Tag Archives: prostate cancer

What we see and what YOU get.


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Will Rogers is said to have stated, “When the Oakies left Oklahoma and moved to California, it raised the IQ of both states.” This story has given rise to the concept of the “Will Rogers phenomenon” in medicine that is very well explained in this essay. Basically, it provides a cautionary message when evaluating new therapies in cancer medicine, because if a new study has taken advantage of newer diagnostic techniques to eliminate some of the patients with higher risk (say those with metastases), then it could easily be that an improved result is not from the new therapy, but from the ability to throw out the higher risk patients from a study cohort.

We are certainly at risk of this now in prostate cancer. In the last 5-10 years, a number of more sensitive scans have been introduced that can reveal metastatic deposits previously missed by standard technetium-99m bone scans or CT scans. Most of these rely on the technology known as PET (positron emission tomography) scanning. The first clinical PET scans mostly utilized glucose to which a positron emitter, Fluorine-18, was attached. For bone metastases, it is easy to see how much more sensitive F-18 scans are as shown in this image: (Same patient – A. “Regular” Tc-99m bone scan  B. NaF-18 PET scan)

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Suppose you have a new treatment that is for patients “with 10 or fewer” bone metastases. If you are comparing the new treatment with one that was used in the past, and you now use the PET scan (on the right), this patient would not be eligible, whereas in the past (old scanning technique) he would have been. He clearly has a higher tumor burden than 10 metastases. Hence, he is now eliminated from the new study, and therefore the new study will automatically look better in terms of outcome than previous treatments. This is called “stage migration” or the “Will Rogers phenomenon”.

For “soft tissue” metastases (lymph nodes, liver, lung, etc.) the regular Fluorodeoxyglucose FDG-PET scans were approved decades ago for lung cancer, colon cancer, lymphomas and breast cancer but they never worked well for prostate cancer. A simplistic explanation may have to do with the different metabolism of prostate cancer which tends to utilize lipid rather than glucose for energy. (see our study here). Therefore researchers looked for other metabolites that would light up prostate cancer. Acetate and choline could be labelled with Carbon-11 and worked well. However, C-11 has a half life of only 20 minutes, so making the label in a cyclotron had to be done essentially in the room next door to the scanner and injected immediately into the patient. Another metabolite taken up by prostate cancer, an artificial amino acid (fluciclovine), could be labeled with F-18, worked well and has now been approved, called the Axumin scan.  Potentially even better will be the PSMA scan, now in research mode.

The net result of these new scans is to allow physicians to answer the frequent question patients ask, “Where is the PSA coming from?” The problem then becomes the title of this essay – What we see and what You get. There are numerous scenarios. For example, a patient who comes in with a very aggressive Gleason 9 cancer and a PSA of 12.3. Should we go immediately to a routine bone and CT scan, or just order an Axumin scan? And if we find 2 positive spots, one in a rib and the other in a lymph node, does that mean the patient can’t be cured?? Five years ago, we would have never known about the metastases and we would have operated or used radiation therapy in a curative attempt. Screen Shot 2019-04-09 at 9.56.43 PMWhat about the patient with a rising PSA 5 years after he had surgery. We do a PSMA scan and find a solitary node near the left iliac artery. Should we irradiate the node? What about operating and removing it – remember, it may not look any different from all the other nodes to the surgeon. Which one should he/she take out? And what is accomplished by these efforts? Should the PSA go down (yes if that’s the only metastasis) and what to do if it doesn’t go down. Are we playing “whack a node”? How many times do we go after spots that keep showing up, versus starting some sort of hormone therapy?

There is an excellent article addressing some of these questions written by my good friend Chris Sweeney and colleagues that you can read here. A summary quote from their article states, “Given the current limited understanding of how reliable these scans are in predicting the need for appropriate management change, data-driven guidelines and standardized consensus approaches are more critical than ever.” A review of some of the early attempts to treat a small number of metastases (called oligometastatic disease) has just appeared here. One example of a paper reporting interesting results is summarized as follows: “Of the retrospective reports, the largest includes 119 treatment‐naive patients who had ≤3 sites of oligorecurrence and received SBRT to all involved sites, with 92 of 119 (77%) undergoing pretreatment choline PET. The 3‐year distant PFS [progression free survival] rate of 31% and the 3‐year OS rate of 95% are favorable and suggest a subset of patients likely benefitted from aggressive local therapy; however, conclusions from these data are limited in the absence of a comparative control arm.”

Maybe we simply have to refer back to another quote from Will Rogers, “America is a nation that conceives many odd inventions for getting somewhere but it can think of nothing to do once it gets there.” Stay tuned…

 

 

 

 

 

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Filed under General Prostate Cancer Issues, Oligometastatic prostate cancer, Prostate cancer therapy, Targeted treatment

Black holes and genetic laws


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I just finished reading Stephen Hawking’s last book, Brief Answers to the Big Questions, which I found more accessible than A Brief History of Time, written more than 30 years ago. Hawking’s abilities to explain the very (for me) abstract concepts of how no information can flow out of black holes and that the amount in there is somehow directly related to the cross sectional area of the hole was satisfying. As a very math challenged individual, I’m also a fan of Heisenberg and the perplexing issue that in the quantum/wave world of particle physics, you just can’t be certain about position and momentum. Yet, there are certain laws, like the speed of light, that are never violated, at least in the universe we live in.

So what does this have to do with genetics and prostate (or other) cancers? Here is a law: A always pairs with T, and C always pairs with G. In our biologic universe, without this law, no life as we know it could exist (prions may be an exception, but that gets too far into the definition of “life”). Yet, just as with the uncertainty of Heisenberg, the base pairing in DNA/RNA is not completely inviolable. Mistakes are made…and this can result in cancer. Cancer is a genetic disease and for anyone who hasn’t read it, I still recommend you avail yourself of the incredibly well written book, The Emperor of All Maladies. In the short time since that book was written, the explosion in our understanding of how genetic errors and cancer are related has been difficult to keep up with. The Cancer Genome Atlas (clever name, eh?) is but one example, and its use by scientists skilled in math (ugh) continues to help classify cancers based on how their mutations drive them rather than just how they look under the microscope or which organ they started in. Here is the math and the results one such analysis has on predicting survival for stomach cancer:

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As you can see, the prognosis and potentially the treatment for one subtype of “stomach cancer” might be very different for one patient than for another. Bringing this technology to prostate cancer, we already know the mutational landscape is vast. For example, this article looked at 1,013 different prostate cancers and found 97 significantly mutated genes, including 70 not previously recognized, and many present in <3% of cases. There is hidden good news in this story, in that the same mutational uncertainties that can give rise to cancer (breaking the law of AT-CG) also allows our immune systems to react to the novel mutated proteins that cancers now display. For an interview from this week’s NEJM on gene editing, click here.

Keeping up with this world of laws, broken laws, and “black holes” will be a remarkable challenge for patients and oncologists alike. My final recommendation for reading about this is a terrific article you can find here by George Sledge, one of the outstanding leaders in our field. He notes that even the most skilled oncologist, paired with the smartest of patients, will be unable to keep up. But remember this, you can’t go faster than the speed of light. That’s the law!

 

 

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It’s MO time – please help!


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In my career fighting for the cure of prostate cancer, two organizations (besides the National Cancer Institute) have been outstanding partners. Movember was started by a couple of friends in a bar in Australia. This became the answer to a long standing jealousy of mine for something as popular and effective as the Susan G. Koman Foundation and Race for the Cure. I often refer to our prostate cancer journey when I lecture by noting how we “crawl for the cure” while our sisters are racing. In 2016, the NCI budget for breast cancer research was $519.9 million, more than twice as much as that for prostate cancer at $241 million. This, in spite of the fact that prostate cancer deaths this year are 3/4 as common (29,430) as breast cancer deaths (40,920). It’s not a contest really, since all cancer research is moving the field forward rapidly, but Movember has been incredibly helpful in sponsoring research and advocating for us.

The other organization, Prostate Cancer Foundation, shows how much a single individual with great connections and personal motivation can do. Michael Milken deserves enormous credit for his vision and leadership. I personally benefited from grants given out by the foundation, and even more from their amazing annual meeting that draws together prostate cancer researchers from around the world to share data and ideas. Dr. Howard Soule is a key factor in PCF’s incredible success and his name should be as well known as Susan G. Koman in my view.

I hope you will join with all of us in fighting for the cure in prostate cancer. Grow one, or support someone who is growing, and tell your friends. The progress and future has never been brighter, and our hairy upper lips should show it!

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A perfect death


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This week in which the country will come together to mourn the passing of a true American original, John McCain, it might be worth considering our (your) own mortality. Even as the ongoing progress toward controlling prostate cancer is underway, it remains clear that “something else” will get us. As an example, in a study I was privileged to lead among patients with high risk prostate cancer, other cancers (many of which were caused by our adjuvant mitoxantrone treatment) were as likely to lead to death and prostate cancer was the cause of dying only ~20% of the time

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As oncologists, we face the “end of life” issues more frequently than most physicians, and certainly deal with the reality of death more than folks in most other professions. I distinctly remember one lovely woman in her 50’s who was very open in discussing her wishes. She wanted to die while lying on her favorite beach in Florida watching the sunlight sparkling on the ocean – not an easy thing to arrange (and it didn’t happen). My own fantasy would be to have a lovely vacation in Hawaii (without this week’s rain) with my entire family, say my good-byes as I put them all on the plane, and stay over an extra day to pay for the hotel and be sure all of my financial affairs were up to date – then die of a heart attack on the way home the next day. Perfect. The airline would be carrying my carcass home for the mere cost of a coach seat and I wouldn’t even have to suffer that long in the crunched position with no leg room.

Short of these fantasies, however, I recently undertook an exercise that anyone could do and I herewith commend to you as well. My wife and I were lucky enough to score tickets to the London production of Hamilton last February. In it, there were two numbers that grabbed me by the heart. First was Washington’s “teach ’em how to say goodbye” song, “One Last Time”. As with John McCain’s final commentaries over the past few months, Hamilton’s farewell speech written for Washington was masterful (as is Lin-Manuel Miranda’s reprise).

But the song that most moved me to tears (and action) was “Who Lives, Who Dies, Who Tells Your Story”. After listening to it about a dozen times, I realized that we all have a story. It may not be as honest/noble as John McCain’s, or as consequential as Hamilton’s or Washington’s, but for some small group of your relatives or children or grandchildren, your story will have special meaning. If you don’t write it, your memories of your father, your grandfather, your family in general will die with you. In my case, I read a couple of autobiographies, self-published, from friends/acquaintances and decided that their stories were highly personal, and not terribly interesting. But when I started writing the story of my own grandfather and father, and my story, it was a joyful experience of reliving many happy memories, and a way of reconnecting with my first love affair, our children’s births, and the many blessings that have come my way. The result is not a literary masterpiece, but I am going to have it bound and give a copy to each of my kids to gather dust on their bookshelves.

In the arc of history, some things have not changed. “Our days may come to seventy years, or eighty, if our strength endures; yet the best of them are but trouble and sorrow, for they quickly pass, and we fly away.” (Psalm 90:10). Although trouble and sorrow are a part of life (and of dying), there can be real joy in pausing to appreciate all life has given you. Carpe diem!

 

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The Hits Just Keep on Coming


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I have a hiking companion who loves math, computers, and to a large extent, eugenics. He posits that we will eventually understand the human genome so well that we will be able to make all humans “smart” or “better” through genetic engineering. I argue back endlessly, with little success, that his definition of “smart” and “better” may not be shared  by everyone (he counters that these definitions will be left to the parents…) and that there will be unintended consequences of diving into our DNA with CRISPR/Cas9 technology.

The wonderful complexity of humankind is, of course, reflected in every single cell in our bodies and in all of our cancer cells as well. The debate over the number of synapses (or permutations) in our brains versus atoms (or stars etc.) in the observable universe is well beyond my comprehension. Unfortunately the “much simpler” question of how many things go wrong in cancer cells is also mind boggling. Hence, the phenomenal work of one of the West Coast Dream Team’s recent publications is not surprising. A reductionist view is shown in this diagram from their paper published last month:

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The scientific team, using funds from PCF, SU2C, and Movember (among others), did a whole genome analysis of metastatic tumor specimens from 101 men with castration resistant (hormone insensitive) prostate cancer. There is an excellent report on this work from the UCSF News Center here. Lest you believe that the results have resulted in an “aha moment” that will lead to “A prostate cancer cure”, you might do as I had to do and Google the word I had not heard of in the above figure, “chromothripsis“. Rather, the research leads to some very important insights that will doubtless contribute towards more effective therapy for 1000’s of patients eventually. By looking at the structural variants in the DNA that occurs outside of expressed genes, a much more complex picture of what drives castration resistant prostate cancer (CRPC) becomes evident. For example the androgen receptor (AR) is over-expressed in the majority of metastases and this study found a region of the “junk DNA” (non-coding for genes) that lies 66.94 million base pairs upstream of the AR that was amplified in 81% of the cases. This was 11% more common than the amplification of AR itself – an indication of how important the DNA controlling a gene like AR is, compared to the gene itself. So much for calling the DNA that doesn’t code for a protein “junk”!

A second example is the insight into patients who have alterations in a gene called CDK12 that may render them more sensitive to one of the “hottest” areas of cancer research, the use of checkpoint inhibitors of the PD-1 pathway I described in my last post.  This abnormality results in the cancer cells having an increased number of “neoantigens” (targets) for the immune system to attack as shown in this illustration from another recent exceptional paper.

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The ongoing research from the many scientific teams focused on prostate cancer is awe-inspiring when you consider the complexities involved in the two figures in this post alone. Even getting a complete picture from a single patient is impossible, given the genetic instability and the variable mutations found in different metastases. Remember, this team looked at the DNA from only one (or a few) of the many metastatic sites found in each patient. Other studies have shown lots of different mutations depending on which site is evaluated as I reviewed here.  In spite of all of this complexity, the ability to at least begin to understand what is going on “underneath the hood” is the way forward, and just as we can recognize Fords vs Chevys vs Toyotas, “brands” that emerge from such studies will lead to treatments that are more appropriate for certain classes of patients. As we have known for a very long time, the most common feature is the “gasoline” of testosterone, and how it fuels the amplified AR has remained an effective target for the newer drugs like abiraterone, enzalutamide, and apalutamide. Perhaps studies such as this one will lead to a way of kinking the hose upstream of the gasoline nozzle, or throwing sand (immunotherapy) into the engine itself. But… to admit that we will never understand it all (or design the “perfect human”) still seems an appropriate expression of humility to me.

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An Amateur Explanation of Immunotherapy


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For as long as I can remember, there has been lurking excitement regarding the possibility that our immune systems can find and destroy cancer cells. The history of well-documented spontaneous remissions goes back decades and is briefly reviewed here. I have personally never seen a spontaneous remission of cancer, although I have had patients who have done far better than anyone would have expected, suggesting that something must have slowed down their tumor progression.

In prostate cancer, one of the early hints that it might be possible to stimulate an immune attack on the disease came from the studies on Provenge (Sipuleucel-T). My colleagues and I placed several patients on the trials that led to approval of this “vaccine” by the FDA. These studies have continued to demonstrate improved survival of patients with metastatic disease who have failed hormone therapy, although the trials were all done before the availability of the newer ADT drugs abiraterone, enzalutamide, and apalutamide. On the other hand, in spite of the optimistic data we obtained in another vaccine trial on a product known as prostvac, the pivotal trial to prove efficacy failed. It is possible that the vaccine produced modest efficacy, but the signal was drowned out by treatment with the new ADT agents.

As anyone who watches the evening news or other TV-ad-saturated programs aimed at us seniors, other cancers – especially melanoma, lung, bladder, kidney and a few additional ones have been more “easily” treated with newer immune therapies known as check point inhibitors. The idea here is that our normal immune system has built in “braking systems”, the best studied and clinically utilized to date being the PD-1/PDL-1 mechanism. If we immunize you against, for example, measles – you want a vigorous immune response, but you don’t want your entire immune system to keep working on fighting measles. There are other threats it needs to be on guard against. Shutting down the T-cells that fight viruses and cancer involves the Programed Death receptor-1 on these T-cells with a specific protein, Programed Death receptor Ligand-1. Cancer cells can take advantage of initiating this same braking system by releasing their own PDL-1 that will kill the incoming tumor-fighting T-cell. This devious cancer mechanism to avoid our immune systems can be blocked by therapeutic antibodies directed against either the receptor or the PDL-1 ligand protein.

At the recent ASCO meeting, it was revealed that selected metastatic lung cancer patients who have an activated PD-1/PDL-1 braking system are now more effectively treated with pembrolizumab (Keytruda) than chemotherapy. It is emerging that the subgroup of patients who have tumors that are genetically highly unstable, (regardless of tumor type) with lots of mutations leading to abnormal proteins that can stimulate an immune response, may all benefit from PD-1/PDL-1 directed therapy. These patients, including prostate cancer patients can be identified by testing their tumors for microsatellite instability or mismatch repair deficiency. At a practical level, however, when and how to test prostate cancers for such biomarkers remains challenging. Last week at the ASCO annual meeting, Dr. De Bono from the UK reported results on treating patients with metastatic prostate cancer who had progressed on hormones and chemotherapy (docetaxel) with pembrolizumab. 17/163 patients had ≥30% shrinkage of their tumors, but overall results were disappointing with only 11% of patients having ≥50% decline in PSA. Testing for the presence of PDL-1 was not particularly predictive of which patient would benefit most. However, this way of treating prostate cancer will eventually lead to important progress in my opinion. Combining vaccines with the checkpoint inhibitors is currently being studied, and there are other checkpoint drugs and targets that are in development as well. Timing the checkpoint drugs with hormonal therapy or radiation therapy may also find optimal ways of stimulating an immune response. The field of immuno-oncology is an exciting new frontier and well worth keeping your eyes on.

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Of Prostates and Teslas


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If you thought this might be an article about how your urologist shops for his/her newest fancy car, you are mistaken (sadly…). Nikola Tesla was a fascinating inventor and ultimately “mad scientist” at the turn of the last century. Every time you plug your cuisinart into the wall to chop something up, you are the beneficiary of his contributions to the alternating current coming to your kitchen and the motor driving the chopper. My favorite story (because of the local connection) was his laboratory in Colorado Springs, where he attempted to develop a method of transmitting power without wires. By creating YUUUGE electromagnetic fields, he could make lots of electrical things happen at considerable distances, including knocking out the power station for the city. Here’s a quote from the Wikipedia article:

He produced artificial lightning, with discharges consisting of millions of volts and up to 135 feet (41 m) long.[11] Thunder from the released energy was heard 15 miles (24 km) away in Cripple Creek, Colorado. People walking along the street observed sparks jumping between their feet and the ground. Sparks sprang from water line taps when touched. Light bulbs within 100 feet (30 m) of the lab glowed even when turned off. Horses in a livery stable bolted from their stalls after receiving shocks through their metal shoes. Butterflies were electrified, swirling in circles with blue halos of St. Elmo’s fire around their wings.[12]

Of course, for purposes of this blog, the key thing is that the strength of magnetic fields was named after him. When you get an MRI of your prostate, brain, or anything else, you are put into a machine with a superconducting magnet that produces 1.5 or 3 “T” of strength. At the risk of being completely wrong and oversimplifying, what happens in the MRI machine is that a strong magnetic field temporarily lines up the hydrogen atoms in the water that is 70% of “you”, and when these atoms “relax” they give off radio signals that can be converted to images. Details and images are here. Early on, my colleagues and I were fascinated by the possibility of using MR to investigate the prostate gland and published an article (completely ignored – cited only 3 times, so must not have been that important…) showing changes in MR that occurred after testosterone administration to castrated rats.

Now there are complex MRI protocols to image the prostate using techniques I don’t fully understand (multiparametric imaging) that give us remarkable pictures of the prostate gland. Here is one:

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Prostate gland with red arrow indicating a suspicious lesion that could be biopsied or followed closely.

As with any radiologic imaging technique, the skill of the radiologist as well as the equipment being used determine the accuracy of the MRI to diagnose a cancer.

While most of us learned how to “read X-rays” in medical school, it is beyond most clinicians to read MRI’s of the prostate. Fortunately, the radiologists have developed a system that helps us think about “how abnormal” some area of the gland is, called PI-RADS.  This can be very useful in thinking about what area to concentrate on when biopsying a patient, or in trying to determine whether surgery or radiation therapy should be altered if there is concern that the cancer is outside of the gland. An interesting question that is still controversial is whether the MRI could replace repetitive biopsies in a man who has chosen active surveillance. Particularly when combined with molecular techniques (see my previous blog here) to characterize biopsies, it may be that Tesla will be helping to do more than get you from one place to another or run your electric shaver. (Rock on, Elon Musk) To me, that is a pretty interesting outcome from knocking out all of the lights in Colorado Springs!

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