a relatively large body mass index and an almost complete lack of functional muscle mass. Sarcopenic obesity is also a form of nutritional risk.
Should I take care not to gain deposits of fat?
The last emphasis is on the avoidance of gaining non-functional fat mass. Lower levels of testosterone will reduce basic nutritional needs (basal metabolism), which promotes generation of fat deposits given the same intake of food. Physical activity plays an important role in prevention as well, with endurance workout being the preferred choice in this case. If body mass was acceptable prior to treatment, then it is recommended to retain the intake of food while simultaneously increasing physical activity. Criteria for being overweight (body mass index) are less strict for people with disease than for healthy individuals.
What is the basic principle of nutritional support for patients with metastatic prostate cancer?
Physical activity is strongly recommended, with the emphasis on regular strength exercises. The intake of proteins three times per day is also recommended. Sufficient and regular intakes of food are necessary. Loss of appetite shouldn't result in rejection of food, which leads to undernourishment and poorer outcomes of treatment. It is important to follow the wise words of Hippocrates, the father of medicine, who said that food is medicine. So make sure your intake of food is adequate and regular despite the potential loss of appetite you may experience. Your doctor can prescribe comprehensive nutritional care if you start losing body mass excessively. Two basic evolutionary activities of human race which enabled our survival were searching for food (physical activity!) and eating. Both of them are still essential in order to live a long and comfortable life in spite of the diagnosis of metastatic prostate cancer.