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Tuesday, September 17, 2013

Free Prostate Screening! What's the catch?

I just got an email from a hospital where I sometimes practice with a picture of two aging but clearly active and vital men standing on a beach with the words "Free Prostate Cancer Screening" printed below in an attractive font. The hospital is sponsoring the screening, along with the urology clinic affiliated with the hospital. The advertisement gives guidelines for who should avail themselves of this service, including men as young as 35 years old if there is a family history of prostate cancer and otherwise 55 and older, with no maximum age.

The prostate is a walnut shaped gland that surrounds the urethra, in front of the rectum and just prior to the penis. It produces prostatic fluid which helps carry sperm to wherever they eventually end up. Prostate cancer screening, that is checking a man's prostate cancer via a rectal exam and also performing a blood test for PSA (Prostate Specific Antigen) has been of questionable utility for decades, and finally last year the US Preventive Services Task Force came out with their strongest statement ever, saying they recommended against prostate cancer screening. In prior recommendations they had questioned the utility of screening men at any age and had recommended that men over the age of 75 not be screened. Evidence piled up, however, showing that prostate cancer was significantly overdiagnosed, with many men being diagnosed and treated for prostate cancers which would never have caused them any harm if left undetected, and that the screening process itself, with biopsies and anxiety inducing repeated tests resulted in more harm than any help that would come of early detection. The members of the USPSTF, 16 nationally recognized MD and PhD volunteers who specialize in preventive medicine and public health, decided on this basis to recommend categorically against prostate cancer screening.

How is it possible that early diagnosis of cancer is bad? Cancer cells come and go in our bodies all the time. Some of them stay and produce tiny tumors that never cause us harm, others are eliminated by the immune system and by the normal processes of cell aging and death. Only some cancers become evil and endanger or kill us. If we detect the ones that would have caused us no harm, we then get treatment which is painful and harmful, expensive and dangerous. People die of over zealously treated cancers. Some particularly aggressive cancers, if detected early, will still kill us, but we will spend more of our lives having surgeries and chemotherapy than we would have if we had waited until they caused symptoms. Some cancers, of course, can be caught and eradicated at just the right time and finding these cancers can save our lives. Certain cancers are more likely to be cured when caught early than other ones. Colon cancer is frequently curable if caught early and fatal if allowed to spread. Some breast cancers are that way. Prostate cancer is extremely common as men age, and early autopsy studies concluded that if a man lived to be 100, he would have a nearly 100% chance of having prostate cancer if one were to check his prostate after he died of something else. A large proportion of men in their 70s and 80s have cancer cells and small tumors in their prostates, but have no symptoms and never will. People do die of prostate cancer, but detecting it early does not seem to make much difference in outcomes, at least not enough difference to outweigh the harms of screening. Prostate biopsy, which involves taking several needle cores of prostate tissue through the rectum, can cause persistent aching and blood in the urine, and sometimes detects cancer. Treatment of early prostate cancer involves removing the prostate via surgery or destroying it with radiation. Common side effects of these treatments include inability to control urination, diarrhea, sometimes bloody and uncontrollable, and inability to have an erection. These conditions don't actually kill a man, but they do significantly reduce his ability to vigorously engage in many important aspects of life.

This information is not a secret. For a time, the recommendation not to screen for prostate cancer was quite controversial. The American Urological Association, the professional organization of the doctors who biopsy prostates and operate on prostate cancers, did continue to recommend regular rectal exams and PSA testing until the last year or so, when they joined the American Cancer Society in recommending against screening before the age of 40 and after the age of 70, or for men with a life expectancy of less than 10-15 years. For the rest, they recommended screening only after discussing the risks and benefits of doing so with a doctor, with a shared decision making approach involving both science and the patient's preferences.

I thought perhaps this email I got was an artifact of an earlier age, and that this hospital had somehow failed to hear the news that screening all comers age 35 and above is a bad idea. Then I opened my local paper and found that one of our local hospitals was sponsoring a free prostate screening day with our local urologist. I googled Free Prosate Screening and came up with over 12 million results, some of which were recommendations against screening, but most were advertisements for free screenings, rectal exams and PSA testing.

Perhaps the urologists are not just doing a rectal exam and a blood test, but are dutifully discussing the risks and benefits of screening and engaging in shared decision making. But I doubt it. This subject takes a long time to discuss and shared decision making requires that the doctor explore the patient's expectations and values. Free screening clinics usually have lots of people and essentially no time for discussion. Perhaps symptom free 80 year olds would be turned away, but I can't really picture that. Instead I picture a waiting room full of apprehensive guys, many without access to a doctor willing to discuss preventive care with them, being hurried through a brief encounter with a doctor, a quick blood draw and then being handed a few possibly informative booklets which they will most likely never read.

Evaluating for prostate cancer is not a terrible idea if a patient has symptoms that might go along with prostate cancer, things like fatigue and bone pain and sometimes difficulty urinating or blood in the urine. This is not considered screening. This is a well thought out exam to help diagnose a disturbing symptom.

But what if a man just wants to know if he has prostate cancer, and then discuss the options of treating it or watching it with his doctor? Wouldn't PSA and rectal exam tests be useful for that? Such a can of worms. It is difficult for many men to be comfortable knowing that they have a cancer and not do anything about it. I have had patients who were at peace with this approach, but they were few. In America it is dramatic and somewhat embarrassing to admit to having cancer, but keeping it a secret is difficult too, especially from well meaning family. Also, having a normal PSA and rectal exam does not mean that a man is free of prostate cancer. Using a cutoff of a PSA of 4, about 15% of men screened with these tests had prostate cancer when biopsies were performed, in a study published in 2004. It is likely more cases would have been found had they used more modern biopsy techniques which sample 8-12 sites rather than the 6 samples taken by old protocols. "Normal" levels of PSA were adjusted down after this, labeling more healthy patients as abnormal.

So, bottom line, free prostate cancer screening is not free. PSA testing and rectal exams are not good ways to detect prostate cancers that would cause harm and could be cured by early treatment. Followup PSA testing may or may not help to detect more aggressive cancers but may not be paid for by insurance since PSA testing is deemed not to be very accurate. Prostate cancer is a bad disease, in many cases, and we need to continue to look for ways to detect the cancers that can be cured and effectively treat the ones that cause symptoms. But this does not involve foisting outdated screening routines on an unsuspecting public.

Tuesday, September 10, 2013

What is "overdiagnosis"?

I got an invitation in my e-mail a couple of days ago for a dinner presentation to the Central Oregon Medical Society given by H. Gilbert Welch M.D. on the subject of overdiagnosis. I was intrigued. A little less than a year ago Dr. Welch, an internist and professor at Dartmouth Medical School and Archie Bleyer M.D., a former pediatric oncologist and now a research professor at Oregon Health and Sciences University wrote a controversial article presenting compelling evidence that regular mammograms lead to death and disability related to aggressive treatment in many of the patients who were diagnosed with breast cancer but that it did not significantly improve survival.

Dr. Welch has been studying overdiagnosis for a couple of decades and has written two books, Should I Be Tested For Cancer-maybe not and here's why and Overdiagnosed: making people sick in the pursuit of health. I have peeked at the second one and found it to be well written, with a non-physician audience intended.

Overdiagnosis is defined as detecting disease in patients without symptoms which, if undetected and untreated, would lead to no harm. This is not a good thing. People who find that they have a disease often use more resources, get more testing and treatment with associated costs and side effects, and feel worse about their health. In the small picture, this is caused by increasingly sensitive screening tests, more strict definitions of normal and increased use of imaging procedures which see things we weren't even looking for. It has been pretty well established for breast cancer screening and for thyroid imaging which detect low level cancers which probably would never progress and for prostate cancer for which, in most cases, the treatment is worse than the disease, and the disease is extremely common. It also appears to be true for kidney failure, which has been diagnosed more and more commonly in elderly people despite the fact that we know their kidney function normally declines with age. Overdiagnosis occurs when we remove colon polyps which had no malignant potential during excessively frequent colonoscopies and when we screen ancient and dying people for cancers which would never contribute to their inevitable demise.

Overdiagnosis is estimated to result in many many billions of dollars of excess healthcare spending.

In the big picture, overdiagnosis is caused by the economics of our medical system: defining more people as sick increases use of medical care which keeps doctors and staff and the many industries that serve us and our patients in business. The patients who are overdiagnosed are also not very sick, or not sick at all, so they are easier to treat, mostly. It's a win/win situation. Except that it isn't.

Reducing our thresholds for defining disease is not entirely a bad thing, though. We have gradually reduced the blood sugar at which we diagnose a patient with diabetes. It turns out that slightly elevated blood sugars are nearly as predictive of bad outcomes as higher blood sugars. It has been my experience, as well, that patients who are told they have diabetes often immediately take seriously their needs for lifestyle changes, so they begin eating more healthily, exercising and losing weight which is undeniably good for them.

September 10-12, 2013 is the first ever conference on overdiagnosis at Dartmouth University, in which there will be talks about the extent of the problem and then discussion of ways to roll back excesses. Already there has been a conference on Selling Sickness which involved activists of many descriptions who came up with some resolutions to reduce "disease mongering". These include improving research to determine what tests and treatments are actually effective and separating funding for this from parties whose economic interests would benefit from positive results. The American College of Physicians and many specialty organizations have gotten behind the "Choosing Wisely" campaign which targets tests, procedures and treatments which are without proven benefit, though they may be widely practiced.

When we, as doctors, think about it, we don't want to be doing things that are of no particular benefit to our patients, even if it does give us job security. It makes us feel that our jobs are meaningless and it puts us at odds with the people we treat. We have been expanding our scope this way for so long, though, that it takes awhile to change gears, and communication and education has to be excellent in order that we come to consensus. Many of us think we will be sued if somebody develops a condition that we could have screened for, even if that screening rationally would not have made a difference in their outcome. We need good solid support for curtailing our excesses.

Central Oregon is a long way away from where I am, a good 7 plus hour drive, and the talk is only a couple of hours long, so I think I'll just read his book and read the articles that come out of the Dartmouth conference. If doctors who are well respected put their energy into this effort, good will come of it. I'm proud of us for trying.

Monday, September 9, 2013

Water and hand sanitization: some thoughts about technology and hygiene and how not to get sick or make other people sick.

This summer has been full of adventures in and around water, alongside people with and without disease caused by infectious intestinal organisms. It's been lots of fun, and I dearly yearned not to be slowed down by explosive vomiting and diarrhea. Because of this intense yearning not to feel like crap, I have been doing lots of studying and thinking about both hand hygiene and water purification and have been experimenting with various techniques and technologies.

Most infectious ills of the gut are transmitted by the fecal-oral route. The bacterium, parasite, virus or other unspecified microorganism must make its way from the feces (or sometimes vomit) of the infected person to the mouth of the new host to be ingested, thence to infect and cause disease. For many conditions it does not take many organisms to cause infection, and some of the causative entities can survive outside of a host in pretty unfriendly environments for various amounts of time (up to around 2 weeks for norovirus, for instance.) After having a bowel movement, the hands are the most adventurous parts of the body, in terms of making contact with other people, and so cleaning the hands is the most vital part of preventing person to person transmission. Water contamination with feces is very common, either from washing or directly depositing the intestinal contents in a place where they can be transmitted by rain or other mechanical means to a water source, or by animals who carry the pathogenic organisms pooping wherever the mood hits them. Thus purification of water is key to preventing the spread of infectious gastroenteritis.

In hospitals hand hygiene is often a matter of life and death. In the years before Ignaz Semmelweis instituted hand sanitization with a cholorinated lime solution in his maternity hospital in Vienna in 1944, death by puerperal fever (infection of the uterus at childbirth) was common. Despite dramatic reduction in deaths due to hand hygiene it has been a slow process getting physicians to clean their hands between patients. With the increase in multi-drug resistant infections and the increase in use of drugs which suppress the immune system in the treatment of cancer and autoimmune diseases, hand hygiene has become even more important as a way to keep the most difficult organisms to treat from finding new hosts in hospitals. Much research has been done to evaluate the practical and theoretical aspects of various ways to clean our hands.

The big controversy with hand hygiene has been between using alcohol based hand rubs and actual hand washing with soap and water. In the early 2000's various articles came out showing that a gel made of a high concentration of alcohol could successfully kill the majority of pathogenic bacteria without requiring that a person actually find water and wash their hands. This was game changing and resulted in the explosion of new products and the installation of hundreds of thousands of hand sanitizer dispensers in hospitals and other public places. To reap full benefits with these products, the amount of sanitizer must be sufficient to keep the hands wet for 30 seconds. Humans are prone to false economies and so many people will use just a little dab, which is close to useless, and has reduced the practical effectiveness of these things. It also became clear that there were certain organisms which were quite resistant to alcohol, and these were clinically very important. Clostridium difficile, the scourge of the antibiotic treated patient and a common hospital acquired infection is transmitted via spores which are quite alcohol resistant. Hand washing is much more effective for these and chlorhexidine is by far the most effective commonly available soap. In practice, use of hand sanitizer is much inferior to hand washing in nursing home settings in the control of outbreaks of norovirus, also known as the cruise ship virus. This may be because of inadequate use, but norovirus is also known to be resistant to these products. Soap and water handwashing, however, is also prone to failure because people don't spend enough time doing it. Twenty to 30 seconds of handwashing is necessary to remove the majority of microorganisms from the hands, and wiping them with paper towels appears also to be important.  Recently non-alcohol based rubs have come out, based on either benzalkonium chloride or benzethonium chloride, which are longer lasting and have a broader spectrum of bacterial killing. These will probably replace the alcohol based products. I am not terribly concerned about the impact on our overall biome with these products since the rest of the skin surface is unaffected and the hands do eventually get recolonized as we touch our arms and faces in normal everyday life. The chemical benzalkonium chloride has been around forever as an antiseptic and so safety is probably not an issue, but I am not totally sure about benzethonium chloride.

While using alcohol based hand sanitizer at a camp with people of various propensities and sensitivities, I was struck by the incredibly strong smell that persisted and so washed my hands after using it. I then realized the totally obvious practical point that it need not be an either/or proposition regarding hand hygiene. When I am not sure which microorganism I am trying to avoid transmitting, I should wash my hands and use hand sanitizer. It just isn't that difficult. With the alcohol based sanitizers, I should use them first, then wash. With the longer lasting chemical rubs, it would probably be best to use them second. In a water limited setting, like in developing countries, alcohol based sanitizers are clearly superior (see this study) to washing with water, even if the hands are visibly soiled, when they are actually available.

The biggest issue in any situation where these things are necessary is instilling discipline: people are just not very good about washing their hands, especially doctor people.  It would be easier if they could really see the impact of not doing it, which is often huge. It would also be easier if it was, in fact, easier, and I just ran into a gadget that fits that description at a barbecue shop in Bend, Oregon. A company called Meritech makes a hand washing machine that removes 99+% of bacteria from the hands in 12 seconds using an automatic dispenser of water and an antibacterial soap. It was strange to find one in this restaurant, but the owner told me she just thought it was an excellent idea. It cost her around $5000, and it was really fun to use. It felt like a hand massage and eliminated the issue of re-exposing the hands to bacteria when turning off the faucet. If they put these in hospital rooms, I think they would be a big hit.

But on to water purification. My first trip to Haiti was blessedly without intestinal impact. The next one, though, ended very poorly. I developed a fever, nausea, diarrhea then constipation and liver swelling. I couldn't eat for a month without becoming nauseated. I recovered, at least mostly, but have been very serious about water safety since then. My discomfort clearly sucked, but, more importantly diarrheal disease, mostly caused by water and food contamination, is the second leading cause of death for children under 5 years old and results in the deaths of over 750,000 children every year. It is largely preventable.

The options for eliminating water infection risk are many, and all have pros and cons. Some are new, some are old. I think I know about nearly all of them. To avoid water related disease, we must kill or remove parasites, their eggs, bacteria and viruses. We can use chemicals, filters or radiation to do this. The simplest and oldest effective method of water purification is boiling. If water is boiled for a minute, virtually all microorganisms are killed and it will be safe to drink. Chlorine is toxic to just about every living thing and a little less than a teaspoon of bleach added to 5 gallons of water and left to sit for 30 minutes (the chlorine molecules must reach all of the intended targets) will be safe to drink. The EPA quotes 8 drops of bleach to sanitize 1 gallon of water. If it is left awhile the chlorine gradually evaporates and the taste improves, though it is not bad at all at this level. One must remember that bleach does lose potency over time, and that these proportions apply to fresh bleach, 5-6% sodium hypochlorite. Chlorine dioxide is a more potent bactericide than bleach but is harder to find and more expensive. It comes in both tablets and liquid and leaves virtually no chlorine taste. Aquamira is the product I have used. Povidone iodine, the 10% solution that is used as a medical skin prep, is effective at a concentration of 1:1000, which means 1 ml (15 drops) in a liter of water, when left for 15 minutes. It also doesn't taste too bad, but will turn purple if mixed with starch, so is quite alarming if used to cook pasta. Tincture of iodine and iodine tablets are more potent but a little harder to come by.

Ceramic filters, like those used for backpacking, remove all but the smallest viruses. Unfortunately hepatitis A and E, which cause lots of bad disease in developing countries, are not removed by ceramic filters and can be present and infectious in water. These filters, like the Katadyn pocket water microfilter and the MSR Sweetwater, are very compact and can be used to remove bacteria and protozoa from huge quantities of stream water, as well as removing undesirables like pine needles and algae and grit. They are absolutely fine for most uses but are not adequate, alone, for places where virus contamination is an issue.

A few years ago a British engineer came up with a super fine filter that eliminates viruses as well and is very simple to use. The name of the company is Lifesaver and it has been marketed to the military and well as being introduced into water limited settings where people drink from puddles with obvious contamination. I got one of these because I was impressed with the demonstration video and could see how it would potentially save lives. They make 750ml bottles, which I bought, and big multiple gallon jugs which can be filled from any water source, even really nasty ones, and then a low pressure pump pushes the water into a reservoir from which it can be used. The contraption is heavy, about a pound and a half, but tough and easy to use. I used it exclusively in Tanzania and was blissfully without intestinal ills. It costs nearly $200 and is rated to be able to purify 6000 liters before the filter needs to be replaced. They recommend replacement of the charcoal filter after each expedition, but that is not required for safety.

The most surprising technology to me is ultraviolet (UV) light treatment. UV light has been used for water purification for decades, but recently small pocket lamps have become commercially available which can be used on the fly. Ultraviolet light attacks DNA and RNA, the genetic materials of cells, and kills everything whose function depends on these, which is basically everything. The UV radiation in these devices is very high frequency and depends on the water being nearly completely clear to work. It cannot penetrate particles of poo floating in water. It is an excellent way to treat water from the tap or water that has been filtered or is visibly without particles. UV light is increasingly used to treat city water sources since it doesn't depend on toxic chemicals to work. It does, however, depend on electricity. I bought a steripen, which is a device about the size of an electric toothbrush, which recharges from a USB port. I also have a solar battery which a USB output so I am set, but some of the pens require rechargable AA batteries which are a little less flexible in resource poor settings. With the pen, you simply press a button on the handle and stir the water in a liter bottle for 90 seconds until the pen indicates the process is complete. Camelback makes a bottle with the UV source built in, also with a rechargeable battery with a USB connection. These contraptions all cost around $100. It is also possible to purify water by placing it in a PET plastic container in full sunlight on a roof for 6 hours, using both the heat and the UV to kill anything living in it.

I'm headed to Haiti and South Sudan in the next two months and will bring my Lifesaver bottle and Steripen, with some povidone 10% for backup. I will eat cooked food or fresh fruit that I can peel. I absolutely promise not to drink the delicious glasses of whatever they offer me even if I know they will taste amazing and I am very thirsty. Except tea if I see the water boil. That is really the hardest thing. Not eating cabbage salad. Not drinking the glasses of yummy juice punch. I will remember what it was like to be nauseated for a month with a swollen liver. I will use hand sanitizer and then wash my hands, whenever there is water available to do so. In Haiti we will again work on projects to improve waste disposal and promote water purification (bleach treatment is probably the most practical there). My resolve is firm, my research extensive and my experience instructive.