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Cancer Research 101: 1/8/12 - 1/15/12

Saturday, January 14, 2012

The Big Question…

Let's continue the numbers theme from the last post just a little bit further.

In my travels, I think that the two most frequently asked questions have been, "Are we really making any progress?" and "Are we ever going to find a cure for cancer?"

My answer to the second question, which is really the main question on most everyone's mind, is as swift as it is equivocal: "Yes… and No".

The reason for my hedging is not because I'm afraid of commitment :-) Rather, it's because the question "Are we going to ever find a cure for cancer?" is the wrong question to ask. The correct question is "Are we ever going to find cureS for cancerS?".This may seem a little bit like splitting hairs, but I assure you that these questions are vastly different.

One must keep in mind that the word "cancer" is an umbrella term, not the definition of a specific disease. If you think of “infectious diseases", there are undoubtedly thousands of types of infections, all of them different. They can range in severity from the mild but annoying common cold all the way through to an infection with a deadly agent such as the Ebola virus. We would never confuse the two of those, yet we would consider both of those broadly to be "infections" of one sort or the other. And so it is with cancers.

By current estimates, there are perhaps as many as 200 to 300 different cancers. While they all share some common characteristics, some of them are as different as night and day. A tiny solid tumour in your thyroid for example may bear very little resemblance to a leukemia that affects all the white blood cells circulating through your bloodstream. To think of these two very different types of cancer as being the same thing is equivalent to thinking that two different types of infection are the same thing.

Thus, it is my sad duty to have to say that I do not believe we are ever going to find A cure for cancer. There will not be, in my opinion, a single "magic bullet" that we can ever hail as “the” cure.

But one should not despair. Just because we will not find a single magic bullet cure for "cancer", doesn’t mean that we can’t cure many cancers right now. Depending on how you define ‘cure’ (most commonly used statistic is 5-year survival, although less commonly 10-year survival is sometimes quoted), I contend that we can cure many cancers right now.

Consider the table below, for example. It is taken from the latest version of the Canadian Cancer Society's annual publication: Canadian Cancer Statistics 2011, published by the Canadian Cancer Society's Steering Committee on Cancer Statistics; Toronto, ON, 2011. In this table, at the top, you can see the five-year relative survival rates for someone newly diagnosed with any cancer. This is the 62% survival rate I referred to in the previous post.

But on this table you can also see some very high five-year survival rates for a number of cancers, survival rates that far exceed the average. Thyroid cancer, with its survival rate of approximately 98% is what I consider to be a very curable cancer. Not shown on the table is testicular cancer which boasts a similar survival rate of approximately 95%. It may surprise you to see prostate cancer on the list with a survival rate of approximately 95%. This attests to the fact that most men will die WITH prostate cancer as opposed to dying FROM prostate cancer.

Look also at breast cancer on the list. I would be the last person to stand up and claim that breast cancer is now a totally “curable" disease. But consider the fact that any woman diagnosed today with breast cancer, at any stage, has approximately an 88% probability of surviving that diagnosis. And if the cancer is caught early, at Stage I, where the tumour has not left the breast, that survival rate climbs to something on the order of 96 or 97%.

Obviously, with both breast and prostate cancers, even very high 5-year survival rates do not tell the whole story. Although the percentage of patients who do not currently survive is getting smaller and smaller, the absolute number still represents a lot of individuals. The last thing I wish to do therefore is to trivialize in any way a diagnosis of breast cancer or prostate cancer but I do want to put it into perspective: both of these cancers have very, very high survival rates today, largely due to advances in research, early detection and treatment.

Even colorectal cancer, the cancer that killed my own father, deserves mention. You will see on the table that the overall five-year survival from colorectal cancer is only about 63%. But again that is the average and takes in all colorectal cancers diagnosed at any stage. Colorectal cancer when detected early is, for all intents and purposes, a totally curable disease. The number of people dying from colorectal cancer would be hugely reduced if more people would avail themselves of current screening methodologies, and if research can help us develop even better early detection screens.

Of course all the news isn't as good. One only has to look at one or two of the cancers at the bottom of the list, notably lung cancer and pancreatic cancer to show how much farther we have to go to deal with these very deadly forms of cancer. These are but 2 kinds of cancer where research has a great opportunity to make significant new impacts over the coming years.

Will we continue to find ways to cure more and more cancers? Without any doubt in my mind whatsoever! Is it possible that we may never find cures for some cancers? I think that is not only possible but perhaps even likely.

My own belief is that with continued research and better treatments we will indeed cure more and more cancers, but those that we cannot cure outright we will increasingly transform from diseases that one dies from into diseases that one lives with...

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By the Numbers…

I confess: I'm not usually one who is very fond of cancer statistics. I find that statistics can be rather dry and, taken the wrong way, can often be quite misleading. I prefer to tell stories, create analogies and metaphors, and to try and give examples of where cancer research has really impacted the lives of real people across our country and beyond our borders.

That said, sometimes showing a few numbers can be the right thing to do.

People still widely believe that cancer is an inevitable death sentence. This is simply not true. Consider the improvement in"survival rates" since the 1940’s and you will see what I mean. In the 1940’s, anyone diagnosed with cancer (that is, any cancer and at any stage) indeed had only about a 25% chance, on average, of surviving that diagnosis. By the 1960’s that number was probably up to about 33%. I wonder if you appreciate that today, thanks largely to advances in cancer research, the average five-year survival of someone newly diagnosed with cancer (again, that is any cancer at any stage) is about 62% and climbing. That means that nearly 2/3 of all individuals diagnosed with cancer today will survive that diagnosis.Obviously, we still have a very long way to go before we achieve the ultimate success of everyone surviving a cancer diagnosis, but one needs to appreciate that the numbers keep getting better and better. We are creating more and more survivors, and that is something indeed to celebrate!

In subsequent posts, I will explore some further statistics behind individual cancers and talk about the idea of "curing"cancers. I will also post about the issue of cancer “survivorship”, because it is not enough to extend the quantity of one's life, one has to look very importantly at the quality of that life as well.

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Thursday, January 12, 2012

Picking The Lock…

Most everyone has heard the old adage that the three most important things in real estate are "location, location, location".  If you were to use a similar approach for cancer therapeutics it might be "specificity, specificity, specificity".  To my mind, 'specificity' may be the single most important attribute for any cancer therapeutic to be maximally effective, and therefore the search for absolute specificity is in many ways the Holy Grail of cancer research.

Why do I say this?  To start with, there is a myth in the public's mind that it is difficult to kill cancer cells.  Frankly, this is nonsense.  Generally speaking, it is very easy to kill cancer cells.  What is difficult is killing ONLY cancer cells and leaving normal cells unscathed. This is where, by and large, cancer treatments of the past have failed us. 

But aren’t anti-cancer drugs, by their very name and nature anti-“cancer” drugs? There is where a second misconception enters the fray: that most chemotherapeutic agents have been specific anticancer drugs.  Actually, for the most part, most of the “classical" chemotherapy agents have in fact been drugs that interfere with cell division as opposed to being anticancer drugs per se. In fact, most of these drugs of the last generation target rapidly dividing cells, not necessarily only cancer cells. 

While it is very true that most cancers are comprised of rapidly growing cells, unfortunately they are not the only cells in the body that divide rapidly. For example, for those unlike myself were not follicularly challenged <smile>, your hair cells divide rapidly and replenish quickly. The cells in your digestive system and your gut are being replaced at a very fast pace.  And the cells that populate your blood system are also dividing quickly and on a constant basis to provide a (usually) never-ending supply of blood cells of all sorts.

By now, you can probably see where I'm going with this.  What are the major side effects at we usually associate with chemotherapy?  Your hair falls out, you get sick to your stomach, and more often than not you get anemic.  That's because the normally rapidly-dividing cells in your hair, your gut and your bloodstream are also under attack. The chemotherapeutic agents interfere with their rapid division in much the same ways they interfere with the rapid cell division of cancer cells.

So the trick is to discover and develop treatments that recognize truly unique properties of cancer cells, i.e., properties that are not shared with non-cancer cells. Simply targeting rapidly dividing cells is no longer be adequate (not that it ever was...).  We need to discover better signposts that define and identify cancer cells as opposed to normal cells.  We need to find new ways to make cancer cells stand out from the crowd, ways that make cancer cells scream out at us "I am the cancer cell.  Don't waste your time with those other normal cells. Take me!"
Look at the two accompanying pictures: I like to think of this as the old barn door analogy.  No longer is it acceptable to do a scatter-shot at the side of the barn in the hopes of hitting the barn door.  Now we want to go in and pick the lock...

I doubt that very many of my cancer research colleagues would appreciate being called the next generation of lock-pickers, but in one very real sense that's exactly what they are! The more and more specific, the more and more targeted and the more and more selective we can make our future cancer therapeutics, the better will be the treatment, the better will be the outcome for patients and the better will be the quality of life for patients during and after treatment.

This notion of targeting and specificity will be a constant thread throughout many of the posts to follow. You've all heard by now, I am sure, of the notion of "personalized medicine" or a related term "precision medicine".  This is a very important part of the whole notion of attaining maximum specificity in the treatment of cancers of all types.

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Slash and Burn and Poison????

In my travels across the country over the past 20 years or so, one of the most common questions I got was "where's the progress?"  Or "are we really making any progress?".  After all, people often said to me "it's 50 years later and were still slashing and burning and poisoning", meaning that we are still using surgery, radiation and chemotherapy as the basic modalities of our therapeutic armamentarium.

Since I am not a physician, and therefore do not treat patients directly, I rarely talked to people about absolute specifics of various therapeutics and treatments. However when confronted with the "slashing, burning and poisoning" comment here is the answer that I often used.

Take a look at the two photographs that I have included in this post.  In the photos you will see two cars.  One of them is the 1908 model T Ford - you know the one that Henry Ford said that "you can have in any colour you want - as long as it's black" :). The other is a somewhat more modern version of a Ford GT sports car.  (Disclaimer: I do not own a Ford, and do not have any interest in Ford, but am merely using these pictures for the purposes of illustration.)

Look at the two pictures and ask yourself, "where's the progress?".  No one would have the slightest hesitation in noting the incredible progress that has been made since the very first automobiles were introduced compared to the state of the art today.

And yet, both of these cars still use a version of an internal combustion engine, they both still roll on four rubber tires, and they both still have a mechanical steering device called a steering wheel by which you navigate them.

Where's the progress indeed?

The point is, of course, that just because both cars have engines built upon the same fundamentals, or rubber tires or round steering wheels, we should not be fooled, even for one millisecond, into thinking that there has been no progress. 

So it is with cancer therapeutics.  Just because we are still using surgery, radiation therapy and chemotherapy does not in any way mean that we're still doing things the same way we did 20 or 30 years ago – or for that matter even 5 or 10 years ago!  The advances that research has given us in surgical and radiation techniques are nothing short of remarkable, as we develop and employ more and more precision including laser-guided and computer-guided enhancements.

Research means that chemotherapy of today does not, and certainly chemotherapy of the future will not, resemble the chemotherapy that one had to endure in years past, as we develop more and more selective and more and more targeted therapeutics that attack the cancer cells and leave normal cells alone.

In subsequent posts, I will give you some examples of how we are getting more and more selective and therefore more and more effective in our treatments.  Research has led the way for us to use surgery radiation and chemotherapy in brand-new ways with much better effects and far fewer side effects.

The days of "slashing and burning and poisoning" are done…

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