Selenium Shows Promise

[daw]

Selenomethionine May Protect Against Esophageal Cancer

NEW YORK (Reuters Health) Oct 05 - Selenomethionine treatment of certain high-risk patients can protect against the development of esophageal squamous cell cancer (ESCC), according to a report in the September issue of Gastroenterology.

Selenium compounds and COX-2 inhibitors have shown potential chemopreventive effects on esophageal carcinogenesis in previous observational studies, the authors point out, but neither has been evaluated directly in ESCC chemoprevention trials.

Dr. Paul J. Limburg from Mayo Clinic College of Medicine, Rochester, Minnesota and colleagues tested the chemoprevention potential of selenomethionine (a synthetic form of organic selenium) and celecoxib (a selective inhibitor of COX-2) in 238 asymptomatic adults with histologically confirmed mild or moderate esophageal squamous dysplasia.

In the overall analysis, neither selenomethionine nor celecoxib significantly changed the dysplasia grade during the course of the trial. However, patients treated with selenomethionine showed a trend toward increased regression and decreased progression, the report indicates, but no such trend was seen with celecoxib treatment.

In a secondary, stratified analysis, treatment of 115 patients with mild dysplasia with selenomethionine was associated with nearly a doubling of the regression rate and halving of the dysplasia progression rate, compared with placebo. No apparent chemopreventive effect was seen in the 123 patients with moderate dysplasia.

The authors conclude that use of celecoxib appears to lack promise but "our data support further pursuit of selenium compounds as potential ESCC chemopreventive agents, particularly among subjects with early premalignant disease."

Gastroenterology 2005;129:863-873.

[james1]

Is there any indication of the selenium dosage used in this trial?

The pills at the health food store contain 200 mcg organic selenium - which is about 200% of the RDA. I spoke with a natural pathic doctor and he recommended 300 mcg/day, said selenium becomes toxic above 900 mcg/day.

james

[tricia]

Hi James :) I read this study several places on the internet and saw nothing about dosages. Remember too, this study is on squamous cell esophageal cancer .Squamous cell is associated with smoking ,drinking and infection with the human papillomavirus . There are 2 main types of esophageal cancer

The esophageal cancer thought to be associated with Barrett's is adenocarcinoma.

Don't know if the selinium would be benificial in protecting against adenocarcinoma too.

[james1]

Well, from what I read of the abstract posted the study is not on squamous cell carcinoma , rather squamous cell dysplasia - using selenium to treat squamous cell dysplasia and thus preventing the carcinogenesis (neoplasia) of the dysplastic squamous cells. Squamous cell displasia can undergo carcinogenesis (NEOPLASIA) anywhere along the esophagus. Barretts is squamous cell dysplasia - a result of normal squamous cells that have changed (metaplasia) and then become abnormal (dysplasia).

As you already know, Adenocarcinoma arises (in the lower esophagus)instead of squamous cell carcinoma because the normal squamous cells of the lower esophagus are changed to abnormal intestinal epithelium (as you know, this does not occur in the upper esophagus). These cells did start out as normal squamous cells, so if you can stop the progression of squamous cell dysplasia in the upper esophagus, hopefully you can halt its progression in the lower esophagus, i.e., halt the progression of Barrett's Esophagus.

Selenium is already established as having an anti-cancer mechanism - I don't think it would do much harm in taking it as a theraputic agent (<900mcg/day), even though it hasn't been shown to specifically halt Barretts progression....and I don't want to wait to find out since my dx is equivocal for Barretts.

james

[daw]

Hi Tricia and James,
I remember reading about the use of Selenium as a chemopreventive measure for people with Barrett's.
"Selenium, a trace mineral found in various foods and nutritional supplements, may inhibit progression toward esophageal cancer among people with Barrett's esophagus. Barrett's esophagus is a precancerous condition that affects an estimated 1 million to 2 million Americans. Fred Hutchinson Cancer Research Center researchers studied the relationship between levels of selenium in the blood and changes in the lining of the esophagus that represent advancement toward cancer. Researchers found that Barrett's patients with low selenium levels had a two- to three-fold greater risk of advanced precancerous changes than patients with selenium levels in the middle or high end of the normal range. The study is published in the Journal of the National Cancer Institute."

I also know it is being looked at with colon, lung and prostate cancers too. Aside from oxidative stress causing cancers (selenium is an antioxident) there is also a connection with the P53 gene (seen in Barrett's).

For those with Barrett's, I think it's a good idea to discuss selenium use with their doctors. Currently 70mcg is considered 100% RDA. I've read where 200mcg can be used as a preventative for cancers.

"High blood levels of selenium (greater than 100 μg/dL) can result in a condition called selenosis [62]. Symptoms of selenosis include gastrointestinal upsets, hair loss, white blotchy nails, garlic breath odor, fatigue, irritability, and mild nerve damage [2].

Selenium toxicity is rare in the U.S. The few reported cases have been associated with industrial accidents and a manufacturing error that led to an excessively high dose of selenium in a supplement [63,64]. The Institute of Medicine of the National Academy of Sciences has set a tolerable upper intake level (UL) for selenium at 400 micrograms per day for adults to prevent the risk of developing selenosis [12]."
http://ods.od.nih.gov/factsheets/selenium.asp

[tricia]

Hi James and Daw :) Even though the study is definately on squamous cell carcinoma , it's mute .... as Daw pointed out, there is a beleived connection to low selinium and increased cancer risks with certain cancers. Some research indeed suggests that low blood levels of selenium are a risk factor for progression of Barrett's esophagus.

My understanding though, is that low levels of selinium is more common in Asia , and rare in North America , because our soil is so rich in this mineral . And we get a lot from meat, especially beef. Don't forget brazil nuts too . Just one ounce of brazil nuts has 1200 times the RDA.

Why don't they just test people via blood or toenail clippings?

I used to take selinium myself a few years ago, when the talk first came out about it reducing certain cancers by 50 percent. The American cancer society presently reccomends no more than 200 micrograms per day

But then i began reading about a number of terrible diseases in which people are found to have HIGH levels of selinium , ALS ( Lou Gehrig's disease) for one, .... so i decided to stop . It's kind of a darned if you do ...and darned if you don't kind of thing. Sometimes you don't know if you are doing more harm than good...

[daw]

....It's kind of a darned if you do ...and darned if you don't kind of thing. Sometimes you don't know if you are doing more harm than good...
Unfortunately this is true of many supplements. Look at Vitamin E and C. People were popping it like candy...and still are in certain situations. Also, as my primary likes to point out, even if it doesn't harm you, in many cases, you end up throwing your money away. Still it's hard to ignore new data especially when you are dealing with specific diseases and sometimes have seen your relatives succumb. As an overall preventative....moderation is the key.

[james1]

Hi James and Daw :) Even though the study is definately on squamous cell carcinoma
..

How can the study be on squamous cell carcinoma when the subjects don't have cancer. It's a study to see if squamous cell dysplasia can be prevented from becoming squamous cell neoplasia......................

[daw]

James, I think squamous cell dyplasia is what may lead to squamous cell carcinoma in the middle to upper part of the esophagus. Barrett's esophagus is a condition in which the normal squamous epithelium of the distal esophagus has been replaced by an abnormal red columnar epithelium called specialized intestinal metaplasia. When dysplasia is seen here it can lead to adenocarcinoma. The study only deals with squamous cell dysplasia and not dysplasia of the specialized intestinal cells.

[james1]

I never said it did dealt with intestinal epithelium (read my second post).

I know there is a difference between what occurs in the upper and lower esophagus (read my second post). My point is that if selenium can prevent dyplasia from progressing to cancer in a specific tissure then there may be hope that it will do this in general for any form of dysplasia.

[daw]

My point is that if selenium can prevent dyplasia from progressing to cancer in a specific tissure then there may be hope that it will do this in general for any form of dysplasia.
I definitely agree

[tricia]

Hi :) Oh i agree too James . Wouldn't that be true with all squamous cell dysplasia ? , it may lower the risks of skin cancer and cervical cancer etc too. But i also agree with Daw that moderation of these supplements are key , until more is known regarding the flip side.

Squamous cell cancer progresses through a progressive sequence from mild to severe dysplasia, carcinoma in situ and, then invasive carcinoma.

I read the full study and it is a study of a town in China, where Squamous cell cancer is prevalent. It is also very prevelant in Iran, South Africa, Uruguay, France and Italy.

In the intro, they talk about Squamous cell being more prevelent world wide . Many don't realize that more than 90% of all esophageal cancers worldwide are actually Squamous cell esophageal cancer, and adenocarcinomas make up less than 10 percent of esophageal cancers , although adenocarcinomas are far more prevalent in North America.