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Tuesday, July 30, 2013

When cancer isn't cancer at all

Overtested Americans: When cancer isn't cancer at all

By Jacque Wilson and Amanda Enayati

The patient slammed his fist on the table in Dr. Otis Brawley's office.

"Dammit, I'm American," Brawley remembers him saying. "You can't tell me I have prostate cancer and that we're just going to 'watch it.'"

Brawley is the chief medical officer for the American Cancer Society, a world-renowned cancer expert and practicing oncologist. If you're going to get someone's opinion on a cancer diagnosis or course of treatment, he's a good choice. And in this case, he was recommending no treatment.
It's a scenario that may happen more as science reveals cancer's secrets, the biggest one being that what we now call cancer maybe shouldn't be called cancer at all.

"The word 'cancer' often invokes the specter of an inexorably lethal process," a working group for the National Cancer Institute wrote in a recent recommendation. "However, cancers are heterogeneous and can follow multiple paths, not all of which progress to metastases and death."

Basically, cancer is scary, but some kinds may be more boogeyman-in-the-closet scary than serial killer scary.

To understand fully, you have to look at the history of cancer diagnosis, Brawley says. In the 1850s, a group of German pathologists did some of the first biopsies on people who had clearly died of cancer. They took samples of their tumors and decided what breast cancer looks like, what lung cancer looks like, etc.

Today, Brawley says, there is a patient who has a lesion that's approximately 5 millimeters in diameter -- smaller than a pea. There's a doctor taking a biopsy of that lesion and a pathologist who's analyzing the sample using 21st-century technology. The problem, Brawley says, is that they're still comparing the samples to the cancer definition that was created more than 150 years ago.

"He's going, 'This looks just like what those Germans said is breast cancer,' " Brawley said of the pathologist. "But it's 5 millimeters in size. What killed the woman 160 years ago had spread all throughout her body."

We all harbor abnormalities, says H. Gilbert Welch, Dartmouth professor of medicine and author of the book "Overdiagnosed: Making People Sick in the Pursuit of Health." And new technology is increasingly able to find these abnormalities. When we do, our inclination is to act, even when the remedy turns out to be far more harmful than the disease would have been, had it run its course.
There is a growing consensus, backed by mounting scientific evidence, that Americans tend to be overtested, overdiagnosed and overtreated across a variety of conditions. Some experts estimate that unnecessary interventions account for 10% to 30% of U.S. health care spending.

Part of the problem is our medical culture, Welch says. The physician may be engaging in what is known as "defensive medicine," which entails ordering tests to guard against malpractice suits, should something go awry. There may also be perverse economic incentives at play -- that is, in a fee-for-service system, doctors are compensated for the quantity of tests and procedures they order.
But a recent study of physicians with the U.S. Department of Veterans Affairs found that salaried physicians who received no income from an increased volume of services and who had limited liability concerns ordered as many heart stress tests deemed "unnecessary" as doctors in more traditional settings.

The researchers theorized that the doctors had "an exaggerated perception of benefit" of the tests. In an editor's note on the study, Dr. Deborah Grady observed that while the study sample was small, "neverthless, it suggests that the culture of overdoing is ingrained."

Simply put, physicians are trained to think that the way you take care of people is to "find stuff and to take care of that stuff," Welch says.

Patients aren't exactly helping the issue, either. Energized by public awareness cancer campaigns, many patients have been empowered to find cancer early through screening and to intervene as soon as possible, Welch observes.

"To raise awareness and to get people to participate in screening, we have to whip up fear; we must introduce a bit of 'dis-ease' into the population," he said. "In a way, we have to make them feel as if the world may be a more dangerous place and that they ought to be worried about their future."
Brawley's patient, the one he refused to treat, eventually found another doctor who would treat his prostate cancer. "Patients will doctor-shop until they get what they want," Brawley said.

It's an issue many people have difficulty wrapping their heads around: Some patients who are diagnosed with cancer do not need to be treated, because that cancer is never going to bother them. The problem is that we don't know who those people are.

"There is a lot of work and research in this area in trying to better characterize which tumors will matter," Welch said.

The National Cancer Institute working group made several recommendations for the medical community in addressing cancer overdiagnosis and overtreatment. One was a change in the terminology doctors use to talk about cancer, especially when the cells they've found may not be dangerous.

"Use of the term 'cancer' should be reserved for describing lesions with a reasonable likelihood of lethal progression if left untreated," they wrote.

They also noted that the public should be made aware that overdiagnosis is common in cancer screening.

Doctors know that approximately 10% of localized lung cancer tumors and 20% to 30% of localized breast cancer tumors that are found through screening would never cause harm, Brawley says. "That tumor would just stay there: never grow, never spread." The rate is even higher for prostate cancer at 60%.

But isn't screening used to catch some aggressive cancers in people that we would otherwise see too late to treat?

Some overdiagnosis is acceptable, Brawley says. "We cure and treat some people who don't need to be treated. And in return, we save some lives." But screening has its own dangers.

Whenever you test a population, you will have some false positives. For example, if a woman is told that her mammogram is abnormal, that diagnosis might be straightened out days or weeks later, and she might find out that she does not have cancer. The diagnosis will create anxiety and lead to additional unnecessary testing.

Good health is more than absence of physical abnormality; it's also a state of mind, experts say.
"In my experience, it's not the diagnosis of cancer which really kills people," said Ezekiel Emanuel, a former oncologist, vice provost for global initiatives and chairman of the Department of Medical Ethics and Health Policy at the University of Pennsylvania. "It's the uncertainty."

The National Cancer Institute group recommended reducing the frequency of some screening examinations, focusing that screening on high-risk groups (e.g. screening smokers for lung cancer) and raising the requirements that would lead to a biopsy or other follow up care.

"We've been taught that cancer is a terrible thing and the way to deal with it always is to find it early and cut it out," Brawley said. "We're starting to realize that that is not true in all cases."

Wednesday, July 24, 2013

Weird facts about Sex and Childbirth

5 questions you'd never think to ask about childbirth

By Robert Martin

The evolutionary background of human reproduction can shed much-needed light on some of life's most intimate mysteries.

In my book, I trace our reproductive lifeline back to its earliest roots, revealing the hard science -- and the primate origins -- behind sex cells, mating behavior, gestation and the way we care for our young.

My main aim is to deal with issues that are of practical importance in everyday life. In that light, here are some of the questions that I tackle.

1. Why are a man's testes located outside the body?

In most mammals, including all primates, the testes descend from their initial position next to the kidneys into a pouch-like scrotum outside the body cavity.

Descent of the testes has been explained in various ways.

The most widely accepted explanation is that descent of testes is connected with the raised body temperature that is typical of mammals. It has often been baldly stated that sperm production cannot take place at body temperature. We know, for instance, that infertility results if a man's testes remain in the body cavity. Yet sperm production clearly can take place inside the body, because some mammals -- such as dolphins, rhinoceroses and elephants -- produce sperm with testes that do not descend.

Instead, it seems that a lower temperature is better for sperm storage. Mammals with undescended testes have various special adaptations to store sperm at sites where the temperature is lower.

2. How many sperm are needed to ensure fertilization?

The short answer is that only one sperm is needed to fertilize an egg. Indeed, it is disastrous if an egg is fertilized by more than one sperm as only one set of paternal chromosomes should be provided.

There are special mechanisms to prevent more than one sperm from fertilizing an egg. Yet the average human ejaculate contains a quarter of a billion (250 million) sperm.

Why so many? Several surveys have shown that men who have ejaculates containing fewer than 60 million sperm tend to have fertility problems. Moreover, fertility improves as sperm counts increase from 60 million to about 200 million sperm. But any further increase seems to have no effect on fertility.

We do know that the large number of sperm initially ejaculated is whittled down and that only a few hundred end up close to the egg. Part of that reduction in numbers clearly serves to remove unsuitable sperm. For instance, deformed sperm are filtered out by the mucus in the neck of the womb (cervix), and it seems likely that further filtering occurs in the oviduct (a tube allowing for the passage of eggs from an ovary). So large numbers of sperm are presumably needed to ensure that one high-quality sperm reaches the target.

3. Is it true that human sperm counts are declining?

Since 1974, various surveys have indicated that human sperm counts have been reduced by about half in several industrialized populations over the past 60 years or so.

But that conclusion has been challenged for various reasons, notably because some studies found no evidence for a decline in sperm counts. It has turned out that this is because there are marked differences in occurrence and timing between regions. It was also suggested that reductions in sperm numbers were an artifact arising from changes in counting methods.

However, the same methods have been used to assess sperm counts in farm animals such as cattle, sheep and pigs, and no decline in numbers has occurred. Human sperm counts have not yet declined to levels where fertility is severely threatened, and decreases may be leveling off.

More worryingly at this point, declining sperm counts are accompanied by a marked rise in abnormalities of the male reproductive system -- undescended testes and abnormal development of the penis -- in tandem with higher rates of testicular and prostate cancer. The evidence suggests an environmental effect of some kind that is only affecting humans. Several factors have been implicated, but prominent candidates are environmental toxins that mimic the action of steroid hormones.

4. Is there a distinct fertile window in a woman's cycle?

The "egg-timer" model of the human menstrual cycle, with ovulation and conception regularly occurring close to midcycle, has formed the basis for medical thinking and intervention since the 1930s. This model needs radical revision.

The notion of regular midcycle ovulation is itself just a statistical abstraction. Menstrual cycles show considerable variation both in length, routinely ranging between three and five weeks, and in timing of ovulation relative to menstruation.

More important, however, several lines of evidence lead to the revolutionary conclusion that sperm are stored in the human womb, probably in crypts in the cervix. This means that intercourse leading to conception can occur up to 10 days or more before ovulation takes place.

This raises major problems for the "rhythm method" of contraception, which relies on the accepted wisdom that sperm and eggs have strictly limited maximum life-spans, surviving for only two days and one day, respectively. In practice, the rhythm method (even with refinements) is very unreliable.
Worse yet, deliberate avoidance of intercourse around the time of ovulation can be confidently expected to increase the risk of fertilization with a time-worn sperm or egg and hence the probability of fetal abnormality. Various studies have indicated that this is, indeed, what happens.

5. Why is human birth such a long and painful process?

Human birth is a challenging process usually lasting several hours, rather than just an hour or two as in monkeys and apes. This is because our newborns are unusually large -- twice as big as babies of great apes -- and have particularly large brains.

During birth, the human baby rotates in a complex manner, with the result that its head normally ends up facing toward the mother's back rather than to the front, as in other primates. Measurement reveals that the size of the newborn's head is pushed to the limit. Biological dimensions generally fit a standard bell curve, which statisticians call a normal distribution. But the curves are truncated at the upper end for the newborn's head and at the lower end the size of the pelvic canal.

In a process called "genetic pruning," natural selection has acted against over-large heads and small pelvic canals. The fit is still so tight that the human brain also has to grow an unusual amount after birth. In other primates, the newborn's brain is about half its adult size, but in humans it is only a quarter of adult size.

So, despite the large size of human newborns and their brains, additional rapid brain growth after birth is needed.

Thursday, July 18, 2013

Union to meet midwives amid obstetrics closure

The Nursing and Midwifery Federation will today meet midwives at the Millicent Hospital to discuss their futures.
Country Health SA last week announced plans to close obstetric services at the hospital because of a lack of doctors with obstetric and anaesthetic skills and a drop in births.
The decision has caused a community backlash, with the local mayor saying it goes against assurances that the service would remain intact.
The federation's Rob Bonner says he wants to meet Country Health SA before it finalises the plan.
"We would hope that Country Health SA will listen to our members, will listen to the local community and local government and revisit this kneejerk decision it's announced last week," he said.
He says about six midwives at the hospital stand to lose their jobs.
"Those midwives now are being asked ... to make decisions about where they see their personal and professional futures," he said.
"At least one midwife has already moved her employment to Mount Gambier so she can remain actively practising in the area.
"Others are considering whether they want to do the same."