I should clarify that I am not a doctor. ;-) Sorry, I never noticed that the first time around.
It is frustrating that smears are not 100% accurate, which is why it is so important to keep up with regular screenings (in case there is a false negative). Cervical cancer tends to be very slow growing so the chances are if an area of dysplasia was missed during sampling one year then likley it will be caught the next time before it has an opportunity to become cancer - or that is the hope.There is always a chance for human error, either when obtaining the sample or when examining the sample too. Recently, the HPV test has been used in conjunction with the pap smear (for women over 30). That way, if a woman is testing positive for an active high risk strain(s) of HPV (which causes dysplasia/cancer) for a period of 6 months or more she should be referred for a colopscopy to see if there is a small area dysplasia that the pap smear is missing.
Thanks so much Dr.
I feel much better now. However, there still one question to ask.
If there is a 40% false negative for the pap smear...it seems it would not be a good screening tests. Are there any better? Probabilites are additive.....the more pap smears we do the lower de false negative...am i right?
Thank you very much for taking your time to answer these question.
I really apreciate it.
Unfortunately, even though you have been tested there isn't an FDA approved HPV test for men so this isn't something you would have been tested for. You are not alone in not knowing you had the virus, 80% of the population will have an active infection of HPV by the time they are 50 but the majority of people will never have any idea they have it. HPV has an ability to lay dormant for years (over 20 even) before becomming active, if it ever does. HPV is incredibly common in today's society because people are unknowingly transmitting the virus to their partners, for most there are no ill-effects or symptoms, not to mention the fact that it can be transmitted through simple skin to skin (genital) contact and condoms are only 70% effective.
The digiene test is currently the only FDA approved HPV test. It can only detect an active strain(s) of HPV (if the virus is dormant at the time of testing it will not be detected). If there is an active HPV infection, test can tell you only if the strain(s) are of the low risk category (wart causing), high risk category (potential to cause cancer) or both. Strains of low risk HPV are wart causing and are not resposible for HPV related cancers. Having a high risk strain(s) of HPV does not mean she will develop cancer, most women will clear it (push it into dormancy) without any symptoms or ill effects. For a FEW women, a persistent HR-HPV infection can go on to develop cervical dysplasia. There are different levels of dysplasia, the majority of mild dysplasias (CIN1) will revert on their own without any medical intervention.Only about 5% of CIN2 (moderate dysplasia) if left will go on to become cervical cancer and about 12% of severe dysplasia (CIN3/CIS (carcinoma in situ)) will if left will go on to develop into cervical cancer. The problem is that our medical system does not have the ability to know which dysplasias will progress and which ones won't so typically, moderate and severe dysplasia is removed. It is very easily treated and most women will only require 1 treatment, however due to HPV's ability to go from a dormant state to active as well as it's abiltiy to affect the vagina and vulva it is important to continue with regular paps and HPV tests for life. Also, smears are not 100% accurate, which is another reason it is important to keep up with regular screenings. Some research indicates that as many as 40% of smears are a false negative! Pap smears are only a screening test for abnormalitiies, a colopscopy gives a more difinite diagnosis. If a women tests positive for a HR-HPV infection for longer than 6 months but pap smears are clear she should be referred for a colopscopy in case the pap is missing an area of dysplasia.
So the overall percentage of women developing cervical, vulvar or vaginal cancer is very low because only a small number of women will actually develop dysplasia and only a small percentage of those will actually progress if left untreated but because no one knows who will progress and who won't it is important to keep up with tests and screening.