Causes
Of Esophageal CancerEsophageal cancer shows the most profound difference
among cancers between those countries with the highest and those with the lowest
frequency. This difference is 17-fold for mortality among
comparable populations based on geographic location alone. The U.S. is one of
the countries with the lowest occurrence rates, but at the other end of the spectrum
are Iran, Switzerland and France. The highest mortality rates from esophageal
cancer are found in China, Singapore and Puerto Rico. In the U.S. during
1996 there were 12,300 new cases (9400 men, 2900 women) and 11,200 deaths (8500
men, 2700 women) attributed to esophageal cancer (Ref.2). As can be seen
from the table above, esophageal cancer has a high mortality (=death) rate because
the death rate per year is almost reaching the amount of new cases
per year. In other words, there is a very poor cure rate for esophageal
cancer.
Occurrence and death
rates of esophageal cancer (in the U.S.) | Rate
of occurrence: | these
figures indicate a high death rate for esophageal cancer |
| 3.9 / 100,000 |
Death
rate: | | 3.4
/ 100,000 | This is a reflection of the fact
already mentioned above that esophageal cancer tends to metastasize early via
the blood stream and via lymphatic pathways. By the time the patient has symptoms
and the physician diagnoses the esophageal cancer, it is too late: the cancer
has already spread and is often a stage III or IV (see below) at the time of diagnosis.
Another peculiarity is that esophageal cancer is 3-fold more common in black
persons within the U.S. when compared to whites (the figures quoted above are
for whites). At the present time we do not know whether this is due to genetic
differences, due to life style choices or a combination of both. Causes:
Alcohol consumption as well as cigarette smoking have been linked to the development
of esophageal cancers. The higher the concentration of alcohol (like in hard liquor),
the higher the risk for cancer development. About 3% of esophageal cancers
arise from scar tissue in the esophagus from prior caustic injuries from accidental
or suicidal swallowing of lye. It often takes 40 years between injury and the
occurrence of cancer. In about 0.5 % of patients with esophageal diverticula,
pouches that often are there from birth, esophageal cancer can develop.
With exposure to cigarette smoke a phenomenon can occur where a second cancer
develops in the same region such as a head and neck cancer (1/3 of he time associated
with esophagel cancer), throat or bronchial cancer. This phenomenon is called
"field cancerization" (Ref. 1). In a condition called "achalasia"
the nerve supply in the lower esophagus is malfunctioning and this leads to impaired
motility and relaxation of the esophagus with resulting swallowing problems and
regurgitation of food. This condition typically starts between the ages of 20
and 40. As many as 20% of patients eventually develop esophageal cancer. Another
high risk setting are patients with reflux esophagitis, where acid from the stomach
irritates the lining of the lower esophagus and this can lead to a condition called
Barrett's esophagus. This is a premalignant condition where further chronic irritation
through acid reflux can lead to a type of esophageal cancer, called adenocarcinoma. There
are a number of very rare genetic conditions such as the Plummer-Vinson syndrome
where esophageal webs are found in the upper esophagus and this is associated
with iron deficiency, brittle fingernails and an enlarged spleen. These patients
are predominantly female and are at a higher risk for developing esophageal cancer.
Finally, there are many chemicals that can cause cancer apart from the
carcinogens of cigarette or pipe smoke and the toxic effects of alcohol. Several
reports have pointed out since the late 1960's that curing agents for meat and
sausages and certain cheeses, such as sodium nitrites and sodium nitrates will
be changed in the stomach into nitrosamines, which get absorbed, metabolized in
the liver and then excreted by the kidneys. These nitrosamines are powerful carcinogens
that will lead to cancer of the esophagus, stomach, liver, kidneys and bladder,
in other words whatever tissue they get in contact with. Other carcinogens such
as cigarette smoke will potentiate this cancer producing effect (Ref. 3). Beside
these factors the author points out that moldy foods, certain rare plant carcinogens
and dietary deficiencies can also lead to esophageal cancer.
Esophageal cancer prevention: Have
you checked your food labels lately? Look for nitrites and nitrates in sausages,
ham, turkey breast, meat and cheeses. You may have to ask your deli-clerk to show
you the label on the big package before they slice it for you. Many manufacturers
are aware that nitrates and nitrites are carcinogenic as they are metabolized
into nitrosamines, powerful cancer producing chemicals. Manufacturers often do
not include it in the product label . Others are oblivious to the medical literature
on this topic, possibly because of lobby groups. If you cannot find a brand that
does not contain nitrites or nitrates as preservative, then you would be better
off to cook your own meat and slice it. Your health is at stake! |
For more information on causes
of esophagus cancer see this link. |
