Pot not a major cancer risk: report

Yahoo! News ^ | Wed Oct 26,12:29 PM ET | Amy Norton

[JTN]

NEW YORK (Reuters Health) - Although both marijuana and tobacco smoke are packed with cancer-causing chemicals, other qualities of marijuana seem to keep it from promoting lung cancer, according to a new report.

The difference rests in the often opposing actions of the nicotine in tobacco and the active ingredient, THC, in marijuana, says Dr. Robert Melamede of the University of Colorado in Colorado Springs.

He reviewed the scientific evidence supporting this contention in a recent issue of Harm Reduction Journal.

Whereas nicotine has several effects that promote lung and other types of cancer, THC acts in ways that counter the cancer-causing chemicals in marijuana smoke, Melamede explained in an interview with Reuters Health.

"THC turns down the carcinogenic potential," he said.

For example, lab research indicates that nicotine activates a body enzyme that converts certain chemicals in both tobacco and marijuana smoke into cancer-promoting form. In contrast, studies in mice suggest that THC blocks this enzyme activity.

Another key difference, Melamede said, is in the immune system effects of tobacco and marijuana. Smoke sends irritants into the respiratory system that trigger an immune-regulated inflammatory response, which involves the generation of potentially cell-damaging substances called free radicals. These particles are believed to contribute to a range of diseases, including cancer.

But cannabinoids -- both those found in marijuana and the versions found naturally in the body -- have been shown to dial down this inflammatory response, Melamede explained.

Another difference between tobacco and marijuana smoking, he said, has to do with cells that line the respiratory tract. While these cells have receptors that act as docks for nicotine, similar receptors for THC and other cannabinoids have not been found.

Nicotine, Melamede said, appears to keep these cells from committing "suicide" when they are genetically damaged, by smoking, for instance. When such cells do not kill themselves off, they are free to progress into tumors.

THC, however, does not appear to act this way in the respiratory tract -- though, in the brain, where there are cannabinoid receptors, it may have the beneficial effect of protecting cells from death when they are damaged from an injury or stroke, according to Melamede.

All of this, he said, fits in with population studies that have failed to link marijuana smoking with a higher risk of lung cancer -- though there is evidence that pot users have more respiratory problems, such as chronic cough and frequent respiratory infections.

If marijuana does not promote lung cancer, that could factor into the ongoing debate over so-called medical marijuana. Melamede said he believes "marijuana has loads of medicinal value," for everything from multiple sclerosis, to the chronic pain of arthritis, to nausea caused by cancer treatment.

U.S. government officials, however, maintain that the evidence for medical marijuana is not there. Ten states allow people to use marijuana with a doctor's prescription, but the Supreme Court has ruled that federal law trumps state law.

SOURCE: Harm Reduction Journal, October 18, 2005.

[JTN]

One mitigating factor left out of the article is the fact that the average marijuana smoker will smoke far less than the average tobacco smoker.

Some of the anti-pot propaganda has been to claim that marijuana is actually more likely to cause cancer than cigarettes. Perhaps this study will help put that to rest.

[JTN]

ping

[KarinG1]

Yeah, but what about the gunshot wounds? I've seen the movie 'Reefer Madness' more than once, so I am well aware of exactly how dangerous this drug really is.

[libertyman]

You're right--I used to be a tobacco addict, & I quit almost 3 yrs ago (THANK GOD!). When I smoked cigarettes, I averaged about 25 cigarettes a day...& if 2 hours went by & I didn't light up again, my body wouldn't let me ignore the suffering I went through, either.

On the other hand, I enjoy smoking marijuana, & when I do, I will smoke about 1/2 a joint, just enough to get a decent buzz. I'll put it out & smoke the rest of it much later, oftentimes the next day. No addiction, no fuss.

[Rome2000]

This is pro druggie propaganda BS.

Smokers who get lung cancer usually smoke for at least 20 years a pack a day.

Nobody can smoke that much pot and still function.

[Jaysun]

Yeah, but what about the gunshot wounds? I've seen the movie 'Reefer Madness' more than once, so I am well aware of exactly how dangerous this drug really is.

Good point. It also causes some to eat enormous amounts of food - vulgar amounts, really. And that can't be helpful.

[libertyman]

Hmmmmmmm...I never knew marijuana would cause that to happen to anyone. I've enjoyed smoking marijuana for 28 years, & NOT ONCE have I ever come across a situation where vioence occurred.

Could it be that the marijuana laws themselves were respomsible for creating such violence?

[libertyman]

ping

[Trampled by Lambs]

You're right.. It just makes you lazy & stupid.

..and I speak from experience as well.. I smoked it from about 1972 through the early 1990's.

[JTN]

Smokers who get lung cancer usually smoke for at least 20 years a pack a day.

Well that's pretty what I said in my original comment on the article, but that is just one more reason that cancer has not been observed to be more common in chronic cannabis smokers.

[JTN]

Yeah, but what about the gunshot wounds? I've seen the movie 'Reefer Madness' more than once, so I am well aware of exactly how dangerous this drug really is.

Cute. I've never seen reefer madness, but I've heard that it's hilarious.

[pageonetoo]

You're right.. It just makes you lazy & stupid.

It isn't the drug, dude...

[JTN]

It isn't the drug, dude...

Remember, never feed a troll.

[binreadin]

This article is very misleading and a good example of why a lot of these so called Public Health articles are BS. I work in this field, and I can tell you anecdotally at least (and we are talking thousands of cases I've reviewed) that although pot smokers don't seem to have an increased risk of lung cancer, they do seem to have very high rates of head and neck cancers. These cases usually involve men in their 40s-60s, and most of the ones I've seen also smoke tobacco. Also, epidemiologically speaking they do not have a method in the cancer case reporting programs to record whether or not a person smokes pot. We do collect tobacco and alcohol information, and in the military and VA hospitals Agent orange, Asbestos and Chemical Exposure information is collected as well. THERE IS NO ONE on a national, sustained basis collecting information on mariuuana smokers and cancer.

[rlmorel]

LOL!

When I was in High School, I knew a few guys who TRIED!

[rlmorel]

I really thought the part where the guy plays the piano in a REALLY maniacal way, looking back over his shoulder was the funniest damn thing...wish I had a little animated GIF of that!

[Trampled by Lambs]

Dude, yes it is.

Or at least, in many cases it is. This is my opinion after about 30 years of being around pot smokers and being one myself.

Also, it's a matter of degree. I know of many folks that smoke daily and still lead productive lives. But I believe those to be in the minority. Many more I know are in their 40's and still live with their parents or can't hold a job etc.

Then there are ones like me that wake up one day and realize that they've spent the first half of their adult lives in a haze of pot smoke and are nowhere near where they want to be in life because of it.

But I'm feeling much better now...

[pageonetoo]

click for link..

The U.S. federal government spent over $19 billion dollars in 2003 on the War on Drugs, at a rate of about $600 per second. The budget has since been increased by over a billion dollars.

In 2002, 45.3 percent of the 1,538,813 total arrests for drug abuse violations were for marijuana -- a total of 697,082. Of those, 613,986 people were arrested for marijuana possession alone. This is a slight decrease from 2000, when a total of 734,497 Americans were arrested for marijuana offenses, of which 646,042 were for possession alone.

[pageonetoo]

In 2004, 44.2 percent of the 1,745,712 total arrests in the US for
drug abuse violations were for marijuana -- a total of 771,605.
Of those, 684,319 people were arrested for possession alone.
By contrast in 2000, a total of 734,497 Americans were arrested for
marijuana offenses, of which 646,042 were for possession alone.

Marijuana Arrests and Total Drug Arrests in the US
Year Total Drug Arrests Total MJ Arrests
2004 1,745,712 771,605
2003 1,678,192 755,186
2002 1,538,813 697,082
2001 1,586,902 723,628
2000 1,579,566 734,497
1999 1,532,200 704,812
1998 1,559,100 682,885
1997 1,583,600 695,201
1996 1,506,200 641,642
1995 1,476,100 588,964
1990 1,089,500 326,850
1980 580,900 401,982

Year MJ Trafficking/Sale Arrests MJ Possession Arrests
2004 87,286 684,319
2003 92,300 662,886
2002 83,096 613,986
2001 82,519 641,109
2000 88,455 646,042
1999 84,271 620,541
1998 84,191 598,694
1997 88,682 606,519
1996 94,891 546,751
1995 85,614 503,350
1990 66,460 260,390
1980 63,318 338,664

Year Total Violent Crime Arrests Total Property Crime Arrests
2004 590,258 1,649,825
2003 597,026 1,605,127
2002 620,510 1,613,954
2001 627,132 1,618,465
2000 625,132 1,620,928
1999 644,770 1,676,100
1998 675,900 1,805,600
1997 717,750 2,015,600
1996 729,900 2,045,600
1995 796,250 2,128,600

Sources: Crime in the United States: FBI Uniform Crime Reports 2004
(Washington, DC: US Government Printing Office, 2005),

[KeepUSfree]

Uh....that's kinda part of the point.