Marijuana Smokers Have Higher Incidence of Bladder Cancer

[Guest guest]

Category: Urology/Nephrology News

Article 26 Jan 2006 - 20:00pm (UK)

 

 

 

 

 

 

Smoking marijuana appears to be a risk factor for bladder cancer and

may even contribute to younger people getting the disease,

researchers say.

 

Smoking cigarettes is the major risk factor for bladder cancer, which

is most common among people age 60 and older, says Dr. Martha Terris,

urologist at the Medical College of Georgia and Veterans Affairs

Medical Center in Augusta.

 

But a study of younger patients - 52 men age 44 to 60 - with

transitional cell bladder cancer at VA hospitals in Augusta and Palo

Alto, Calif., showed that 88.5 percent had a history of smoking

marijuana, says Dr. Terris, senior author on the study published in

the January issue of Urology.

 

Nearly 31 percent of the cancer patients still smoked marijuana,

compared to 20 percent of those in an age-matched control group. " We

noticed several younger patients who had developed transitional cell

carcinoma were similar in that they all shared a history of marijuana

smoking, " Dr. Terris says. " The literature has suggesed that

marijuana-smoking increases the risk of head and neck cancer and lung

malignancies, and that these tumors tend to develop earlier and

behave more aggressively in marijuana smokers. "

 

That prompted physicians at the VA hospitals affiliated with Stanford

University Medical Center and MCG to look at marijuana use as well as

exposure to other carcinogens, including tobacco, radiation, Agent

Orange, smoked or processed meats and synthetic dyes used in the

textile industry, in their patients. Serving as controls were 104

patients seeking urology care at the VA hospitals for reasons other

than bladder cancer.

 

Bladder cancer patients and controls had similar rates of exposure to

all the risk factors except marijuana. In fact, the study indicates

smoking marijuana may be as bad or worse than cigarette smoking as a

risk factor for bladder cancer.

 

" Marijuana-smoking might be an even more potent stimulant of

malignant transformation in transitional epithelium than tobacco

smoking, " they write, noting that marijuana metabolites have a half-

life in the urine about five times greater than nicotine metabolites.

Studies of delta-9-tetrahydrocannabinol, or THC, the main

psychoactive substance in marijuana, have demonstrated both anti-

tumor and tumor-promoting properties. Either way, THC hangs around a

long time in the bladder and urine.

 

Marijuana smoke also has many of the same carcinogen-containing tars

as cigarettes and may get even more into the body because marijuana

cigarettes are unfiltered and users tend to hold the smoke in their

lungs for prolonged periods, researchers say.

 

The combination of smoking cigarettes and marijuana may have an

unfortunate synergy. " The differences and interactions between

marijuana and tobacco use also merit further scrutiny, " they write.

Also, larger-scale epidemiologic and basic science studies are needed

to confirm the role of marijuana use in development of bladder

cancer. For now, when doctors find blood in a young patient's urine

sample, they may want to include questions about marijuana use in

their follow-up and more strongly consider bladder cancer as a cause,

says Dr. Terris.

 

And, bladder cancer patients considering marijuana to treat

chemotherapy side effects, may want to reconsider. " If they are

getting chemotherapy for their bladder cancer and smoking marijuana

to increase their appetite, they may be undoing the benefits of

chemotherapy, " she says.

 

She noted it is likely that, as with cigarettes, risks of marijuana-

smoking diminish after patients stop but never go away. " The safest

move is to never start smoking anything, " she says.

 

The Medical College of Georgia is the state's health sciences

university and includes the Schools of Allied Health Sciences,

Dentistry, Graduate Studies, Medicine and Nursing. MCG is a unit of

the University System of Georgia and an equal opportunity

institution. http://www.mcg.edu