How exercise stalls cancer growth through the immune system

Staceybee

Albeit a small study and on mice, this supports the case for the benefits of exercise! Always good to another reminder as motivation. I was getting cardio 5 days/wk since my diagnosis 2 yrs ago to the pandemic onset, then fell off the wagon for 6 months when the gym closed and I was working from home like crazy, not going out. But finally paid up for an at-home exercise bike and now back into it. Studies like this remind me of the importance -- plus there is the added benefit from feeling good about being in better shape generally!

https://www.sciencedaily.com/releases/2020/10/2010...

How exercise stalls cancer growth through the immune system

Date:

October 26, 2020

Source:

Karolinska Institutet

Summary:

People with cancer who exercise generally have a better prognosis than inactive patients. Now, researchers have found a likely explanation of why exercise helps slow down cancer growth in mice: Physical activity changes the metabolism of the immune system's cytotoxic T cells and thereby improves their ability to attack cancer cells.

"The biology behind the positive effects of exercise can provide new insights into how the body maintains health as well as help us design and improve treatments against cancer," says Randall Johnson, professor at the Department of Cell and Molecular Biology, Karolinska Institutet, and the study's corresponding author.

Prior research has shown that physical activity can prevent unhealth as well as improve the prognosis of several diseases including various forms of cancer. Exactly how exercise exerts its protective effects against cancer is, however, still unknown, especially when it comes to the biological mechanisms. One plausible explanation is that physical activity activates the immune system and thereby bolsters the body's ability to prevent and inhibit cancer growth.

In this study, researchers at Karolinska Institutet expanded on this hypothesis by examining how the immune system's cytotoxic T cells, that is white blood cells specialized in killing cancer cells, respond to exercise.

They divided mice with cancer into two groups and let one group exercise regularly in a spinning wheel while the other remained inactive. The result showed that cancer growth slowed and mortality decreased in the trained animals compared with the untrained.

Next, the researchers examined the importance of cytotoxic T cells by injecting antibodies that remove these T cells in both trained and untrained mice. The antibodies knocked out the positive effect of exercise on both cancer growth and survival, which according to the researchers demonstrates the significance of these T cells for exercise-induced suppression of cancer.

The researchers also transferred cytotoxic T cells from trained to untrained mice with tumors, which improved their prospects compared with those who got cells from untrained animals.

To examine how exercise influenced cancer growth, the researchers isolated T cells, blood and tissue samples after a training sessions and measured levels of common metabolites that are produced in muscle and excreted into plasma at high levels during exertion. Some of these metabolites, such as lactate, altered the metabolism of the T cells and increased their activity. The researchers also found that T cells isolated from an exercised animal showed an altered metabolism compared to T cells from resting animals.

In addition, the researchers examined how these metabolites change in response to exercise in humans. They took blood samples from eight healthy men after 30 minutes of intense cycling and noticed that the same training-induced metabolites were released in humans.

"Our research shows that exercise affects the production of several molecules and metabolites that activate cancer-fighting immune cells and thereby inhibit cancer growth," says Helene Rundqvist, senior researcher at the Department of Laboratory Medicine, Karolinska Institutet, and the study's first author. "We hope these results may contribute to a deeper understanding of how our lifestyle impacts our immune system and inform the development of new immunotherapies against cancer."

The researchers have received financing from the Knut and Alice Wallenberg Foundation, the Swedish Research Council, the Swedish Cancer Society, the Swedish Childhood Cancer Foundation, the Swedish Society of Medicine, Cancer Research UK and the Wellcome Trust.

WC3

Staceybee:

Interesting study. I was exercising a lot before my diagnosis. I'm not sure what, if any effect it had on the cancer but I read an article from fredhutch.org that discussed the science of metastasis and noted that carcinoma cells can only survive for about three days in the turbulent environment of the blood stream. I'm sure the relation between exercise and cancer suppression is actually complex but I do wonder if one of my many brisk walks prevented any incidents of metastasis by increasing the rate of blood flow and making cancer cells less likely to survive my blood stream.

Here is the article if you are interested.

The Science of Cancer Spread

moth

I exercised lots before my stage 1 diagnosis and even more after. Still had a recurrence & metastatic spread

Not to discourage anyone and I'd still recommend it as one of the top evidence-based interventions but cancer is a wily bastard so there are no guarantees.

MountainMia

Yes, moth, I was in the best shape of my life before my diagnosis, with both cardio and weight training. I don't know if it did me any good in terms of cancer prevention, but I do think it probably help be recover from treatment more easily.

MinusTwo

Me too - best weight, best strength, best diet, best exercise every day, least stress.... While I agree that exercise is a great thing, it certainly didn't "stall" my cancer growth - either the first time or the with the recurrence.

1redgirl

After my mastectomy, refused chemo, radiation and hormone therapy, I had to give up riding horses and took up biking. My right arm with 12 lymph nodes gone is just not strong enough to handle any quick motions etc., that is needed in horse training. Too painful. The desire to ride horses has however intensified as I moved this year into a horse community. I am surrounded by what I love. I am lucky. I bike around 30 miles a day. Swim everyday. I also walk a lot, help a friend with her horse so I get a lot of exercise. I believe in my heart it is what has kept me alive the past couple years. I still refrain from eating sweets or anything with lots of sugar. I have kept my weight off as well. I still fast everyday for at least 13 hrs.

The exercise relieves my stress. I believe stress is what caused my cancer 25 years ago, and what did so again 3 years ago. I have written on this board a few times about stress. It is something I battle everyday. When I look back on what commitments I once agreed to, I am horrified. It is amazing I survived.

I always said the day I quit riding horses I would die. I was lucky I found biking to be a nice replacement. I have met so many nice people due to my biking. I have seen so many wonderful sights.

God is good. Have faith.

Onlyme64

So, me exercising my butt off, trying to lose weight, which is very slow, only 17lb since July, eating healthier, limiting my alcohol.. doing everything the doctor is telling me will do nothing to prevent a recurrence?

so what is the point of doing anything of that, seems like it will come back no matter what.... so why stress over doing a damn thing...

so disappointing...

Peregrinelady

Justme, I think what you are seeing here is that there is no guarantee that exercise will prevent a recurrence, but studies have shown that it can cut your chances of recurrence by 40%. Plus it benefits your health in many other ways. Losing 17 lbs since July is a very reasonable, admirable weght loss. Keep up the good work!

Onlyme64

Well I will take the cut my chances by 40%, but what is concerned a good amount of time to exercise weekly? I was exercising about 300 minutes a week, but I have bad knees and irrigated it so no exercise for a few more days. So what is the normal hours of weekly exercises for the recurrence by 40%.

MinusTwo

justme - as Peregrine says - there is NOTHING that is guaranteed to keep you from getting cancer in the first place OR from getting a recurrence. Being healthy certainly gives you a better chance to avoid medical issues. Getting your weight under control is a great goal. Congrats on your 17 lb loss.

You have to determine with your docs what is best for you. How much exercise and what foods to avoid (due to high BP &/or cholesterol or diabetes, etc.) and how much sleep you need, what other physical issues you have, etc.

So you were exercising 5 hours a week? Around 45 minutes a day? I found that a recumbent bike was easier on my knees than one where I had to sit up straight. You might try that. And riding a recumbent bike allows you to read while you're "working". Also you could do yoga or lift light weights or join a Silver Sneakers chair exercise program. There are many things available.

MountainMia

justme, I find it discouraging, too. I get what you're saying. Here's how I figure it: I can reduce my risk by exercising and eating a healthy diet, getting enough sleep and managing stress. I don't know if it's enough. I'll NEVER know if it's enough, unless I never have a recurrence. (If I DO have a recurrence, maybe it was later because of my good habits, right?) So. I'll never know.

What I DO know is the healthy habits put me in a better position to deal with recurrence, if it happens. If my body and spirit are sturdier and more resilient, I will get through any treatment more easily, maybe more successfully, than if I'm less healthy. And being the right weight, eating well, exercising, will also reduce my risks of many other illnesses like heart disease, diabetes, etc.

So yeah, it's discouraging to not know if we're doing enough, or if we're doing just the right things, or the right amount of them. It honestly makes me feel kind of helpless. But I'm not actually helpless, not matter how it feels. I AM helping myself by making the effort to be healthy, regardless of if I have a recurrence.

Big congratulations on your weight loss and all the other stuff you're doing to be strong. You rock. Please give yourself a big pat on the back. See if you can find some healthy way to reward yourself. You deserve it!

Onlyme64

thanks everyone making me feel I am doing what I can to reduce the risk.. with hurting my knee, no exercising started to freak me out because I know that is good for reduce your risk. Never thought of chair exercising.

ShetlandPony

I agree, MountainMia! And if there is a recurrence, it helps to know you did what you could so no regrets.

To answer your question, justme, about how much exercise, I am copying part of a post Zarovka made on these boards:

The article Lifestyle modifications for patients with breast cancer to improve prognosis and optimize overall health summarizes the data on lifestyle changes on survival outcomes. It is worth reading in its entirety, but here is a summary of key points.

Exercise and maintaining your ideal body weight are the most important lifestyle interventions you can do if you want to decrease your risk of breast cancer recurrence and death. Physical activity (150 minutes per week, moderate intensity) can reduce the chance of death from breast cancer by up to 40%.

Two analyses showed a substantial inverse dose–response effect between hours per week engaged in physical activity and breast cancer mortality.26,27 Similar beneficial metabolic effects have been shown for both aerobic and resistance exercise, but optimal results are achieved with a combination of the two.22

Also from that article:

Patients should be encouraged to engage in at least 30 minutes of moderate-intensity physical activity at least five days of the week, or 75 minutes of more vigorous exercise, along with two to three weekly strength training sessions, including exercises for major muscle groups. This recommendation has been endorsed by both the Canadian Cancer Society24 and the American Cancer Society.25 However, more hours of exercise (but not more vigorous activity) may have increased benefit.

MountainMia

Thanks for the link, ShetlandPony. I've seen some of this before but I don't think I've ever seen the summary of it all.

MinusTwo

justme - check out the Silver Sneakers program. Although it was developed for seniors, it's great exercise for anyone. Usually an hour twice a week. Chair based so the "aerobics" are standing next to your chair. Stretching & lifting light weights. You never have to get down on the floor. I know if you have an LA Fitness membership, anyone is welcome. Most YMCAs have at least the "classic" classes and there are many community based locations - like at churches or service centers. Many insurance companies cover the cost.

https://tools.silversneakers.com/

Onlyme64

ShetlandPony thanks for the link, I will take a look at it. Again, i just want to make sure I am doing everything possible to reduce the risk. I wish they could say what caused it, was it my weight, my drinking, no eating healthy, lack of exercise.... I know they can't but wish they can. Just gets me, my sister drinks way more then I ever did, does not exercise, not eating healthy and well now weighs more then me... she did not get it, but I did. I been resting my knee, it is feeling better, so I am going to ease back into exercise.... I am not going to give up on trying to keep the risk of recurrence down.

As for exercise, I was going to a program at the gym, but I am not going to the gym until after this covid is more under control.. So I am limited on any using weights. Using ankle weights at home put too much on my knee and that is what did that in. I have bad knees and my doctor told me if I don't take it easy I will end up with knee replacement.

LillyIsHere

Thank you for the link SP. My kid has a question: if exercise cuts the risk 40% and letrozole another 50%, does it mean both of them cut the risk 90%? It sounds too good to be true but I didn't give her an answer.

ThreeTree

LillyIsHere - I too have wondered about those percentages. I've heard that Letrozole gives 30-50%; exercise 30-40%. Then if you add other things like keeping your weight down, eating certain foods, and maybe taking certain supplements, etc. that all are said to reduce risk by a certain level, you can wind up with an over 100% risk reduction. I remember being told that the chemo was going to lower my risk by some percentage and adding the radiation and surgery would add even another percentage. Again, at some point you wind up with well over a 100% risk reduction if you actually do all of the suggested things. Somehow I just don't believe that can be true, or people would not be relapsing nearly as much as they do.

Also, I've read where some on these boards have been told it's OK to skip AI's if they make sure to exercise and keep their weight down, because it provides about the same amount of risk reduction. So are they saying one risk reduction replaces the other, or if combined, multiple risk reduction factors all add up to a larger risk reduction. I'm not good at all with statistics, but my take is that there is something way off here.

moth

I think part of the confusion is mingling absolute risk versus relative risk. BCO has a little series explaining the basics of risk stats.

This page goes over the realtive v absolute https://www.breastcancer.org/risk/understand/abs_v...

Then a nice page with examples & numbers https://www.breastcancer.org/risk/understand/examp...

The following page has a long list of risk factors & the one that I think many of us are not aware of is that *separate* from recurrence risk, having had breast cancer once increases risk of another breast cancer 3-4 times. https://www.breastcancer.org/risk/factors

So taking steps to reduce our risk in all possible ways is IMO important. BUT no, you cannot add these add up and end up with 0 or negative % risk. I wish it worked that way because if it did, I should have been in the negative crowd

Staceybee

Also don’t forget about the percentage math. For example, ifthe AI takes your recurrence risk down to 20% and exercising cuts that by 30% that would shave off 6pts and you still have 14% risk. And of course these are all far from precise. Point is there is some statistical evidence that regular exercise on average moves people in the right direction and some preliminary lab data to help explain why on a cellular level.

ThreeTree

Moth - thanks for posting the links. I'll take a look at them when I think my brain is in a better place. The letrozole causes so much brain fog, it is hit and miss for me throughout the day as the whether I can comprehend anything "deep" or not. Even without the brain fog, I start getting lost with relative and absolute risk. It's one of those things that I can follow while I'm reading about it or while it's being explained to me, but then just by a few hours later, I've lost it. Math and science were like that for me in school. I could follow along while the teacher explained everything, but by the time I was home and attempting homework problems, I wasn't connecting anymore. No surprise that I was a social sciences major. I can get the gist of the statistical stuff and generally appreciate what it all means, but on an individual and specific level, it just draws blanks from my mind a good deal of the time. I know we can't have more than 100% risk reduction unless they find a true cure, but it sure seems on the surface level as if doing all these things they suggest should get you to at least 100%.

PrincessButtercup

Moth, I'm so sorry to read your update. I haven't been on for a while, but I remember we were both in the Dec 2017 surgery group. I stopped in today to look up something up and stumbled over this thread.

Gosh I'm rooting for you. Rooting for all of you.

PrincessButtercup

This thread also gets to some of my questions. Thanks for the links.

Onlyme64

Ok, I thought I was the only one thinking, taking anastrozole, reduces 50%, radiation 70%, exercising 40%, weight lose as of now, down another pound, 18lb, 16% reduction. in my mind, I am covered on 176% risk recurrence in the breast that I had the cancer and 106% risk reduction for all over the body.. oh and I am taking zometa which studies have shown reduction to the bones. Again, in my mind, I am trying to do everything to keep the recurrence risk down.

I did read and listened to the pod cast which was posted on this thread and they said that women are more likely to die from cardiac/heart attack then breast cancer. Again in my mind, now I am getting in the best shape I can which will help my overall health.

moth

hey princess buttercup! Glad to see you doing well!!

Yeah, I totally drew the short straw. I'm still so bitter you could bottle up my tears and sell them as the additive to prevent poisoning....but I'm still here and starting a new clinical trial soon.

Btw, here is a post of mine from June 2019 - exercise and tea for reducing recurrence risk specifically for triple neg. Reference links inside

https://community.breastcancer.org/forum/72/topics...

I can say I did all I could think of so at least no regrets or 2nd guessing past me.

Keep on moving, amigas!

cm2020

moth......Hugs. Lots of hugs.

PrincessButtercup

Moth, my husband is on immunotherapy for Multiple Myeloma, and it has been a game changer. May it be so for you, as well! Big hugs. And good luck on your clinical trial. Will be thinking of you.