Saturday, July 19, 2014

On MH17 and Air Travel


Air travel is close to our heart. It is a means to our dreams, and a means to reach our loved ones. It brings us to a vantage point we would otherwise never reach, and a soaring height only few before our generation could imagine.

This is Melbourne at night. It is the scenery I enjoy every fortnight as I travel between work and family. It is also the scenery that many on #MH17 would have enjoyed have they made the connection flight to Melbourne, and where the 100 AIDS researchers and activists would have convened to further their noble effort in curbing the AIDS epidemic.

Even though I fly quite often, every time the jet engines revs up on the runway, I still get the jitters. This is the juncture where the devout offers a prayer to the Gods. This is also the juncture where I take comfort in the air safety statistics, the rigour of aeronautical engineering, the excellent training of the air pilots, and the relentless work of the ground staff checking on the aircraft's structure every time it lands.

Much has been written about the fragility of life in light of recent events. Every time I fly my mother would say "be careful" - and I know by that she actually means "please don't be unlucky". It is pointless pointing out that air travel is the safest mode of travel, because we as passengers have zero control over its safety, and when things go wrong, they go horribly wrong. "You only live once", as the partygoers say.

Let us grieve with our fellow friends and families. Let us offer our condolences. Let this be a seed for us to seek peace, for us to engage in world events and do our parts. Let this be a trigger for us to be a better person to strangers around us. Our individual lives are ephemeral, but our love and our values outlive us, and on the larger scale, this is what really matters.

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Wednesday, July 09, 2014

Pretty Lucky Sports Spectator

I seem to have a knack for picking the right matches to stay up for.

Sporting history I stayed up to witness past midnight in recent years:

  • Zidane's headbutt in World Cup Final 2006
  • Federer vs Nadal "best match ever" Wimbledon Final 2008
  • Federer vs Djokovic "most epic final since 2008" Wimbledon Final 2014
  • Kyrgios vs Nadal "giant slaying" Wimbledon Quarter Final 2014
  • Brazil vs Germany "the worst slaughter in World Cup history" 2014
I think I am pretty lucky. 

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Wednesday, July 02, 2014

Doctors' Right to Dispense Medicine

I refer to the Dr Sng Kim Hock's letter to The Star on 27 June 2014 titled "Docs' right to dispense medicine". In the letter, Dr Sng (and Association of Specialists in Private Medical Practice, which he represents) is of the view that dispensing of medication is the sacred right of the physician.

The family practitioner must be appreciated and valued for their contribution to society, as they have for decades been providing primary care to the patients, screening the patients and hence ensuring that the general health of the community remains good.

The foundation of their practice includes the dispensing of medication, thus ensuring prompt symptomatic and curative care.

The presence of pharmacies nearby or next door should complement their service, but should by no means displace their role in early and urgent therapeutic intervention of illnesses as provided by the family doctor.

We cannot copy the practice of the developed western world, where there is a clear distinction and division between the roles of a doctor and a pharmacist.

No pharmacy in the West would continue to provide repeat medications or even offer consultation to the patient, to “save” costs, as is sometimes seen in this country.

For the above reasons, the role of the physician and doctor to provide consultation, care and treatment to the patient as a one-stop centre must be protected and continued for the present.
I am flabbergasted that Dr Sng actually believed that a doctor should dispense drugs because it's the sacred right, rather than because of the logistical limitation of our country. As a couple of academics have pointed out in a well-written response, there are a variety of reasons why the separation of role between doctors and pharmacists are beneficial and is something we should strive towards.

The elephant in the room, in my opinion, is the conflict of interest. When doctor prescribes a medication and derives financial benefits from the dispensing of the said medication, it is vulnerable to monetary incentives. Why would I dispense the generic rosuvastatin which is shown to be equally effective in ischaemic heart disease, when I know the rich patient in front of me can afford the Rolls Royce atorvastatin, which would keep my wallet and my pretty pharmaceutical rep happy?

One could argue that similar financially swayed practice may also be seen if dispensing is to be left to pharmacists. However, when the division of role is implemented, there is an additional chain on which government can regulate. For example, in Australia there is a government sponsored campaign for pharmacist to dispense pharmaceutically equivalent generic version of a drug when a patient is prescribed a branded medication.

I am similarly baffled by the fallacious statement in the penultimate paragraph. Is the author implying that doctors in Malaysia will repeat medication because they know the patient, while in Western countries patients have no access to repeat medications? Has he not heard of a "repeat prescription" which allows patients to a certain number of repeat medication? Besides, what is the reasoning about consultation being offered to save cost? Do Malaysian doctors do repeat consults and give discount simply because the patients are also obtaining their drugs in the same practice?

The logic is beyond me. I hope more pharmacy colleagues would stand up and stand for the division of role between two inter-connected but distinct healthcare specialties. In essence, this is only the fairest and safest option for our patients' welfare.

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Sunday, June 08, 2014

The Fault in Our Sobs

Today I watched The Fault in Our Stars which is an outstanding movie about two teenage people in love, who happen to have cancer. It is adapted from an eponymous book written by John Green who is one of my idols - a nerd with a passion for sharing knowledge and wisdom, who creates some of the most inspirational youtube educational videos out there.

After reading some glowing reviews online, I went to the cinema expecting a fully enjoyable experience with my wife. Unfortunately, my expectation fell way short - the movie itself is excellent, but the experience was not. It was probably a bit dumb of me to not have foreseen the general population of the movie audience of this movie.

High school girls.

For almost the entire movie, quite a number of these young souls were sobbing so loudly that I am constantly distracted from the movie itself. Obviously this being a tragic romance, most people would shed a tear or two in the cinema; but these few girls brought it to an entirely different level by crying louder than the characters in the movie itself. I was not even just unfortunate to be sitting close to them; they were sitting some three to four rows away from me.

In fact, they were still sobbing in the shopping centre after the movie.

I think there should be movie etiquette somewhere that says "thou shalt not impair fellow moviegoers' experience". In fact I am sure there already is, and the same principle is what underlies the banning of mobile phone, crunchy chips, and spoiling the plot. I would kindly argue that sobbing at 90 decibels should probably be one of them too.

---
SPOILER

Spoiled experience aside, I was quite pleasantly surprised by the relative accuracy of portrayal of illness, medicine and disease in general in this movie. As a hopeless fussy nerd, it really helps with keeping my annoyance at bay when I see an accurate portrayal of a tight fitting non-invasive ventilation mask for a girl in respiratory failure from worsening pulmonary effusion. Or a chest drain inserted to drain a pulmonary effusion (albeit being on the opposite side of what is shown on her X-Ray). And the delayed shortness of breath as she struggles to make up for the oxygen debt after climbing the stairs.

Tiny things like these show that these are done by people who have seen actual patients instead of just making it up, like most Hong Kong dramas do. They help make things real enough and allows you to start feeling empathy for the characters, instead of being constantly reminded of the artificiality of the movie. The fact that John Green drew his inspiration from his day as a student Chaplain in a children's hospital also helped. He's just such an awesome guy.

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Saturday, May 10, 2014

My Frank Two Cents - Now Public

Just a quick note to announce that seven years after its conception, I have now made public my previously "private" blog. It's accessible here.

It has not been updated for a pretty long time but I believe most of the content remains relevant today.

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Sunday, January 19, 2014

This 15-Year Old Did Not Transform Medicine

I recently came across this news article about Jack Andraka, a 15-year-old boy from Maryland who invented a test to detect pancreatic cancer in its early stages. Naturally this is HUGE. For those who are not familiar, pancreatic cancer is one of the worst cancers one could get. Due to its lack of symptoms (as it's seated deep inside the abdomen), it's usually diagnosed at a very late stage, and the majority of people do not survive for longer than one year.

This simple, fast and cheap blood test Jack Andraka invented promises to change all that altogether, creating an unprecedented revolution in medicine by causing the greatest improvement in cancer medicine we have ever seen. This test costs just 3 cents, nearly 100% accurate, and won him the grand prize in the prestigious Intel International Science and Engineering Fair. The test uses nanotechnology to detect mesothelin, a type of protein which is found in the blood when one has pancreatic cancer. His wish is that this test will become widely available on the shelves of the supermarket, and everyone could just pick it up and do this test during their free time, and no one will die from late stage pancreatic cancer any more.

It's very nice, except that it does not work.

First of all, I would like to congratulate this bright young man for achieving so much at such a young age, and has dipped his feet into the world of scientific research and made a name for himself. To have your name on a "cancer sensor inventor" as a 15-year-old boy is simply amazing.

However, unfortunately that's where the achievement ends.

As a medical doctor I feel compelled to debunk the hype: This invention will unfortunately NOT save lives, and in fact I suspect if it were to be introduced as a 5-cent dipstick available in your local supermarket (which WILL NOT happen as you will see below), it may actually end up doing more harm than good to people's health.

It may be a difficult concept to explain but I hope you bear with me as I go through the reasoning.

I would begin by how making diagnosis works. It is often mistakenly thought that diagnosing a disease in the modern era is as easy as finding the correct protein in the blood, and BAM you have this disease. It's almost like if you find a fingerprint then BAM there has to be matching, unique person behind that fingerprint. However, the majority of medical diagnoses are simply not made this way.

I would use the pregnancy test as an example. We all know that urine or blood pregnancy tests are pretty accurate these days - it detects a hormone called βHCG which is secreted during pregnancy. So, if you find βHCG in urine or blood, then you are pregnant, right? WRONG. While the vast majority of high βHCG is due to pregnancy, sometimes it could also be due to sinister causes called gestational trophoblastic diseases which are a type of tumour in the genital organs. But in practice, if you missed your period and you are tested positive, then you would be told "you are pregnant" unless the doctor has deep suspicion that something amiss is going on.

This is because
  1. There are FAR MORE pregnant people than people with this tumour 
  2. The fact that you missed your period makes pregnancy even more likely.
βHCG is useful because:
  1. When it's level is very close to zero, then you can't be pregnant (It has good negative predictive value
  2. In pregnant people the level is ALWAYS elevated. (It is sensitive)
  3. When it's elevated, 99% of the time it's gonna be due to pregnancy (the other 1% being the gestational trophoblastic disease) (It is highly specific)
  4. When it's used, it enables good outcome (you know you are pregnant hence you commence antenatal care etc)
While these 4 conditions, especially the last, may seem trivial, they are THE criteria that any diagnostic test have to meet prior to being practical. If someone comes along and develop a 5-cent new pregnancy test, they will either have to meet these criteria, or being dumped despite being only 5 cents.

That's for diagnostic test. Moving on to screening test. Wouldn't it be nice if we find a test for early stages of various cancers, so that all we need to do is to wake up everyday and dip a few drops of blood, and we would know that we have (or not have) cancer? Yes it would be nice, but unfortunately medicine is hard and nothing like this exists, and no, Jack Andraka's dipstick is not the elusive magic test.

I would use PSA as an example. PSA (Prostate-Specific Antigen), as the name suggests, is a protein quite specific to the prostate, and is elevated in prostatic cancer. We used to do PSA screening quite commonly to detect early prostate cancer (but it's no longer recommended but that's a long story on its own). The problem with PSA, as with many other types of cancer blood tests, are that they are not specific and often not sensitive enough. In PSA's case, there are many other conditions which also increase its level (namely large prostate, severe infection etc). And last but not least, because prostate cancer is such a slow growing tumour, it's been found that even after using PSA and detecting some earlier cases, the mortality rate (chance of dying) is THE SAME whether or not you test everyone for  PSA. Hence population-wide prostate cancer screening is no longer recommended.

Moving on to mesothelin and pancreatic cancer. 

For the scholarly minded, this is THE article that shows why mesothelin is useless as a pancreatic cancer screening marker: 


Jack Andraka is right in pointing out that mesothelin is almost always present in patients with pancreatic cancer. However, mesothelin is ALSO present in ovarian and pleural cancer, AND in normal healthy people. The range of mesothelin level amongst pancreatic cancer sufferers overlaps greatly with the level amongst normal population. Even though Jack claims this to be 100% sensitive, it only means that it will detect a particular level of mesothelin 100% of the time. It still does not meet these criteria:

1. Does mesothelin differentiate between different cancers? No as it's also present in ovarian and pleural cancer. 

2. Does mesothelin differentiate between disease and health? No, when you are "positive" for mesothelin you may very well be healthy. 

In other words, if you bought this test and is tested positive, you could either have pancreatic cancer, other pancreatic conditions, ovarian cancer, pleural cancer, or have nothing at all. Not that useful isn't it? 

At this juncture, some people might claim, even if some healthy people mistakenly test positive in this test, they could always just do more tests and find out that they don't have disease - isn't that better than the alternative, having pancreatic cancer and not knowing it? The answer is NO. As pancreatic cancer is such a rare disease, you will have far less disease detection rate (true positive) than false positives. The thousands and thousands of people who had false positive results will now have to go through more tests (CT scans, biopsies etc), and all these tests actually do harm if you are healthy (CT increases your risk of cancer, biopsies are invasive procedures and put you at risk of infection and bleeding). So in the end, having such a test, despite costing only 3 cents, will end up putting a lot more healthy people at risk of complications of over-investigation than saving a few lives from its actual detections. 

To sum it up: Yes this man has a bright future, but he's not a cancer saviour, and we still have a long road ahead in our battle with cancer. He is not the genius kid who managed to discover something that millions of scientists in thousands of universities have overlooked in decades of cancer research. Unfortunately there has been a huge media circus surrounding his invention, most of which were more focused on perpetuating the "prodigy cancer saviour" feel-good story without getting an established scientist to put things into context. The whole media circus has planted a distorted perception on cancer research, and could end up instilling distrust amongst public in proper scientists and researchers. In the comment section of the aforementioned news article, the top comment is about how such an invention (like the many dozens of "cancer cures" invented each month) will never see the light of the day because pharmaceutical companies need to keep making money from cancer treatment drugs rather than saving people's life with cheap, easy and effective inventions like this. It insults the efforts of millions of scientists in labs everywhere, who toil away in their often frustrating and mundane efforts day in day out, without the benefit of being glorified in the media as a cancer saviour.

When something sounds too good to be true, often it's because it is too good to be true.

Footnote: This article by Forbes Science is one of the rare media articles which summarised the hype surrounding Jack Andraka instead of joining the media circus of how we have found the young saviour which will save millions of lives, before he even published a single journal article on the invention.

Footnote 2: Another article with a LOT more details about doubts on Jack Andraka's invention and personal motives, though it is a lot more sensational and may sound more personal. 

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Monday, April 30, 2012

6 ÷ 2 (1+2) = ?


Personal Note: It's been more than a year since I last wrote on this blog, and let's just begin by stating that, YES I AM ALIVE. It's been an interesting fifteen months, where I transformed from a sheepish new intern with a quavering voice while saying "Hi it's Yang one of the... doctors" to a more confident doctor who is still humbled everyday by the nature of the amazing job. Oh and I also got engaged in the process. :)


You have seen it before. Yes, this is a reincarnation of the infamous 48/2(9+3). 

If you have not seen it, take a few seconds to work out the answer. In fact, even if you have seen it, try to solve the equation again in your head. 

Now that you have got it, let's check the answer. The "correct" answers are 288 and 9 respectively. Now, I will explain the quotation marks in a second.

When the original 48/2(9+3) question was released into the World Wide Web, it cooked up a storm as people hotly debated whether the answer should be 288 or 2. The "correct" answer is derived based on the strict interpretation of the "BODMAS" rule, which stands for Brackets, Order (Exponent), Division and Multiplication, Addition and Subtraction. Based on this rule, the operation should be
48 / 2 (9+3)
= 48 / 2 (12)
= 24 (12)
= 288
On the other hand, the proponent of the answer of 2 works it out this way:
48 / 2 (9+3)
= 48 / 2 (12)
= 48 / 24
= 2
Evidences have been thrown about in support of each argument. WolframAlpha and Google's default calculators both give the "correct" answer of 288. [1][2] However, different scientific calculators give either versions of the answer depending on brands and models. 


So which answer do I think is correct? I think the first one is technically correct, but the second one is not wrong either. The biggest mistake is in fact the person who wrote such an ambiguous expression in the first place. 

Before we go any further, let me introduce you to this video by vihart (starting from 2:32)



"I would like some juice or water with ice - do you mean you want either juice with no ice or water with ice, or do you mean you want either juice with ice, or water with ice?"

Essentially this argument is pointless. It detracts from the true spirit of mathematics which is to derive and discern fascinating pattern and relationship in nature based on a set of axioms. All this argument does is to delve into syntax which evolved arbitrarily in the evolution of mathematical notation  - it has NOTHING to do with whether the maths is right or wrong.

The conflict comes from the fact that "BODMAS" is taught in primary schools when we still use the sign "X" to mean multiplication, and the sign ÷ to mean division, and if you wrote out this equation 6 ÷ 2 X (1 + 2), then no one would have gotten it "wrong" based on the simple BODMAS rule. 

However, as we progress in our mathematical education, X is replaced by simply having two entities written next to each other, and ÷ is replaced by writing out the expression as a fraction. Because of this, when first presented with this writing of 6 ÷ 2(1+2) [also note the very intentionally misleading spacing in the original photo], the intuition in anyone who have become familiar with the advanced mathematics notation would automatically translate this into:
especially due to our natural instinct of grouping the multiplication together when a bracket is involved. So this is where the mistake came from. 

Just throwing a last question here to illustrate my point: what is 1/2x? Is it half of x, or is it the inverse of 2x? The answer is, it is neither, it's just a poorly constructed mathematical expression, and the debate on semantics is just a waste of time.

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