Breast cancer screening study suggests some tumours may cure themselves

[Celebration]

http://www.telegraph.co.uk/health/healthnews/3512316/Breast-cancer-screening-study-suggests-some-tumours-may-cure-themselves.html

Doctors found more cancers amongst women who were screened every two years compared to those screened once in six years, raising the possibility that some cancers vanish on their own.

This means that some women are going through painful and upsetting treatment, often involving surgery and chemotherapy, for a cancer that would have gone away on it own had it not been detected.

The study was carried out using data from 120,000 women who were screened three times between 1996 and 2001 and compared the number of cancers detected to those found in 110,000 women of the same age who were screened once in six years.

After taking account of various factors that could influence rates of breast cancer, they found the rate of breast cancer in the frequently-screened group remained 22 per cent higher.

Of every 100,000 screened women, 1,909 had breast cancer during the six-year period, compared with 1,564 of every 100,000 in the control group. Screened women were more likely to have breast cancer at every age.

[babylonsister]

1. But what if nothing is done and it doesn't go away? Who's willing

to take that chance?

[HamdenRice]

2. It's not that simple -- removing a tumor may cause dormant cancers to spread

A very complicated picture of the interaction of tumors with the immune system and other tumors is emerging. There was a flurry of fascinating research about angiogenesis.

The basic idea is that in order to grow, a cancer needs to cause blood vessels to grow to feed it. For reasons that aren't clear, many tumors never are able to get blood vessels to grow and they become dormant because they can't grow beyond a very small size. Cancer in other words, may be a more "normal" condition than we thought.

Even stranger, researchers found that some tumors suppress angiogenesis in other tumors. In other words, tumors suppress each other. These researchers found that removing a primary tumor caused small dormant tumors to grow explosively by somehow enabling them to cause blood vessels to grow to feed them once the suppressing action of the primary tumor was removed.

IIRC, they still don't know how primary tumors turn on the switch that allows them to command blood vessels to grow, but they know more about the way primary tumors suppress secondary tumors.

So if the researchers in the OP found that many breast tumors spontaneously disappear a cost benefit analysis might show that aggressive treatment as we now know it may be causing more advanced illness than we thought.

[babylonsister]

3. So a lot more research needs to be done.

Cost-benefit analysis when talking about cancer? I'm obviously not a scientist, but I am a breast cancer survivor who had a m.r. mastectomy when I was 26. I wonder if I'd still be here if not for that surgery and chemo, thus the knee-jerk reaction.

But I'm all for research and updating ideas currently held. Lumpectomies weren't recommended that long ago, so we've come a long way.

[HamdenRice]

5. I'm sorry to hear you went through that

but happy for you that you are healthy -- sounds like many years later.

[Celebration]

7. thanks for this explanation n/t

[kimmerspixelated]

4. The trouble with regular mammograms

is that:

1) You are supplying your body with a dose of radiation.- which makes cancer screening in this fashion a rather ironic choice.

2) If there is a cancer tumor found, the very act of squishing and squashing said breast(s) actually spreads the problem.

HOWEVER: There is a light at the end of the tunnel. THERMOGRAPHY.

www.breastthermography.com


This is at least one place you can look up info regarding this safe method of screening.

[Celebration]

6. see, what I was wondering

I don't know how to interpret the data. Maybe getting a mammogram less often causes people to have fewer breast cancer tumors (???). I do wonder about all the screening guidelines. I wonder if all those mammograms recommended have anything at all to do with curbing mortality.

[salvorhardin]

8. The radiation exposure is relatively small

The effective radiation dose from a mammogram is about 0.7 mSv, which is about the same as the average person receives from background radiation in three months. Federal mammography guidelines require that each unit be checked by a medical physicist every year to ensure that the unit operates correctly. See the Safety page for more information about radiation dose.
http://www.radiologyinfo.org/en/info.cfm?PG=mammo&bhcp=1#part_nine

The actual risk is dependent on age since younger women are more sensitive to radiation-induced cancers. And of course, false positives are likely to result in additional exposures.

[Celebration]

9. well, the results of this need to be explained satisfactorily, somehow

Maybe they are right that cancers spontaneously disappear. It's not false positives, because they are talking about diagnosis of cancer. Or maybe the extra radiation, albeit small, does cause the extra cancer. Of course, people with breast cancer in the family might get more mammograms. I wonder if they controlled for other risk factors, such as a hereditary component.

[cosmik debris]

10. Hmmm?

...since younger women are more sensitive to radiation-induced cancers.

The Law of Bergonie & Tribondeau says that the susceptibility of a cell to radiation is determined by that cell's reproductive rate and its degree of specialization.

Furthermore, cancer risks from radiation are stochastic, not deterministic.

[salvorhardin]

11. Honestly I don't know why I believe that

Probably a half-remembered factoid from some long ago lecture. I just googled to find something that would corroborate that statement but this was all I could find:

Dr. Devra Davis, professor at the University of Pittsburgh Cancer Institute, said women should refrain from mammograms until after menopause to limit their exposure to cancer-causing radiation.

Davis said that women who are at least 40-years-old are the only women who should undergo mammography. However, younger women who have blatant breast cancer symptoms or family histories of breast cancer should receive mammograms earlier. In an interview with breastcancer.org, Davis said younger women are more susceptible to the harmful effects of radiation than older women because their bodies are still developing.

"The vulnerability to the cancer-causing effects of radiation is dependent on the rapid cell growth of a young girl," Davis said. "The younger the age at first exposure, and particularly when exposure takes place at a time of great development, the greater the risk."

According to studies of women in Hiroshima after the atomic bomb, Davis said women under 20-years-old were at higher risks for developing breast cancer by middle age because of radiation exposure. Middle-aged women did not show such increased risks.
http://media.www.mucdynamo.com/media/storage/paper1287/news/2008/02/27/PreventingCancer/Mammogram.Radiation.Risks-3237986.shtml

Sorry if I gave out bad info.

[cosmik debris]

12. The most important information you posted

was the incredibly tiny dose from mammograms. But I doubt that many here would know how to evaluate that dose information. And I would guess that most readers in this forum don't know the difference between stochastic and deterministic.

But I win the trivia prize for the Law of Bergonie & Tribondeau. I paid a lot for that education and I deserve a chance to show it off once in a while. :)

[Celebration]

13. well, if one got a mammogram every year

Then that means a 25% increase in radiation over and above background. That doesn't sound like a tiny increase.

I don't think that any survival studies on having mammograms vs. not having mammograms have shown any difference. Or have they? I mean comparing the death rates of people who get annual mammograms vs. people who don't.......

Are there any studies that women who get annual mammograms live any longer than women who don't?

[cosmik debris]

14. I'm sorry you don't understand

But trying to explain science to you has never been fruitful. So I won't waste my time trying again.

You may take your doctor's advice or you may pretend that you know better than your doctor. It doesn't matter to me.

[Celebration]

15. excuse me?

I asked a simple question.

Are there any studies showing a longer life expectancy for people who have annual mammograms vs. those who don't?

Found a partial answer here--

http://www.scienceagogo.com/news/19980912094305data_trunc_sys.shtml

On those under age 50, it seems mammography adds a few hours, per person, to life expectancy, on average.

The risk of not having a mammogram before age 50 is the same as adding two ounces of weight and keeping it on.

[cosmik debris]

16. Congratulations! Only 37 more searches to get your Dr. Google certificate.

[Celebration]

17. take "it" up with Donald Berry at Duke n/t

[Crunchy Frog]

22. Also, mammograms are less effective for younger women

because of denser breast tissue, where abnormalities are less likely to be visible. My doctor told me this, so it should pass muster with the "skeptics".

[emilyg]

19. Are you a legend in your own mind?

Be polite when someone asks a question.

[salvorhardin]

20. It's still a very small amount of radiation exposure

The SI unit used to express a biological dose of radiation is the Sievert or Sv for short. The lethal dose for a human is usually between 4 and 5 Sieverts. Background radiation is generally about 3 milliSieverts (mSv) per year though. In other words, between about 0.06% and 0.08% of a fatal dose.

Getting a single mammogram increases a woman's yearly radiation dose from about 3 mSv to 3.7mSv. Yes, that's about a 25% increase in radiation exposure. However, that's still only 0.07% - 0.09% of a fatal dose.

Contrast this with Space Shuttle astronauts on long missions who receive about 7,864 millirems per mission. That's just under 79mSv or the equivalent of almost 113 mammograms. Considering that long Shuttle missions average about 2 weeks, you'd have to get 8 mammograms a day, every day, over the course of two weeks just to equal the radiation exposure of a Shuttle astronaut on a single mission.
Source for radiation exposure to Shuttle astronauts: http://www.astronomycafe.net/qadir/q2906.html

[Celebration]

21. I doubt if we have enough data

To do a study on breast cancer incidence among female astronauts. It would be interesting, probably.

[Tumbulu]

23. I wonder if there is data on women who fly on planes regularly

I read that one is exposed to more radiation when flying in an airplane. I wonder how this data could be accessed.

I also interpret the OP article differently than the authors. I do not know why they assume that the tumors go away. How would they know this? They only know that more are found. It could also be that the mammogram itself is raising the rate of tumor formation.

And to all you posters who say 3 months of radiation in 30 seconds is nothing to worry about, that is fine for you to think. But I for one worry about it. Especially reading this report.

And one has no idea how this 3 months of radiation in 30 seconds directed at breast tissue interacts with other factors, say environmental toxins of other kinds. Could there be a synergistic effect?

All this simplistic dismissal of toxic effects based on much higher LD50's is beneath the dignity of the DU community. We all know that LD50's are usually a bell curve with some highly susceptible individuals (canaries in the coal mine) on the low end of the dose spectrum. I for one have no interest in ignoring these individuals.

The well documented advantages of catching a tumor early confound the issue and one is left so very puzzled. I hope that another screening method will be developed. Or a way to reduce dramatically the radiation exposure with this method.

[cosmik debris]

24. There is no LD 50 for radiation induced cancer.

The cancer threat from radiation is stochastic, not deterministic.

You really need to understand that concept to avoid irrational fear.

[Celebration]

25. individual responses to surgery and medicine are also stochastic

Here is a good explanation

http://mdredux.blogspot.com/2007/12/stochastic-and-epistemic-uncertainty.html

That isn't a reason not to collect the statistics.

Certainly there is unaccounted for variation in how different people respond to medicine, radiation, etc.

We don't need to find an LD 50 in order to collect statistics on radiation exposure and breast cancer.

I found this, though--

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1740419

"The association between length of employment and risk of breast cancer, adjusted for reproductive factors, indicates that occupational factors may be an important cause of breast cancer among cabin attendants; the association is compatible with a long induction period."

[Tumbulu]

27. Interesting, thanks for the links

and the good explanations.

[salvorhardin]

26. Right

Which is why when we want to talk about radiation and its effects on the human body we have to talk about the damage done. It's not enough just to measure the intensity of the radiation, but we also have to factor in the type of radiation, and the sensitivity of a particular species or tissue to radiation. That's what Sieverts are a measure of:

Sieverts = Grays (intensity) * Q (type) * N (sensitivity)

[Hannah Bell]

18. They've known some cancers spontaneously disappear (or self-limit) for some time.

I've believed this for some time, too: some of the increase in breast cancer rates is due to increased screening & treatment of small cancers that would otherwise remit or self-limit with no treatment, similar to the case with prostate cancer.

But if one's found, a doc can't ethically not recommend treatment.

But what this study implies is that lives might be saved by screening (& thus treating) less.