Posted on

Treating prostate cancer that has recurred

If metastatic prostate cancer has recurred after surgery and other treatments, a way has been found to increase longevity while undergoing chemotherapy.

Principles of evolution and natural selection, and of game theory, have been used to drive a radical new approach to treating prostate cancer.

Oncologists typically treat aggressive cancers with maximum tolerated doses of anticancer drugs (the limit is there because these drugs also affect normal cells). From an evolutionary perspective, any cancer cells that survive the initial assault have traits that let them resist the drug. An alternative approach called adaptive therapy uses smaller doses that prevent the tumour from evolving total resistance. Tests show that the first round of treatment shrinks the tumour but allows a few cells that remain sensitive to the drug to survive. These cells keep rival, drug-resistant cells from taking over the tumour if it grows back. Subsequent rounds of treatment knocks the tumour size back down.

In this “game”, the oncologists are predators, and the cancer cells are prey. The oncologists’ objective is to kill the prey, or to at least keep it in check. But conventional cancer treatment shifts this balance. By giving a patient repeated strong doses of a cancer drug, the cells are pushed to evolve resistance.

When this occurs, the oncologists stop leading the game and instead have to keep up with an evolving, stronger cancer. By using the algorithm to deploy drugs more subtly, and closely monitoring what the cancer does in response, oncologists can stay ahead for longer.

In trials, this approach has doubled survival times in men with advanced prostate cancer.

See Scientific American, August 2019 “Darwin’s cancer fix” and New Scientist 10 March 2018 “Cancer algorithm uses game theory to double survival time”.

Posted on

Opting for no prostate cancer medical treatment

This article is based on an article by Jill Margo in the Australian Financial Review on 24 May 2019 and my own experience.

When receiving a diagnosis of prostate cancer, some men elect to have no treatment. I know of one who did so, preferring to explore alternative therapies but without success. Anecdotally, after receiving the diagnosis some men never go back to their urologist. It took me nearly seven years to seek treatment after my first PSA test indicated a 50% likelihood that I had prostate cancer (which ultimately was confirmed and by then had spread to my pelvis).

For many men it is confronting to receive a diagnosis of prostate cancer. Some fear that incontinence and impotence will follow treatment – which it often does, at least for a period of time. Also, as with any surgery, removal of the prostate can have negative side effects.

Complicating matters, is the fact that it is currently difficult to predict which cancers will progress. Current estimates based on studies of large numbers of men indicate that 41% of prostate cancers are not destined to cause illness or death. Predictions for any one individual have a high degree of uncertainty and this is a major research topic.

A recent study interviewed eleven men who had biopsy-confirmed prostate cancer and all initially declined surgery or radiation. Most had felt pressured to have surgery and several had been told they would die without treatment – a prognosis that has not yet eventuated.

The psychological wellbeing of some was profoundly affected. Some had relationship breakdowns. Some sought alternative therapies. The careers of some were negatively impacted.

To doctors, the correct decision is not always clear and to reduce risk they sometimes recommend treatment even if there is a chance that it may be over-treatment.

Each man has to make his own decision, in consultation with the doctors and his family and friends.

Prostate cancer is a complex, confronting, and controversial disease. More research is needed to improve the quality of decision making.

My purpose in developing this website is to provide information and to raise money to contribute to the research and support needed to make better decisions.

Posted on

Vitamin D

Vitamin D is needed to help absorb calcium and phosphorus which are essential for bone health.  It can also improve muscle strength and immune function.  It helps to reduce inflammation.  We need to test our level of vitamin D, via a blood test, to ensure that it is not deficient – especially in Australia where we are advised to cover our skin when outdoors so as to avoid skin cancer.

There is also evidence that low levels of vitamin D can be a causal factor in the development of some cancers – adequate vitamin D levels slow the growth of abnormal cells.  Research has also shown that the lower the level of vitamin D, the more aggressive is the prostate cancer (https://www.harvardprostateknowledge.org/low-vitamin-d-tied-aggressive-prostate-cancer).

A 2014 study, “Vitamin D Deficiency Predicts Prostate Biopsy Outcomes” by Adam B. Murphy, Yaw Nyame, Iman K. Martin, et al. (Clin Cancer Res 2014;20:2289-2299), concluded that in African American men, vitamin D deficiency was associated with increased odds of prostate cancer diagnosis on biopsy. In both European American and African American men, severe deficiency was positively associated with higher Gleason grade and tumour stage.

Men with dark skin absorb less ultraviolet light from the sun than men of a lighter complexion, and so tend to make less vitamin D.

I had read about Vitamin D, skin cancer, cholesterol, and prostate cancer in a wonderful 2007 book, “Survival of the sickest” by Dr. Sharon Moalem.   Our skin converts cholesterol to vitamin D when we are exposed to ultraviolet B in sunlight.  Australia’s “Slip-Slop-Slap” anti-skin cancer campaign succeeded in reducing sun exposure and it seems that vitamin D deficiencies rose.  He mentions a growing belief that vitamin D inhibits the growth of cancer cells in the prostate.

Blood tests have revealed my level of vitamin D to be slightly deficient before and after my diagnosis.  I now aim to take 2,000 IU per day.

It seems that exposure to sunlight is important for prevention and containment of prostate cancer and is a factor in keeping the level of cholesterol down – through the action of converting cholesterol into vitamin D.

There is evidence that high-dose vitamin D can prevent progression of prostate cancer for men on active surveillance (the safety of high-doses needs to be confirmed).  Researchers at Macquarie University and Cancer Council NSW are conducting a trial to evaluate the benefits and risks (Prostate News January 19, published by the Prostate Cancer Foundation of Australia).

Posted on

What causes prostate cancer?

In 2010, when I had my first PSA test with a reading of 20, the urologist I was referred to found no irregularity in the rectal examination.  I asked him whether there was anything I could do with regard to diet that would limit risk of developing prostate cancer or lower the risk of any prostate cancer advancing.  He said “No”.  I found this disappointing and it seems that we now know more than he did at that time. 

According to the Australian government prostate cancer website (https://prostate-cancer.canceraustralia.gov.au/home):

Factors that are associated with a higher risk of developing prostate cancer include:

  • age: the risk of developing prostate cancer increases rapidly from age 50
  • family history: men who have a father or brother with prostate cancer are more likely to develop it themselves
  • changes in certain genes that can be carried in families: mutations in the BRCA1 or BRCA2 genes may increase the risk of developing prostate cancer in some men. People with a genetic condition called Lynch syndrome (also called hereditary nonpolyposis colorectal cancer or HNPCC) also have a higher risk of developing prostate cancer.

This is no doubt true, but does not inform men about what they can do to minimise the risk of developing prostate cancer.  The website only provides generic suggestions such as don’t smoke, be sun smart, eat a balanced and nutritious diet, and exercise – none of which are necessarily specific to prostate cancer.

There is a major gap in knowledge here and future posts will delve more deeply into specific causes.  It is an area where more research is urgently needed.

Posted on

Saturated fats increase the likelihood of aggressive prostate cancer

Men who eat more saturated fats are at greater risk of developing aggressive prostate cancer than those with a healthier diet (AFR 7 February 2019).

Fatty acids are taken up into prostate cancer cells, increasing tumour growth.

Researchers at Monash Biomedicine Discovery Institute and University of Melbourne Physiology Department showed that blocking the uptake of fatty acids could slow the prostate cancer’s growth.

Given that prostate cancer has developed in some men and not yet been diagnosed, this is another good reason for men to reduce consumption of saturated fats.  Saturated fats raise blood cholesterol levels and so can increase the risk of heart disease and stroke.

Foods high in saturated fats include beef, lamb, pork, chicken skin, butter, cheese, milk, cream, palm oil, and coconut oil.

Posted on

Can artificial intelligence improve the accuracy of prostate cancer diagnosis?

A report in The Australian (16 January 2019) reports that a tech company (Maxwell Plus) is applying artificial intelligence (AI) to diagnose non-communicable diseases more accurately and more quickly so that doctors could act earlier.  This includes prostate, breast, and lung cancer.  It is also being applied to neurological conditions such as Alzheimer’s.

The analysis uses medical imaging, blood tests, and patient data in their AI algorithms (formulas based on machine learning).  The claim is that by applying AI to images, some of the signs of cancer not detectable to the eye are identified.  AI also allows clinicians and doctors to be more efficient, it is claimed.

This may well be part of the future of diagnosis, especially in cases where the cancer is hard to detect as it can be in some cases or at early stages.  A biopsy would probably still be required to evaluate how aggressive the cancer is before treatment is determined.

Posted on

Prostate cancer statistics #1

Austin, Fred, and I enjoyed a good lunch together in late July 2018.  Our conversation ranged over many topics, one of which was prostate cancer.  We had several things in common:  our ages ranged between 69 and 79; we all felt very fit; we were all still working in our chosen fields and expected to do so for some time; and we had all had been diagnosed with prostate cancer.  Our prostates had been removed and subsequent tests were clear.

We are the lucky ones.  In 2016, 3,243 deaths were attributable to prostate cancer in Australia.  Over 17,000 new cases are diagnosed each year and one in five men will develop prostate cancer by the age of 85.  Furthermore, men diagnosed with prostate cancer are at a 70 per cent increased risk of suicide compared with other men.  More than half of the suicides occur within a year of diagnosis.  It is confronting to receive the diagnosis and one is faced with a complex array of possible treatments.

In 2017 the number of deaths from prostate cancer was 3,275 and the average age at death was 82.3 years.

In 2013, the Australian Institute of Health and Welfare (AIHW) released the first ever comprehensive report on prostate cancer in Australia.  While more men are being diagnosed with prostate cancer, survival rates are high and are improving.

Prostate cancer mortality rates have fallen, from 34 deaths per 100,000 males to 31 deaths per 100,000 between 1982 and 2011.

This drop is projected to continue, expected to fall to 26 deaths per 100,000 males in 2020.

In 2006-2010, the proportion of males who had survived five years after a prostate cancer diagnosis (92%) was higher than for all cancers among males (65%), as well as other leading cancers among males, included melanoma of the skin (89%) and lung cancer (13%).

The annual rate of new cases of prostate cancer rose from 79 per 100,000 males in 1982 to 194 per 100,000 in 2009.

It is expected that the number of cases of prostate cancer diagnosed will continue to increase, reaching 25,000 new cases per year in 2020. This is due to increases in the number of men presenting for testing, changes in diagnostic practices and also the ageing of the population.

The prevalence of prostate cancer increases rapidly from the age of 45, suggesting that men should start regular testing from the age of 40.  This should be via blood tests for the level of prostate specific antigen (PSA).

Given that there is a bulge in the age distribution in the age range 25 to 34, there is a wave of new cases of prostate cancer coming unless we can find ways to reduce the risk of developing prostate cancer.  A significant reduction now seems possible via diet and lifestyle and this will be a major focus of my research.