"Treating Advanced Prostate Cancer with Diet: Part 2"
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.
The 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, we might as well give diet a try.
So, they 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, consumption 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, sunflower, safflower, and cottonseed,
and also comes preformed in animal-based foods,
particularly in 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:
9 of the 10 patients showed an apparent slowing of cancer growth,
and 4 of the 9 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 10 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, the researchers 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 earlier period,
and indeed, at the end of three months, on average, there was PSA reversal.
So, changes in the rate of PSA rise were like opposite that of whole plant food intake,
raising the provocative possibility that PSA may have been 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 refuting the benefits of standard therapies
and not guaranteeing 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.