- Physical exercise has been linked to delayed progression and improved survival rates in prostate cancer patients.
- Previous research has shown that blood from patients with advanced prostate cancer who followed an intensive training program for a few months was able to suppress the growth of cultured tumour cells.
- The authors of the same study have now shown that serum taken from trained prostate cancer patients immediately after a single high-intensity interval (HIIT) aerobic exercise session (HIIT) showed an improved ability to suppress tumor cell growth than before exercise.
- These results suggest that regular exercise could help suppress tumor cell proliferation in patients with advanced prostate cancer, and any additional exercise could potentially further increase this tumor-suppressive effect.
Skeletal muscle fibers release proteins called myokines into the blood during physical activity. Preclinical studies suggest that these myokines may suppress tumour cell growth.
Previous research has shown that serum from patients with advanced prostate cancer who completed a supervised high-intensity exercise program (HIIT) for 6 months had elevated myokine levels and a better ability to suppress tumor cell growth.
In a follow-up study published in Prostate Cancer and Prostate Diseases, the same researchers have now shown that serum samples taken from trained patients with advanced prostate cancer immediately after a single physical effort also had increased myokine levels and a greater tumor-suppressive effect than before exercise.
In other words, a single training session further enhanced the pre-existing anti-cancer effects of the serum due to exercise training in these patients with advanced prostate cancer.
The study’s co-author, Dr. Stacey A. Kenfield, assistant professor of urology at UCSF, pointed out the significance of these findings: “These
The study is the first to examine skeletal muscle secretory molecules (myokines) in patients with metastatic castration-resistant prostate cancer (mCRPC). This work supports an acute myokine response to exercise in patients with advanced cancer and that the serum of these patients has a growth-suppressing effect after acute exercise.”
The study’s lead author, Prof. Rob Newton, professor of exercise medicine at Edith Cowan University in Western Australia, said the study shows how important regular exercise is.
“One of the implications of the study is that all cancer patients should try to do high-intensity exercise on most, if not every day of the week, to give their bodies the cancer factors produced by their skeletal muscles,” he told us.
Physical exercise and prostate cancer
Testosterone and other androgens are necessary to maintain the healthy functioning of the prostate. In addition, most prostate cancers depend on androgens and androgen receptors for their growth.
As a result, androgen deprivation therapy, which uses drugs or surgery to reduce androgen synthesis, is used to treat advanced prostate cancer.
However, mutations in prostate cancer cells can lead to the development of resistance to androgen deprivation therapy. Cancers that develop resistance to androgen deprivation therapy are referred to as castration-resistant prostate cancer (CRPC).
Recent studies suggest that physical exercise may help improve the quality of life and physical function of cancer patients. In addition, epidemiological studies have linked exercise to a lower risk of disease progression and longer survival following a prostate cancer diagnosis.
Physical exercise can modulate circulating levels of growth factors, hormones, and cytokines, a class of proteins that can modulate inflammation levels and are involved in maintaining cancer cell growth.
In line with this, studies have shown that serum collected from patients with breast or colorectal cancer immediately after physical exertion can inhibit the proliferation of cultured cancer cells.
How myokines can suppress tumors
These molecules, which can suppress the growth of cancer cells, include myokines, which are cytokines and other proteins that are secreted from skeletal muscle fibers during physical activity.
Myokines help muscles communicate with other organs and are known to have a positive effect on metabolism. There are various types of myokines, including oncostatin M (OSM), acid-risk secreted protein in cysteine (SPARC), irisin, IL6, and IL5. The types of myokines released vary depending on the type, duration, and intensity of exercise.
Studies with individual myokines such as SPARC have shown that these proteins can suppress the proliferation of prostate cancer cell lines. In addition, the researchers observed that serum taken from healthy participants immediately after exercise can inhibit the proliferation of prostate cancer cell lines.
However, cancer patients tend to show declines in muscle mass and other physiological changes that are due to the disease itself as well as to treatments such as chemotherapy.
Additionally, testosterone plays a crucial role in maintaining muscle mass and function. As a result, CRPC patients undergoing androgen deprivation therapy are prone to muscle loss and reduced muscle strength.
Therefore, it is important to determine whether exercise results in elevated serum myokine levels and an increased tumor-suppressive effect of serum in CRPC patients undergoing androgen deprivation therapy, similar to that in healthy individuals.
The study authors had previously shown that serum samples from patients with metastatic CRPC taken after 6 months of high-intensity aerobic and resistance training had elevated serum myokine levels.
The serum taken from these patients also showed an increased ability to suppress the proliferation of a prostate cancer cell line, DU-145, which does not require androgens to grow.
In other words, the study showed that serum obtained from trained advanced CRPC at rest had elevated myokine levels and was better able to suppress tumour cell growth.
In the present study, the researchers investigated whether one-time high-intensity interval training by trained CRPC patients with metastatic disease led to a further increase in serum myokine levels and to tumor-suppressive effects.
34 minutes of HIIT
The study included nine patients with advanced CRPC whose tumours had metastased and who were undergoing anti-androgen therapy. These patients received a supervised, high-intensity exercise program for at least 12 weeks.
On the day of the study, participants took part in a 34-minute HIIT session that included aerobic exercise. The researchers received blood samples from participants two hours before, immediately after and then 30 minutes after the training session.
Serum from mCRPC patients had higher levels of the SPARC, OSM, IL-6 and IL-15 myokines immediately after the training session than the pre-training session. However, this increase was temporary, and the concentration of these myokines returned to pre-workout levels 30 minutes after the training session.
The serum samples that the researchers collected after the training sessions also suppressed the growth of DU-145 cancer cells more than the samples taken at the start of the study before training.
In contrast to their previous study, the present study shows that a single high-intensity aerobic interval training led to a further increase in serum myokine levels and additional tumor-suppressive effects in trained metastatic CRPC patients.
Should all prostate cancer patients do HIIT?
The study authors noted that these findings are preliminary and that further research is needed.
Dr. Murugesan Manoharan, director of urological oncology surgery at Miami Cancer Institute, part of Baptist Health South Florida, who is not involved in the study, warned that “there is evidence that high-intensity aerobic exercise can stimulate myokine response and suppression of tumor growth, which may be useful for metastatic prostate cancer,” but that “no clinically significant conclusion can be drawn from this small study, And that certainly can’t be it will become routine clinical Treatment for metastatic prostate cancer recommended.”
“High-intensity aerobic exercise may not be appropriate for all patients with metastatic prostate cancer. Many of these patients are weak and may cause bone distension. Excessive exercise can lead to significant side effects, including broken bones, dehydration, and kidney failure.”
— Dr. Murugesan Manoharan
The researchers noted that further research is needed to determine the volume, intensity, and type of exercise that is optimal for metastatic CRPC patients.
“The study tested one mode and one dose in trained patients with metastatic cancer. More research is needed to investigate the thresholds for exercise intensity, volume, and mode, as well as any interactions between these exercise-induced myokines and prostate cancer treatment,” said Dr. Kenfield.
“Ideally, each individual patient should be examined by a sports specialist, such as an accredited exercise physiologist, and then a tailored training recipe should be developed that targets the health problems that cause the greatest risk of illness, morbidity and mortality.”
— Professor Rob Newton
“For example, if the patient has sarcopenia (low muscle mass), this really needs to be a priority and a well-designed resistance training program should be carried out to stimulate muscle growth. Dietary support is also important, and involving a dietician in the patient’s team management would be beneficial,” added Prof. Newton.
Similarly, Dr. June Chan, professor of epidemiology and biostatistics at UCSF, who was not involved in the study, remarked: “Recently, the American Cancer Society recommended that cancer survivors seek nutrition and exercise advice and support after diagnosis to better understand how such health habits can maximize their survival.”
“We hope that studies like this and others will help raise awareness of the need for insurance coverage for nutrition and exercise counseling services for cancer survivors,” Dr. Chan added.