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All Posts Tagged: cancer care

Top 6 Carcinogenic Food Contaminants

Cancer is on the rise. The number of new cancer cases in Canada is expected to rise about 40% in the next 15 years, according to a new report – Canadian Cancer Statistics 2015 – released by the Canadian Cancer Society. Almost all cancer deaths in Canada (96%) will occur in people over the age of 50, and most (62%) deaths will occur in those aged 70 and over.

Many people worry that substances or exposures in their environment may cause cancer. Food is one of them. We eat (at least) 3 times a day and what we eat has tremendous impact on our health.

But let first define what a carcinogen is.

Cancer is caused by changes in a cell’s DNA – its genetic “blueprint.” Some of these changes may be inherited from our parents. Others may be caused by outside exposures, which are often referred to as environmental factors. Environmental factors can include a wide range of exposures, such as:

  • Lifestyle factors (nutrition, tobacco use, physical activity, etc.)
  • Naturally occurring exposures (ultraviolet light, radon gas, infectious agents, etc.)
  • Medical treatments (radiation and medicines including chemotherapy, hormone drugs, drugs that suppress the immune system, etc.)
  • Household exposures
  • Workplace exposures
  • Pollution

Substances and exposures that can lead to cancer are called carcinogens. Some carcinogens do not affect DNA directly, but lead to cancer in other ways. For example, they may cause cells to divide at a faster than normal rate, which could increase the chances that DNA changes will occur.

Carcinogens do not cause cancer in every case, all the time. Substances labeled as carcinogens may have different levels of cancer-causing potential. Some may cause cancer only after prolonged, high levels of exposure (“the dose makes the poison”). And for any particular person, the risk of developing cancer depends on many factors, including how they are exposed to a carcinogen, the length and intensity of the exposure, and the person’s genetic makeup.

The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). One of its major goals is to identify causes of cancer. The most widely used system for classifying carcinogens comes from the IARC. In the past 30 years, the IARC has evaluated the cancer-causing potential of more than 900 likely candidates, placing them into one of the following groups:

Group 1: Carcinogenic to humans

Group 2A: Probably carcinogenic to humans

Group 2B: Possibly carcinogenic to humans

Group 3: Unclassifiable as to carcinogenicity in humans

Group 4: Probably not carcinogenic to humans

Perhaps not surprisingly, based on how hard it can be to test these candidate carcinogens (who would want to be voluntarily subjected to carcinogens?), most are listed as being of probable, possible, or unknown risk. Only a little over 100 are classified as “carcinogenic to humans.”

Here is my list of the worst carcinogenic foods (contaminants).

A special note here, in case it wasn’t clear by now: food itself, in its natural state, is NOT carcinogenic. It is the process of preparing the food, the things we add to the food, we spray the food with, the way we preserve or “enhance” the food that will make the altered food be considered carcinogenic.

  • Processed meats: Most processed meat products, including lunch meats, bacon, sausage, and hot dogs, contain chemical preservatives that make them appear fresh, tastier and appealing, but that can also cause cancer. Both sodium nitrite and sodium nitrate have been linked to significantly increasing the risk of colon and other forms of cancer, so be sure to choose only uncured meat products made without nitrates, and preferably from grass-fed sources. (Group 1)

  • Microwave Popcorn: From the chemically-lined bag to the actual contents, microwave popcorn is at the center of lung cancer debates around the world. Not only are the kernels and oil likely GMO (which the manufacturer does not have to disclose) , the fumes released from artificial butter flavoring contain diacetyl, which is toxic to humans. Make your own organic popcorn the old-fashioned way – air popped – it tastes better, doesn’t release toxic fumes, and is a healthier choice for you. (Group 1)

  • Alcoholic beverages: all types of alcohol (fermented and those further distilled) can cause cancer in humans. Animal studies have not convincingly demonstrated that ethanol itself is carcinogenic leading to the hypothesis that other contaminants in alcoholic beverages or ethanol metabolites (acetaldehyde) are responsible for these effects. This is true only for heavy alcohol consumption (heavy drinkers). (Group 1)
  • Salted fish: This is produced in several parts of Asia using a method that appears to result in the production of carcinogenic by-products. These foods can be very high in nitrates and nitrites, which react with protein to form nitrosamines. (Group 1)

  • Pickled vegetables: They have been studied for their association with cancer mainly in Asia and especially in China. The pickling process is different from that used in many parts of the world and uses no salt or vinegar. Instead it relies on natural fermentation and can lead to contamination with mold. (Group 2B)

  • Genetically Modified Foods (GMOs): The rapidly growing industry of genetically modified crops are infiltrating our food supply at an alarming rate. More than 90% of our corn and soy are now genetically modified. The current research on the health risks of GMOs is inconclusive. In other words, researchers cannot confirm whether or not GMOs increase cancer risks. Yes still, IARC has recently labelled the corn or soy sprayed with Roundup (the active ingredient: glyphosate) as probably carcinogenic to humans. (Group 2A)

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Blood tests for cancer

 I am writing this article to answer a question I get from some of my patients about blood tests for cancer. Is there any reliable blood test to detect cancer? Is usually what I am being asked once in a while by my patients.

To answer this question I need first to introduce the notion of Tumor Markers.

These are substances that are produced by the cancerous cells or by the other cells (usually neighboring cells) in the body in response to the detection of cancer or other benign (non-cancerous) conditions.

A tumor is by the definition any abnormal growth of cells, a mass of cells; even a collection of fluid would qualify as a tumor in the world of pathology. Tumors could be benign (not dangerous per se) and malignant (a threatening type of tumor). Also used, there is the term neoplasm, which is another way of saying tumor, in a more academic fashion.

Stages of growth of a tumor

Now, when these cells start to multiply without control, the mass itself starts to produce some chemicals that are called tumor markers. Most tumor markers are made by normal cells as well as by cancer cells. Most of the time, they are produced at a higher number in cancerous conditions. These substances can be mostly found in the blood, but also they show up in urine, stool, tumor tissues or other tissues or bodily fluids of patients with cancer.

To date, based on the listing from National Cancer Institute (USA) website, there are more than 30 tumor markers that are used in clinical care. Some are associated with only one type of cancer, others are associated with two or more cancer types. There is no “universal” tumor marker that can detect any type of cancer. So far. Let’s hope that medicine and oncology with all the grants and pharmaceutical power behind it will find this universal marker in the near future.

The problem with these tumor markers is that sometimes, benign tumors can cause the levels of some tumor markers to increase too. This is a serious limitation to which oncology didn’t find an answer yet. On top of that, tumor markers have not been identified for every type of cancer. I mean, simply put it, there is cancers that do not have tumor markers, do not have something specific to be identified and measured. Cancer is a tricky bastard that is.

Because of these things, tumor markers cannot be used alone to diagnose cancer. They are combined with other tests, of which the BIOPSY is the gold standard in oncology (a pathologist examines the biopsied cells in the lab). Seeing is believing here.

The most common blood tests used in screening for cancer and showed to reduce the cancer deaths are:

  • Alpha-fetoprotein blood test

This test is sometimes used, along with ultrasound of the liver, to try to detect liver cancer early in people at high risk of the disease.

  • CA-125 test

This blood test, which is often done together with a transvaginal ultrasound, may be used to try to detect ovarian cancer early, especially in women with an increased risk of the disease.

  • PSA test

This blood test, which is often done along with a digital rectal exam, is able to detect prostate cancer at an early stage. However, expert groups no longer recommend routine PSA testing for most men because studies have shown that it has little or no effect on prostate cancer deaths and leads to overdiagnosis and overtreatment.

  • High-sensitivity Fecal Occult Blood Test (FOBT)

This test has been shown to reduce deaths from colorectal cancer. Colonoscopy and sigmoidoscopy are also done concurrently here and help prevent colorectal cancer because they can detect abnormal colon growths (polyps) that can be removed before they develop into cancer.

  • Calcitonin

It is a blood test used to aid in diagnosis, check whether treatment is working, and assess recurrence for medullary thyroid cancer.

  • Lactate dehydrogenase

This test is used to assess stage, prognosis, and response to treatment for tumors like: Germ cell tumors, lymphoma, leukemia, melanoma, and neuroblastoma.

So, unfortunately, the general answer to the question that prompted this article is NO. There are no reliable blood tests that will detect cancer by themselves. There are tests that will raise the alarm for malignancy but these tests are usually done after you have symptoms or are done for screening if you are a high-risk patient for a specific cancer due to your family history (someone in your family died of some cancer at an early age). The symptoms, prior risk, combined with tests (blood or genetic) and imaging will complete the picture for a doctor and a diagnosis will be made and provided.

One word about the genetic testing.

This seems to be the future of cancer screening. Genetic-based testing can tell an individual about their predisposition for certain types of cancer as well act as a tool for the early detection of cancer. These tests are much more accurate than the older generation of cancer markers.

 

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