Jul
13
2013

Low Cost Cervical Cancer Screening

Recently a low cost screening method for cervical cancer was developed in India. About 25% of all invasive cancers of the cervix in the world are contributed from India as screening for cervical cancer is not practiced there on a large scale. Many screening methods for cervical cancer have been refined over the years as described here.

However, these screening methods are expensive.  They require a doctor who does the Pap test (or takes a swab for DNA testing), a cytological laboratory and also a gynecology service back up for positive cancer cases. In the Western world these services are in place and are responsible for improved cervical cancer survival rates.

The American Cancer Society (ACS) guidelines state that cervical cancer screening should begin 3 years after the initiation of sexual intercourse. Women should be screened every year for the first 3 years. If 3 consecutive screening results were normal, then a Pap test once every 2 or 3 years would suffice. Because of the Pap test the incidence of cervical cancer has continually dropped in the Western world as seen in this image. Compare this to the next link, which shows India as the main part of the undeveloped countries as a graph on top of the graph for cervical cancer incidence of developed countries.

With the new insight that cervical cancer is due to a chronic HPV infection, mostly due to strains 16 and 18 there are shifts in screening methods even in the Western world as DNA tests for HPV can identify a high percentage of cases that would otherwise go on to develop cancer of the cervix. However, due to cost issues with regard to DNA testing for HPV the Pap test is still the method of choice in many Western countries including the US.

Low Cost Cervical Cancer Screening

HPV16 and HPV18 were very prevalent in the cervical cancers found, not only in premalignant lesions, but also in advanced cervical cancer as this study showed. The authors concluded that vaccination with the HPV vaccine (e.g. Gardasil) would have a significant impact on the prevention of cervical cancer, particularly in a country like India where a regular screening program is not yet in place.

An inexpensive test for cervical cancer screening

In 2009 there was a publication in the New England Journal of Medicine that investigated three screening methods for cervical cancer, the familiar Pap test (cytology testing), human papilloma virus (HPV) testing and visual inspection after staining with 3-5% acetic acid. In Western medicine the Pap test is done first and if suspicious cancer cells are detected, this is followed up with colposcopy where acetic acid staining is done and a biopsy is taken from the suspicious area. The new method  of the 2009 publication for mass screening that was tested here was a single acetic acid staining and looking for suspicious areas of the cervix, which then would trigger further evaluation and treatment by the gynecologist. After this one-time test was done in 1999 the patients of this study were followed up again (10 year follow-up). The results were that direct DNA testing for HPV had resulted in a 52% reduction of deaths from cervical cancer when compared to the control group where no testing was done. The other two test methods, done as a single test (cytology testing and acetic acid visualization) did not result in reduced mortality when compared to the untreated control group after 10 years. However, a 15-year follow-up of a one-time screening with the acetic acid test showed a reduction of 31% in the cervical cancer death rate (reduction from 16.2 women per 100,000 to 11.1 women per 100,000) as reported recently at the annual meeting of the American Society for Clinical Oncology. Shastri and co-workers, the authors of this study, estimate that this would translate into prevention of 22,000 cervical cancer deaths annually in India and if instituted across the developing world it would save 73,000 lives annually.

Is cervical cancer screening effective?

A meta-analysis of several randomized studies regarding the effectiveness of cervical cancer screening in reducing mortality from invasive cervical cancer was published in May 2013 and found that cancer screening is indeed very effective.

In most studies there was a 62% to 65% reduction of mortality from invasive cervical cancer when Pap tests (cytology testing) or DNA tests for HPB were done. The protective effect from screening lasted about 5 years. However, the practice of doing Pap tests or DNA/HPB testing every 1, 2 or 3 years is safer than waiting 5 years between tests as there is a cumulative protection to the point of preventing almost 100% of cervical cancer over the years with regular testing. For India and other development countries the inexpensive visual inspection method to screen for cervical cancer after staining with 3-5% acetic acid is better than not doing any screening at all. A nurse can readily learn this type of screening and only patients with positive or questionable screening results would be referred to a treatment center.  However, if this screening method is combined with vaccinating girls with an HPV vaccine, this will add to a more complete prevention program for cervical cancer in these countries that could otherwise not afford screening. The Bill & Melinda Gates Foundation is helping to reduce the cost of the HPV vaccine to about $4.50  from about $170 in the US, which will allow mass vaccination in development countries in the near future.

What other cervical cancer prevention is available?

As pointed out earlier it is now evident that most cases of cancer of the cervix are due to chronic HPV16 and HPV18 infections. These can be acquired in the teens and linger on unnoticed within the affected cervical cells only to manifest themselves as cancer of the cervix 10 to 15 years later. This long latency period allows the physician to screen for this before it becomes invasive and is more difficult to treat. What has become more evident only in the past few years is that other human tissues can get infected with papilloma virus as well and turn cancerous over the years.

Oropharyngeal cancer, anal cancer, penile cancer, vulvar and vaginal cancer and even some forms of throat cancer and lung cancer can develop from intimate contact with a person who is HPV positive. Oral cancer is now found to be more than 70% related to HPV infection rather than caused by cigarette smoking or alcohol as in the past. Sexual practices have changed over the past decades with oral sex being more common. This can be the reason for the higher frequency of HPV caused cancers as just mentioned.

Finger pointing is not uncommon when it comes to a rational discussion of HPV transmission, but it has become apparent that males are often the ones who may be spreading HPV unknowingly through promiscuous sexual activities. Both heterosexual and homosexual activities will spread HPV. But the more promiscuous a woman is, the more she will also contribute to HPV infections in the population. When the HPV vaccines Gardasil and Cervarix were developed many religious groups have spoken out against vaccination, as this would “encourage promiscuous behavior”.  I look at this question from the point of view that lives can be saved down the road by preventing several cancers as indicated, and that is what counts on the long-term. In this context it makes a lot of sense that not only females get vaccinated, but also males to interrupt the infectious chain and this trend can now be seen as it is adopted by several jurisdictions.

Conclusion

Cervical cancer screening is still very necessary doing a Pap test or a DNA/HPV test. Screening needs to be done more often than every 5 years as pointed out. Most women need a Pap test every 2 to 3 years. HPV vaccination with Gardasil and Cervarix for boys and girls prior to sexual relations is very preventative, but still does not mean that screening should be stopped. Cervical cancer is the cancer that has the longest medical history of moving from a very prominent deadly disease (back in the 1960’s) to a cancer that can now be cured and prevented.

References

  1. Causes of cervical cancer: http://nethealthbook.com/cancer-overview/cervical-cancer/causes-cervical-cancer/
  2. HPV vaccine: http://www.mayoclinic.com/health/cervical-cancer-vaccine/WO00120
  3. Review of cervical cancer: http://www.nethealthbook.com/articles/cancer_cervicalcancer.php#topoftable

Last edited Nov. 7, 2014

Mar
10
2013

March Is Colorectal Cancer Awareness Month, So Let’s Discuss Prevention

I remember how only 40 years ago cancer of the cervix was one of the major killers for women, but with the introduction of the Pap test this has all changed.  For those women who get that screening done, there is no need for fear. The mortality rate from cervical cancer since the 1970’s has steadily decreased as shown in this link.

As far as cancer of the prostate is concerned, a lot of progress with regard to early detection has been made due to the introduction of the PSA blood test, which is used as a method of screening. As a result men are diagnosed earlier with prostate cancer resulting in more cures as the cancer found is at an earlier stage. Here is a link depicting the effect of the PSA test on mortality rates from prostate cancer in time.

March is colorectal cancer awareness month as this article explains.

The key is early detection and treatment as with any type of cancer. Specifically, with rectal and colon cancer there are mostly no symptoms, as blood in stool or any other symptoms occur only late into the disease. What we do know, however, is that there is a long latent phase where precancerous mucous membrane changes lead to polyps and these will degenerate in time into cancer of the colon or rectum.

Not everyone has the same risk of developing colon cancer or rectal cancer.  There are people with a higher rate of colorectal cancer, as they carry a susceptibility gene in their families. A healthy lifestyle can also reduce the risk of colorectal cancer.

March Is Colorectal Cancer Awareness Month, So Let’s Discuss Prevention

March Is Colorectal Cancer Awareness Month, So Let’s Discuss Prevention

It is now widely accepted that polyps are the precancerous precursors for colorectal cancer and colonoscopies done on everybody starting at age 50 (those with family risk factors much earlier) have already been shown to have decreased the frequency of the disease as the data from the CDC show. The problem is that the curves over the years shown here should have had a much steeper decline similar to the mortality rates of cervical cancer and prostate cancer shown as links above (not the shallow ones depicted in the CDC link); the incidence of colon cancer should have gone down to almost the zero point. All that has been achieved so far is a reduction of a portion of cases (those who went for colonoscopies early enough before it turned into colon cancer); this is by far not an elimination of colorectal cancer. The reason for this is the fact that in many cases people have colonoscopies too late when the polyp has already turned cancerous, or invasive colon or rectal cancer is already present at the time of the first colonoscopy.

So, designating March as colorectal awareness month makes a lot of sense to me.

I happen to come from a family where my mother died in 1980 from colon cancer at the age of 59. Because of this my doctor told me that I have a risk of about 3-fold higher than the population at large to also develop colon cancer. I have had colonoscopies since the age of 40 every 3 years. Ironically a few days ago right during the colorectal awareness month, I was getting my 9th colonoscopy. On three occasions polyps were removed, which tells me that the cancer-screening program works!

So why is it important to screen in regular intervals? One reason is that we are now exposed to more toxic chemicals in our environment and food than 100 years ago. So all cancers, but especially colorectal cancer rates have increased. We know the pathophysiology, which is the science that studies how an illness develops. We know that it takes several years between the occurrence of the first precancerous cells that form in the lining of the gut (called “mucosa”) and the formation of polyps. It takes another few years before polyps turn cancerous. This means that there is enough of a time interval to do screening. If we are not aware of this and ignore it (as unfortunately many people do), the process will run down the conveyor belt on an automatic program, which ends up in end stage colorectal cancer. The stages of colon cancer are depicted in this link.

As the table of my chapter on colon cancer staging shows, the invasive end stage colon cancer (stage IV or Duke D) has a 5-year survival rate of only 6%. Even when the cancer is limited to stage II (also called Duke stage B) there would be a 5-year survival of only 80% (see table in link).

What does screening really achieve?

On an individual basis the gastroenterologist who does the colonoscopy can screen the whole colon for premalignant polyps and remove them during the procedure.

This moves the potential cancer staging backwards to beyond any detectable cancer, as all of the potential early cancer cells would have been inside the polyp (called local “in situ” disease) and were removed by cauterizing the stalk (see above link). There is another potential factor that can help to reduce colorectal cancer incidence: Recently a connection was made between Helicobacter pylori (H. pylori) infection of the stomach and polyps in the colon as well as colon cancer. In the past several smaller studies failed to show this correlation. It took 156,269 patients in this study to show that there was a correlation. As H. pylori is being tested for and treated more and more, this will also have a positive effect on lowering the frequency of colorectal cancer.

On a population basis with mass colonoscopy screening the incidence of colorectal cancer would be reduced much faster and eventually would turn into a disease similar to cancer of the cervix, where it still matters whether you screen or not, but very few people would have to suffer from it. Here is an image from a paper (look for Fig. 2, halfway down the page) that shows that survival benefits (longer lives) are registered only after 10 years or more following colonoscopy. Every polyp that is removed  in a particular patient will ad up to the colon and rectum health of the nation at large when you sum up all of the colonoscopies done around the country year after year.  But we need a nationwide and worldwide awareness that this is something worthwhile doing for a cancer that is the third most frequent cancer in many parts of the world.

I am grateful that colonoscopy screening works, as I had polyps removed three times over a 29 year span and I did not have to go through all the surgical procedures that my mother had to endure. Had I lived 50 years earlier I may not have lived long enough to tell you how important colonoscopy screening is.

Here are the recommendations:

  1. No risk of colorectal cancer in your family : Screen once at age 50, just to make sure you are not one of the spontaneous colorectal polyp producers. If OK, screen every 10 years, if the colonoscopy is always negative.
  2. Family history of direct bloodline relative (mother, father, brother, sister had cancer of the colon or cancer of the rectum): do colonoscopies every 3 years. There may be up to 15% of missed polyps during a colonoscopy so that with the next colonoscopy there is a high likelihood that these missed polyps would still be diagnosed early enough (before they turn cancerous) and removed during this subsequent screening.
  3. There are special cases, families with genetic syndromes like the familial polyposis of the colon. In these families children need to be screened for polyps when they are young adults (from age 20 to 25 years onwards).

Don’t complain, if you belong to category 1 or 2 as it could be much worse (category 3). Cancer is serious business. Remember, March is colorectal cancer awareness month.

More information about colon cancer: http://nethealthbook.com/cancer-overview/colon-cancer/

Last updated Dec. 18, 2014

Jan
01
2005

Vaccine To Eradicate Cervical Cancer

Dr. Diane M. Harper, a lead researcher from Dartmouth Medical School in New Hampshire has called the results of a vaccination trial against the Human Papilloma Virus (HPV) “extremely exciting and encouraging”. A simple vaccination against this virus, which is the cause for cancer of the cervix, has the potential to eradicate the vast majority of cervical cancers worldwide.
The injection in the study was tested on 1,113 women between the ages 15 and 25 over an 18-month period. One hundred percent of the patients of the vaccinated group escaped persistent infection.

The protection against initial HPV- infection was at 92 %.
At this point a much larger trial is set to begin, before the vaccination can be licensed for general use. It will very likely soon be a routine vaccination for young women. If it is successful, it will be a powerful tool for prevention and will save thousands of lives that otherwise would be lost to cervical cancer. Even for those patients who dread shots, a needle prick will be a small price to pay.

Vaccine To Eradicate Cervical Cancer

Vaccine To Eradicate Cervical Cancer

More info on cervical cancer: http://nethealthbook.com/cancer-overview/cervical-cancer/

Comment on Nov. 7, 2012: In the meantime the vaccine has been introduced into the school vaccination program of many countries around the world, but mostly concentrating on the female population.  In Australia the vaccine is given to boys aged 9 to 15 and girls.  The two main brand names are Gardasil and Cervarix. Here is a detailed medical review from Great Britain.

Last edited October 27, 2014