Cancer actually on the rise?

[iPeppers]

I don't know a lot about this topic, and cancer in general, but I am just curious...

 

Do we actually know for sure that cancer in on the rise, or has any more potential to affect people now, than it did in the past?

 

The reason I am asking is because I have heard that because of what cancer actually is (very basically, cells that have been damaged, causing them to replicate out of control, and have no real beneficial function anymore), every cell would eventually end up cancerous if it was able to live long enough for it to be naturally damaged in such a way to turn it cancerous. This, along with the fact that people have a much longer life expectancy than they used to many years ago, and that our records of illnesses and causes of death are much more complete in this day of age... this all led me to think, what if the reason that cancer is so much more prevalent as a cause of death now, could be mostly because of a couple simple facts;

 

-people didn't used to live long enough, way back in the day, for their cells to have the higher probability of turning cancerous, that they do as they become older. (I realize that younger people can get cancer as well, but a much higher percentage of people tend to get it as they get older.)

-before cancer was understood as what it is today, many many deaths may just have been written off as mysterious unknown deaths, or natural causes. So, now that we have started recording more deaths by cancer as actually being by cancer, it makes it look like cancer is on the rise (possibly much more so than it actually is?).

 

Are these ridiculous assumptions? Thoughts?

[CharonY]

Essentially you are on the right track. It depends a little bit on how you assert that cancer is on the rise as you implicitly proposed two different metrics. First is by tracking the proportion of the population that actually gets cancer. This is more correct if you want to directly measure the occurrence of cancer, though this includes lethal as well as non-lethal outcomes. In this case for instance improved diagnostics may be responsible for increased detection of cancer that may went unnoticed otherwise. It should be noted that depending on severity and kind of cancer people can die with instead of by cancer.

An alternative way is to look at the proportions of deaths caused by cancer. For this metric both your hypotheses are reasonable assumptions. Other forms of death may have been more prevalent. One could test this by breaking down the cancer deaths. For instance taking a look at the age of with which cancer death occurs.

[iPeppers]

Interesting, I didn't even consider that many people may have died with cancer, but not because of it. And that could still happen much more today if it wasn't for medical screening advances that technically may cause many people to go through cancer treatments even though they will end up dying from something else first.

 

So, is there any evidence that cancer is indeed on the rise and much more prevalent in this day of age, because of radioactive or chemical effects? (compared to long ago, when man-made materials and chemical and radioactive disasters and such did not exist) It seems everything in this day of age is either being labeled as either a possible cancer causer or a possible cancer preventive. Why bother? Or is it just a media thing?

[CharonY]

I have no hard data right now, but I would be surprised if cancer rates are indeed increasing significantly due to biological reasons (rather than due to enhanced detection rates). It will be tricky to separate that, though as obviously reporting cancer occurrences is dependent on the techniques of detection used. Why bother? Well obviously everyone is going to die of something, but good cancer prevention may enhance life span a bit as well as possibly increasing end of life quality. Also the value of going against cancer forms that are more common early in life have obvious advantages. Thing is, one should keep everything in perspective. Only because it is not increasing in frequency does not mean it won't affect you or your beloved.

It is kind of a disease of modern times that only what is in the recent media will get any attention, and the sheer amount of available info makes it hard to separate crap from real important

info.

Edit: ok the last bit was a general rant without really being on-topic

 

Edit2: actually certain cancer types, possible associated with diet may be increasing somewhat. Also skin cancer may increase in areas where ozone has worn off. Though of course it is tricky to define where to set the baseline from which one would calculate the increase.

Edited September 23, 2009 by CharonY

[AlexTehManiac]

Cancer is a sticky subject really, I know 2 people close to me died of it, and one person that is close to me may be suffering from the <....>'ing vaccine. It is mainly a duplication of malicious cells, yes, you're right, but it can't be completely treated, no offence to anyone but take jade goody as an example, she fought it as much as she couuld using kimotherapy and radiotherapy.

 

It didn't work and she sadly passed away eventually, but once you have it, you're stuck with it, unfortunately. I'm not really sure how it works and I'm not sure if it is on the rise but it's definately something that will spark an interesting subject on here. I'll do some studying on it and get back to you.

 

[Edit]: I found a bit of information the wikipedia. "Cancer may affect people at all ages, even fetuses, but the risk for most varieties increases with age. Cancer causes about 13% of all human deaths. According to the American Cancer Society, 7.6 million people died from cancer in the world during 2007. Cancers can affect all animals." - it looks to be on the rise a hell of a lot, 7.6 million is alot of people. I'm not sure about the death toll here in England but alot of people I know have been touched by the horrible disease, and unfortunately, passed away. [R.I.P Chris..]

 

It can also cause genetic abnormalities in two types of genes, also.

Edited September 29, 2009 by AlexTehManiac

[SH3RL0CK]

the risk for most varieties increases with age

 

So since people are now living much longer today than they were in the past (due to better medical knowledge), it should be expected that cancer is more common now. During the stone age cancer was probably rare because most people died before reaching 40 years old. Now that people live to nearly (on average) 80, there is more opportunity for cancer.

 

What is difficult to deduce however, is if some of the increase is due to chemicals we are exposed to that simply weren't around during the stone age.

[iPeppers]

So since people are now living much longer today than they were in the past (due to better medical knowledge), it should be expected that cancer is more common now. During the stone age cancer was probably rare because most people died before reaching 40 years old. Now that people live to nearly (on average) 80, there is more opportunity for cancer.

 

What is difficult to deduce however, is if some of the increase is due to chemicals we are exposed to that simply weren't around during the stone age.

 

Exactly! This is what I was getting at. I wanted to know if anyone actually knows for sure that cancer is on the rise due to unnatural, or man-made problems, such as chemicals.

 

It seems to me, that it may just be the natural order of things. ie. we live longer, therefore cancer is a more common death than it used to be, and we are able to detect it better. The media tends to hype up cancer, and seems to be telling me that it is on the rise (and because I also have had people die from cancer who were close to me, I think that in this case the media hype is for once a good thing), but I want evidence that this is actually the case.

[CharonY]

It is hard to prove a negative...

[iPeppers]

It is hard to prove a negative...

 

True. So how about this.... Why is it that certain chemicals and foods are considered cancer causing, while others are being labeled as cancer preventing (such as most green vegetables)? What are the active ingredients, and how can scientists say that some things cause cancer, and some don't? Why do some things cause cancer?

[CharonY]

Actually potential carcinogens are all substances that have some amount of mutagenic properties. An actual link to cancer does not need to be shown, nor is it likely to be found unless someone gets contaminated with something in extreme amounts. Cancer preventing is mostly a non-scientific term.

It is used by nutritionist (and about everyone else) either based on a association studies that found that populations with a certain diet have lower incidents of certain types of cancer (those there may be confounders and usually there are few if any proposed mechanisms). There is to my knowledge nothing that is truly cancer preventing inasmuch as it has a real mechanistic effect. Especially given the fact that the precise mechanisms of cancer cells is not understood either.

[Mr Skeptic]

True. So how about this.... Why is it that certain chemicals and foods are considered cancer causing, while others are being labeled as cancer preventing (such as most green vegetables)? What are the active ingredients, and how can scientists say that some things cause cancer, and some don't? Why do some things cause cancer?

 

Generally, some foods act anti-oxidants, which means that they eliminate free radicals, dangerous chemicals that can damage DNA or proteins. Carcinogens are anything that does that opposite; any tendency to cause molecular damage would indicate a carcinogen, regardless of any studies linking it specifically to cancer.

 

I recall reading an article recently that cancer screening may increase mortality. Newer screening techniques can detect very small tumors. Some are benign tumors, and apparently some types of cancerous tumors will die out on their own. But here's the kicker: cancer treatment is very, very nasty. But when people find they have a tumor, they tend to opt for the treatment anyways.

[GDG]

Generally, some foods act anti-oxidants, which means that they eliminate free radicals, dangerous chemicals that can damage DNA or proteins. Carcinogens are anything that does that opposite; any tendency to cause molecular damage would indicate a carcinogen, regardless of any studies linking it specifically to cancer.

 

Approximately true, but carcinogens are generally compounds that have certain effects like binding to DNA. A compound that is just a strong oxidizing agent simply kill cells outright, without inducing cancer. If you drink a beaker of potassium permanganate, you won't have time to develop cancer

 

Some carcinogens intercalate, or stack in between bases in the helix, which can cause reading and transcription problems. Other carcinogens chemically modify bases, which can cause the base to be misread, or in some cases can cause the cell to apoptose. Other carcinogens may interfere with regulatory proteins. A number of specific events must happen within a cell for cancer to occur. For example (and this is not a complete list), the cell must replicate inappropriately; the cell must escape apoptosis, which is the cell's usual failsafe against inappropriate or defective replication; the cell must restore its telomeres (i.e., activate its telomerase); the cell must overcome the contact inhibition on growth (which lets the cell continue to divide despite overcrowding), and so on.