July 4, 2008

ViziLite Plus

We didn't tough our co-blogging project Thing of Ugly at all in 2007, but Maggie found a worthy subject for a quick update.

Check out her excellent post ViziLite Plus where she ponders the information that's missing when the hard sell comes on for oral cancer screening in the dentist's chair.

I actually took the screening when they offered it to me, months ago, but Maggie is right. The statistics they give you are misleading if you're trying to use them to decide what your risk of oral cancer is.

When should you be suspicious of a medical statistic? Here is one big warning sign: statistics that tell about the population of people who already have the disease do not help you in determining your own risk. You need to know what percentage of the general population (or your particular risk group) contracts the disease. If more people asked this sort of question, like Maggie did, maybe medical professionals would be more careful in informing the public.

It's not too much to hope that the public could one day understand the concept of risk a little better. Check out Maggie's post for more details.

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Posted by James at July 4, 2008 8:39 AM
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I saw that yesterday and was going to reply but couldn't from work. I agree people whould be better at judging risk but don't think they will. Look how hard it was for Maggie to figure out and she's a smart, highly educated person. The average person just isn't going to do that.

That being said they shouldn't have to. It is up to your doctor/dentist to inform you of whether a treatment/test/drug's benefits outweigh the risks/costs. That's what you are paying them for. If your doctor isn't willing to do this you need another doctor.

Part of the problem is this may be a quick easy way for a dentist to make 20 bucks. I would wait until insurance was willing to cover it. If this test is valuable enough then they will eventually cover it since it will save them from having to pay treatment costs for cancer. That's why they'll pay for mammograms, psa tests, etc. It may take a year or two but if it's worth it it will get there. If you aren't in a high risk group I would think it wouldn't be much of a problem to wait. If you are a smoker I would guess it's worth going ahead and getting the test.

Posted by: B.O.B. (bob) at July 4, 2008 10:02 AM

Perhaps a lower place to put the bar would be to at least allow people to understand when a statistic is being misused, even if calculating risk is hard.

Also, very good point on insurance. Insurance companies actually do have people figuring out risk. It's perhaps useful to take some cues from them, even though your health is not their primary concern and they do lag behind the technology.

Posted by: James at July 4, 2008 10:35 AM

Here's a little info from the directions for use, and I have put some key wording in bold (see the DFU at http://www.vizilite.com/UserFiles/File/Single%20page%20PI9.5.2007.pdf ):

Device Description
Following the conventional manual and visual examination, ViziLite is used for the
identification, evaluation, and monitoring of oral mucosal abnormalities in a patient population at increased risk for oral cancer.

Indications for Use
The ViziLite TBlue Oral Lesion Identification and Marking
System is a three-component swab system which is indicated as anadjunct to the ViziLite examination for oral mucosa lesions for further evaluation and monitoring of lesions by physically marking lesions suspicious for cancer or precancer already differentially identified with ViziLite in a population at increased risk for oral cancer.

In the "Clinical Studies" section of the DFU, there appears to me to be a description of who is "at increased risk for oral cancer":

Clinical Studies
A clinical study was conducted with patients presenting with known oral leukoplakia or erythroleukoplakia as well as patients who previously had oral cancer and were at risk for recurrence.

Here's a link to a pilot study on ViziLite. The National Cancer Institute (NCI) has a pretty good definition of a pilot study: "The initial study examining a new method or treatment." A company does a pilot study to determine whether to go forward with a larger-scale study.

As the abstract reads, "The aim of this pilot study was to examine the efficacy of acetic acid wash and chemiluminescent light (ViziLite) in enhancing visualisation of oral mucosal white lesions, and its ability to highlight malignant and potentially malignant lesions."

Note that the patients in the study were "referred for assessment of an oral white lesion."

You can read this and other associated ViziLite trials at the NCI website here:


So, it appears to me that unless you are in a population that heightens your risk for oral cancer or you have presented with an indicator of oral cancer, you might want to save your money.

Bob expressed to me surprise at the link between HPV and oral cancer. Like I told him, think about it. If you have oral sex with someone infected with HPV, you're at risk for contracting it yourself, and HPV can cause mouth and throat cancer. This is part of the push from the gay community to get Gardasil studied and approved for men.

Posted by: Patti M. at July 4, 2008 11:56 AM

People don't get a lot of education on statistics - or don't like it, or don't absorb it, or forget it fast, who knows. That's why I hate the breast cancer campaigns that keep shouting "1 IN 8!!! 1 IN 8!!!" I see that as such a scare tactic form of marketing, and it works; I read recently that more women think breast cancer is their number one health risk than know the number health risk to women is actually heart disease.

For those who don't know, the general population risk of breast cancer, by age, from cancer.gov:
from age 30 through age 39 . . . . . . 0.43 percent (often expressed as "1 in 233")
from age 40 through age 49 . . . . . . 1.44 percent (often expressed as "1 in 69")
from age 50 through age 59 . . . . . . 2.63 percent (often expressed as "1 in 38")
from age 60 through age 69 . . . . . . 3.65 percent (often expressed as "1 in 27")
Of course any individual woman's risk would take into account additional factors like family history, etc.

ANYway - getting back on topic - I've seen signs for this at my dentist's office, along with the posters of what oral cancer signs to look for during the examination. Never got the hard sell from my denist for the Vizilight, which makes me further convinced that my dentist is a good guy :)

Posted by: mjfrombuffalo at July 4, 2008 1:26 PM

The device was cleared (approved) by FDA, so I know it isn't something some dude made in his basement and is selling from the back of his Chevy van with ball fringe curtains in the heart-shaped windows.

I'm sure this is a good diagnostic tool when used for the appropriate patient population and, as with any treatment, appropriate use is key.

Posted by: Patti M. at July 4, 2008 1:36 PM

Thank you for the information from Vizilite, Patti.

I think what the "doctor" on the Fox news video says really sums up why people pay for this, "better be safe than sorry, right?"

Similar to why people will buy a lottery ticket, "if I don't play, I can't win," or "at least I have a chance." People understand "chance" to be about 50/50, or at least something a lot more even than the actual chance of winning the lottery. (Every time I go into the local convenience store I'm tempted to thank people for buying lottery tickets and keeping my taxes low. Really tempted.)

And of course nobody wants cancer. But would you have to get this screening every year? Would you have to pay out of pocket every year? If I had it two days ago, that wouldn't make me feel confident that next year I wouldn't have lesions.

I had the HPV test, even though I might have had to pay for it (I didn't), not because I'm in a particularly high-risk group, but because my doctor told me I could skip every other pap smear if I tested negative. And if I had tested positive, then I'd know more about my risk for cervical cancer.

Insurance companies treat us as statistics. I imagine we like that when it keeps our premiums low, and we don't like that when it means they won't pay for a test that will make us feel better about not having a particular cancer. But as you all have pointed out, it gives you a good indicator of your risk.

Posted by: Maggie at July 5, 2008 8:16 AM

At first, when I read your gyno said you could skip an annual Pap if you tested negative for HPV, I winced. Then I went to Medline Plus, run by the National Library of Medicine, and I read this:


Women: Pelvic exam and Pap smear:

* Women should have a yearly pelvic exam and Pap smear done to check for cervical cancer and other disorders.

* If your Pap smears have been negative for 3 years in a row, your doctor may tell you that you only need a Pap smear to every 2 - 3 years.

* Women who have had a total hysterectomy (uterus or cervix removed) may choose not to have Pap smears.

* If you are over 70 and your Pap smear has been normal for 10 years, or if your test results have been normal for 3 years in a row, you may choose not to have any more Pap smears.

Thanks to your post, I'm going to ask my gyno this year if I really need that Pap. Thanks, Maggie.

Posted by: Patti M. at July 5, 2008 9:38 AM

I should have written "if I tested negative for HPV and have had normal paps." He stressed to me that you can't skip the pelvic exam, just the pap smear.

Posted by: Maggie at July 5, 2008 1:00 PM

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