Treating Advanced Prostate Cancer with Diet: Part 2

Michael Greger M.D. FACLM · August 25, 2017 · Volume 37

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What happens when metastatic prostate cancer patients were taught to increase intake of whole grains, vegetables, fruits, and beans, and to decrease consumption of meat, dairy, and junk?

Discuss

Transcript

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Dr. Ornish and colleagues were able to show an apparent reversal in the progression of early stage localized prostate cancer with a plant-based diet and lifestyle program, and researchers at the University of Massachusetts and elsewhere showed a similar diet may help slow the progression of even advanced prostate cancer over a period of four months. How about six months? Researchers at UC San Diego found more cancer patients in the same situation, and put them through the same protocol. These were patients who were already treated for “invasive prostate cancer…by [either] radical prostatectomy or radiation therapy,” yet had “rising PSA” levels, suggesting the treatment didn’t work, and the cancer was on the move.

In those with a cancer recurrence, PSA levels typically “rise exponentially…, reflecting the gradual, inexorable growth of the cancer in the body.” “[T]he rate of [this] PSA rise is the single best predictor of…the…development of overt metastatic disease, as well as of overall survival.” The next step would be what’s called “hormonal therapy,” which is chemical or surgical castration, which has a list of side effects, including loss of libido, and sexual function, and strength, and vitality. Therefore, we try to hold off on that for as long as possible. So, if we’re just waiting, might as well give diet a try.

So, “[t]hey were taught to increase intake of whole grains, vegetables, fruit, and [beans], and to decrease meat, dairy, and refined [carbs].” Of all possible lifestyle interventions, why a whole food, plant-based diet? Well, if you look around the world, there are huge differences in prostate cancer rates, with “We’re #1, USA, USA” rates up to a hundred times higher than some places in Asia, for example. And, it’s not just genetic; within one generation of coming to the U.S., cancer rates shoot up, and the grandkids end up with the same top-of-the-pile rates. A whole range of “lifestyle factors” have been looked at, but diet appears to have the greatest influence. Specifically, “[c]onsumption of meat and dairy…appears to increase risk, and consumption of plant…foods appears to decrease risk.” Hence, the plant-based diet.

“A possible mechanism…is arachidonic acid,” an inflammatory compound which we make from omega-6 rich oils, like corn oil, sunflower, safflower, and cottonseed oil, and also comes “preformed in…animal-based foods”—particularly from chicken in the American diet, and also eggs. And, in a petri dish, at least, arachidonic acid appears to stimulate prostate cancer cell growth as much 200%. But, ask men to remove processed and animal foods from their diet for six months, and what happens?

This is the before. This is how fast their PSA levels were rising before starting the study. In the absence of treatment, levels of PSA tend to increase exponentially, but eating healthier, this happened: nine of the ten patients showed an apparent slowing of cancer growth, and four of the nine an apparent reversal in cancer growth. The average “doubling time”—an estimate of how long it takes for their cancer to double in size—slowed from doubling every year, to closer to every ten years.

There’s been other studies using various diets and nutritional interventions, like vitamin supplements, but none have worked as well as this one. And, their compliance wasn’t even all that great. They did good about boosting their whole grain consumption, especially in those first three months, but then backslid a bit. They did eat more vegetables, including a serving of greens, and an extra serving of fruit—at least early on—and at least ate one whole serving of legumes a day, when they started. So, they “did observe some [dietary] recidivism by” the end of the study. The patients started out stronger, but then started to slide back into old habits.

So, the researchers checked to see if maybe they were better able to beat off the disease during that early period, and indeed, at the end of three months, on average, there was PSA reversal. So, “[c]hanges in the rate of [PSA] rise” were like “opposite” that of whole food plant intake, “raising the provocative possibility that PSA may have [been like tracking those changes,] suggesting that [the] adoption of a plant-based diet may have therapeutic potential in the management of [recurrent prostate cancer].”

Their “findings suggest” that without further surgery, radiation, or chemo, “disease progression” can be slowed, or even reversed, despite the “prevailing scientific consensus…that cancer progression is largely irreversible.” They’re “not refut[ing] the benefits of standard therapies,” and not “guarantee[ing] that a plant-based diet and stress reduction will always induce remission. But [the results] do contribute to [this] growing [medical] literature that…in at least some circumstances, cancer may be partly reversible.” Just by modifying “dietary and lifestyle factors”, men “may be able to prevent disease spread”—all without getting their testicles chopped off.

Please consider volunteering to help out on the site.

Sources

Acknowledgements

Image credit: Sally Plank via Flickr. Image has been modified.

Motion graphics by Avocado Video.

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Dr. Ornish and colleagues were able to show an apparent reversal in the progression of early stage localized prostate cancer with a plant-based diet and lifestyle program, and researchers at the University of Massachusetts and elsewhere showed a similar diet may help slow the progression of even advanced prostate cancer over a period of four months. How about six months? Researchers at UC San Diego found more cancer patients in the same situation, and put them through the same protocol. These were patients who were already treated for “invasive prostate cancer…by [either] radical prostatectomy or radiation therapy,” yet had “rising PSA” levels, suggesting the treatment didn’t work, and the cancer was on the move.

In those with a cancer recurrence, PSA levels typically “rise exponentially…, reflecting the gradual, inexorable growth of the cancer in the body.” “[T]he rate of [this] PSA rise is the single best predictor of…the…development of overt metastatic disease, as well as of overall survival.” The next step would be what’s called “hormonal therapy,” which is chemical or surgical castration, which has a list of side effects, including loss of libido, and sexual function, and strength, and vitality. Therefore, we try to hold off on that for as long as possible. So, if we’re just waiting, might as well give diet a try.

So, “[t]hey were taught to increase intake of whole grains, vegetables, fruit, and [beans], and to decrease meat, dairy, and refined [carbs].” Of all possible lifestyle interventions, why a whole food, plant-based diet? Well, if you look around the world, there are huge differences in prostate cancer rates, with “We’re #1, USA, USA” rates up to a hundred times higher than some places in Asia, for example. And, it’s not just genetic; within one generation of coming to the U.S., cancer rates shoot up, and the grandkids end up with the same top-of-the-pile rates. A whole range of “lifestyle factors” have been looked at, but diet appears to have the greatest influence. Specifically, “[c]onsumption of meat and dairy…appears to increase risk, and consumption of plant…foods appears to decrease risk.” Hence, the plant-based diet.

“A possible mechanism…is arachidonic acid,” an inflammatory compound which we make from omega-6 rich oils, like corn oil, sunflower, safflower, and cottonseed oil, and also comes “preformed in…animal-based foods”—particularly from chicken in the American diet, and also eggs. And, in a petri dish, at least, arachidonic acid appears to stimulate prostate cancer cell growth as much 200%. But, ask men to remove processed and animal foods from their diet for six months, and what happens?

This is the before. This is how fast their PSA levels were rising before starting the study. In the absence of treatment, levels of PSA tend to increase exponentially, but eating healthier, this happened: nine of the ten patients showed an apparent slowing of cancer growth, and four of the nine an apparent reversal in cancer growth. The average “doubling time”—an estimate of how long it takes for their cancer to double in size—slowed from doubling every year, to closer to every ten years.

There’s been other studies using various diets and nutritional interventions, like vitamin supplements, but none have worked as well as this one. And, their compliance wasn’t even all that great. They did good about boosting their whole grain consumption, especially in those first three months, but then backslid a bit. They did eat more vegetables, including a serving of greens, and an extra serving of fruit—at least early on—and at least ate one whole serving of legumes a day, when they started. So, they “did observe some [dietary] recidivism by” the end of the study. The patients started out stronger, but then started to slide back into old habits.

So, the researchers checked to see if maybe they were better able to beat off the disease during that early period, and indeed, at the end of three months, on average, there was PSA reversal. So, “[c]hanges in the rate of [PSA] rise” were like “opposite” that of whole food plant intake, “raising the provocative possibility that PSA may have [been like tracking those changes,] suggesting that [the] adoption of a plant-based diet may have therapeutic potential in the management of [recurrent prostate cancer].”

Their “findings suggest” that without further surgery, radiation, or chemo, “disease progression” can be slowed, or even reversed, despite the “prevailing scientific consensus…that cancer progression is largely irreversible.” They’re “not refut[ing] the benefits of standard therapies,” and not “guarantee[ing] that a plant-based diet and stress reduction will always induce remission. But [the results] do contribute to [this] growing [medical] literature that…in at least some circumstances, cancer may be partly reversible.” Just by modifying “dietary and lifestyle factors”, men “may be able to prevent disease spread”—all without getting their testicles chopped off.

Please consider volunteering to help out on the site.

Image credit: Sally Plank via Flickr. Image has been modified.

Motion graphics by Avocado Video.

Doctor's Note

Healthy diets work only if you eat them. Check out the earlier study in my last video, Treating Advanced Prostate Cancer with Diet: Part 1.

You may also be interested in:

Why is it so hard to get men to change their diet—even in the face of cancer? Watch Changing a Man’s Diet After a Prostate Cancer Diagnosis.

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