Pot, Lung Cancer Not Linked

A new study from UCLA finds no link between marijuana smoking and lung cancer. Some details from a Reuters report:

The study, which compared the lifestyles of 611 Los Angeles County lung cancer patients and 601 patients with head and neck cancers with those of 1,040 people without cancer, found no elevated cancer risk for even the heaviest pot smokers. It did find a 20-fold increased risk of lung cancer in people who smoked two or more packs of cigarettes a day……
Previous studies showed marijuana tar contained about 50 percent more of the chemicals linked to lung cancer, compared with tobacco tar….In addition, smoking a marijuana joint deposits four times more tar in the lungs than smoking an equivalent amount of tobacco.

[Dr. Donald Tashkin] theorized that tetrahydrocannabinol, or THC, a chemical in marijuana smoke that produces its psychotropic effect, may encourage aging, damaged cells to die off before they become cancerous.

In an earlier discussion of his research on pot and cancer, Dr. Tashkin even offered that, given his data, it is not an unreasonable hypothesis to further explore that marijuana just might have some protective effect against lung cancer.

Comments

[sage +P]

In other news, the UCLA medical center was denied all further government research grants. "If they're not going to find the results we want, then we'll take our ball and go home," a spokesman said.

[smacky]

*Yawn*

This is old hat. There were studies done like this years ago that I knew of in my purple-haze youth. Toke on.

[taktix]

Light 'em up!

[Mr. Nice Guy]

I'm definitely breathing easier.

[Brian]

In addition, smoking a marijuana joint deposits four times more tar in the lungs than smoking an equivalent amount of tobacco.

Which, of course, is the rub. Anyone who has smoked both MJ and tobacco knows that no one smokes an amount of MJ equivalent to the amount of tobacco someone with a 20-fold increased risk of lung cancer has to smoke.

[uncle sam]

And it is not necessary to burn mj to enjoy psychoactive benefits. Vaporizers.

[Patrick]

Previous studies showed marijuana tar contained about 50 percent more of the chemicals linked to lung cancer, compared with tobacco tar

That's an overgeneralization. Cannabis smoke condensate does appear to be rich in PAHs, which are one of the major classes of carcinogens in tobacco smoke. However, cannabis smoke lacks the tobacco-specific nitrosamines, which are the other major class of tobacco smoke carcinogens.

There are other relevant differences too. See for instance:

Melamede, 2005. Cannabis and tobacco smoke are not equally carcinogenic. Harm Reduction Journal 2:21.

*Yawn*

This is old hat. There were studies done like this years ago that I knew of in my purple-haze youth. Toke on.

Nope. I have looked at the literature pretty exhaustively, and can tell you that there have been no reasonably good epidemiological studies of cannabis and lung cancer until the 1990's, and even those left much to be desired.

[Clean Hands]

Wow, man. 🙂

How about a cigarette containing a mixture of tobacco and cannabis, so you can get your nicotine fix, your THC, and moderate your lung cancer risk?

[Pirate Jo]

What about that stuff they put into cigarettes to keep them burning? I don't know what it's called, but I hear that's one of the worst things in them. I wonder if people who purchase fresh tobacco and roll their own cigarettes have a lower incidence of cancer than those who purchase them by the pack. That would make an interesting study, too.

[Patrick]

What about that stuff they put into cigarettes to keep them burning? I don't know what it's called, but I hear that's one of the worst things in them. I wonder if people who purchase fresh tobacco and roll their own cigarettes have a lower incidence of cancer than those who purchase them by the pack. That would make an interesting study, too.

I've read a lot of journal articles on tobacco smoke carcinogens, and apparently no one things that cigarette additives play a significant role in tobacco carcinogenesis. For instance, Hecht (2003) doesn't even mention additives in his review of tobacco carcinogens. Also, I do recall that epidemiological studies of bidi smokers in India show relative cancer risks as higher or higher than those seen in normal cig smokers, and my understanding is that bidis do not contain all the additives in typical western tobacco. Could be wrong on that though.

Hecht, 2003. Tobacco carcinogens, their biomarkers and tobacco-induced cancer. Nature Reviews Cancer 3. 733-744.

[zach]

So, one study. I'm sure there will be another to rebut it before too long. I'll go on with the assumption that smoking anything is bad for you, but this will be interesting to bring up over a joint tonight.

[Kip]

I read a study last year that pointed to marijuana as a possible protection from brain tumors. I believe it also suggested that thc might help in the receding of cancerous cells when used along with other cancer treatments. I can't find it though, anybody else read it? link?

[Larry A]

<sarcasm> Yeah, but that would send the wrong message in the War on Drugs. Screw the cancer patients.</sarcasm>

That's three today.

[Shannon Love]

I don't know about this. In my personal experience, people who smoke marijuana usually smoke tobacco as well. It would seem difficult to tease out the differences in such a small sample. All the more so because you're trying to get a bunch of stoners to remember how much they smoked.

[zach]

In my personal experience, people who smoke marijuana usually smoke tobacco as well.

Usually, but the self-righteous health conscious hippy demographic sets that off a bit.

[Patrick]

I read a study last year that pointed to marijuana as a possible protection from brain tumors.

Here's something I wrote a few years back about this:

Galve-Roperh et al (2000) demonstrated the tumor supression properties of THC and WIN-55,212-2 (a synthetic, water-soluble cannabinoid) in rat and mice models of malignant glioma, a fatal type of brain tumor that in humans results in death within one year, even with agressive (surgical and chemotherapy) treatment. The effects were fairly dramatic, with a complete eradication of the tumors in 20-35% of the cannabinoid-treated animals, and a doubling of survival time in another third of the animals. Further, the doses used were relatively low, maximum 1.0 and 0.1 mg/kg/day for THC and WIN-55,212-2, respectively.

Galve-Roperh et al, 2000. Anti-tumoral action of cannabinoids: involvement of sustained ceramide accumulation and extracellular signal-regulated kinase activation. Nature Medicine 6, 313-319.

[Patrick]

Correcting for tobacco smoking is not difficult at all, and is routine in studies of disease that are associated with tobacco smoking. Different studies find different rates of tobacco smoking amoung cannabis smokers, but most of them put the % around 50-75%. The bigger limitation of the present study is the young age of the population -- 60 and under. If is quite possible --possible-- that the excess lung cancer risk associated with cannabis smoking is too small to detect in a sample this young and this small will become apparent in a future study including older individuals.

[PiGuy]

Nobody could smoke 20 Js a day like a pack a day of cigs-smoker does. You'd be so stupid that you wouldn't even be able to get your Dead CD to play. At any rate, while it might contain more bad stuff per stick, it seems like it'd be pretty difficult to even smoke 5 fat ones (if pot is 4x harsher than an equal amt of tobacky, 20/4 = 5) and be able to do anything else.

But I do think that it's a good idea for old people. It makes the time go slower.

[smacky]

Nope. I have looked at the literature pretty exhaustively, and can tell you that there have been no reasonably good epidemiological studies of cannabis and lung cancer until the 1990's, and even those left much to be desired.

Patrick,

Um, the 1990's was my purple-haze youth.

[Timothy]

I was just thinking that not even Tommy Chong in his prime could possibly have smoked 40 joints a day like a two pack cig smoker. Can you imagine?

Like Towlie, only worse.

[Warren]

My personal experience is that less than half of pot smokers are cigarette smokers. I only took up tobacco because the military made me give up pot (and they sold me smokes tax-free). It was a hell of a lot tougher giving up the cancer sticks. Oh and of course I picked up the bong just as soon as I was discharged... or maybe a little earlier 😉

[The Widow White]

Thank G_d!

[rst]

How about a cigarette containing a mixture of tobacco and cannabis, so you can get your nicotine fix, your THC, and moderate your lung cancer risk?

We handrolled those (mixed half-and-half) and called them "Ciggy-J's", and they were a great way to smoke copious amounts of ganja in public. They were nearly indistinguishable from Marly lights.

And yeah, I think you'd have to be crazy (or just have a nasty problem) to smoke as much marijuana by volume as a cigarette smoker does in tobacco.

I wonder however, did they control for lifestyle factors? For instance, were these pot smokers the crunchy granola type with healthy inclinations? There seems to be a desire to paint this study as indicative of tumor-fighting properties.

[The Widow White]

I read a study last year that pointed to marijuana as a possible protection from brain tumors. I believe it also suggested that thc might help in the receding of cancerous cells when used along with other cancer treatments. I can't find it though, anybody else read it? link?

I don't have a link, but the prevailing theory is that weed slows down cell division and given that the aging process is due to cell division (we essentially caramelize) slowing it down adds years of life and may serve to contain / reduce tumor growth.

[Paul]

Dr. Tashkin even offered that, given his data, it is not an unreasonable hypothesis to further explore that marijuana just might have some protective effect against lung cancer.

You know, I'm all down with the chronic and whatever else the young people are smoking. But these so-called miracle studies about Marijuana clearing up acne, helping you be a better housekeeper, improving your sex life, your short term AND long term memory, relieving specific forms of sciatica, releiving urinary tract infections, curing obesity (if recently caught), reparing damaged pet wallaby nerve cells and all the other 'amazing' properties of the weed-- I find them questionable. There's reason to believe that marijuana is going to cause just as much lung cancer as as regular smoking would if people would use it at the same rate they use cigarettes. All caused by the simple and continued mechanical irritation of the lung tissues. Breathing foreign particles in large quantities for long periods of time into your lungs tends to cause cancer. So let's just be honest, admit that it's not about any amazing medicinal properties of the chronic that we're trying to bring to the fore, we just wanna smoke our dope. Let's legalize it, and move on.

Quit trying to tell me that it'll take ten years off my face everytime I light up.

[SixSigma]

Paul -

Dude... You're really harshing my buzz.

[Mark]

Nobody could smoke 20 Js a day like a pack a day of cigs-smoker does.

Oh yea?

But these so-called miracle studies about Marijuana clearing up acne, helping you be a better housekeeper, improving your sex life, your short term AND long term memory, relieving specific forms of sciatica, releiving urinary tract infections, curing obesity (if recently caught), reparing damaged pet wallaby nerve cells and all the other 'amazing' properties of the weed-- I find them questionable.

1. Get high
2. have sex
3. believe

[spur]

Paul,

Dr. Tashkin, the guy who did the study is not a 'jonnie one note' marijuana is life guy -- he's a researcher that got paid by the government to find marijuana harmful and tried very hard to find that link -- the fact that he says this and not Keith Stroup or Dr. Dre is very interesting.

[emme]

"I've read a lot of journal articles on tobacco smoke carcinogens, and apparently no one things that cigarette additives play a significant role in tobacco carcinogenesis. For instance, Hecht (2003) doesn't even mention additives in his review of tobacco carcinogens. Also, I do recall that epidemiological studies of bidi smokers in India show relative cancer risks as higher or higher than those seen in normal cig smokers, and my understanding is that bidis do not contain all the additives in typical western tobacco. Could be wrong on that though.

Hecht, 2003. Tobacco carcinogens, their biomarkers and tobacco-induced cancer. Nature Reviews Cancer 3. 733-744."

Why do they add the chemicals in the cigarrettes?
Does it make smoking more addictive? Is there any research on that?

[GreginOz]

Well, I reckon that pot IS a life saver! Heck, without it I would have popped many a nanny-stater long before this!

[Patrick]

Paul wrote:

There's reason to believe that marijuana is going to cause just as much lung cancer as as regular smoking would if people would use it at the same rate they use cigarettes.

I commend you for being skeptical of health claims made for cannabis smoking, but what you say above is just plainly incorrect, as the references I listed above explain in some detail. There is compelling evidence that, on a mass-for-mass basis, cannabis smoke is not equally carcinogenic to tobacco smoke. For instance, Malamede's (2005) review points out the following relevant facts:

". . . while both tobacco and cannabis smoke have similar properties chemically, their pharmacological activities differ greatly. Components of cannabis smoke minimize some carcinogenic pathways whereas tobacco smoke enhances some. Both types of smoke contain carcinogens and particulate matter that promotes inflammatory immune responses that may enhance the carcinogenic effects of the smoke. However, cannabis typically down-regulates immunologically-generated free radical production by promoting a Th2 immune cytokine profile. Furthermore, THC inhibits the enzyme necessary to activate some of the carcinogens found in smoke. In contrast, tobacco smoke increases the likelihood of carcinogenesis by overcoming normal cellular checkpoint protective mechanisms through the activity of respiratory epithelial cell nicotine receptors. Cannabinoids receptors have not been reported in respiratory epithelial cells (in skin they prevent cancer), and hence the DNA damage checkpoint mechanism should remain intact after prolonged cannabis exposure. Furthermore, nicotine promotes tumor angiogenesis whereas cannabis inhibits it. It is possible that as the cannabis-consuming population ages, the long-term consequences of smoking cannabis may become more similar to what is observed with tobacco. However, current knowledge does not suggest that cannabis smoke will have a carcinogenic potential comparable to that resulting from exposure to tobacco smoke. "

Melamede, 2005. Cannabis and tobacco smoke are not equally carcinogenic. Harm Reduction Journal 2:21.

In addition, as I pointed out above, cannabis smoke lacks one of the major carcinogens in tobacco smoke -- the tobacco-specific nitrosamines such as NNK. These are some of the most potent lung carcinogens in tobacco smoke, cause lung tumors in all animal models (including cultured human bronchial cells) regardless of mode of administration, and are thought to play a major role in tobacco associated carcinogenesis.

[Patrick]

Why do they add the chemicals in the cigarrettes?
Does it make smoking more addictive? Is there any research on that?

Well, all additives are there to increase consumer liking/acceptance of the product, so in that sense they could be said to make smoking more addictive. Some additives are for taste and smell, some are to retain moisture in the tobacco and alter burning characteristics, but some compounds, like ammonium compounds, do seem to enhance nicotine delivery in some way, and therefore could be said to enhance the addictive property of tobacco.

[James Ard]

Now if they tell me mj helps the liver I'll be in great shape.

[zach]

We handrolled those (mixed half-and-half) and called them "Ciggy-J's", and they were a great way to smoke copious amounts of ganja in public. They were nearly indistinguishable from Marly lights.

Spliffs. You were rolling spliffs.

[simon]

Hey Hey Hey... Cancer is big business here in America, just like oil. If you cut out the cancer, you cut out alot of money, revenue, tax, etc. So what big bro does, is try to prevent you from smoking marijuana so that you will be sure to get cancer. No matter what you think, your government really doesnt care whether you live or die, so you better start taking care of yourself and trusting in someone else to do it for you...