Definition of "Pap smear"

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Pap smear (short for Papanicolaou, also known as Cervical smear) is the screening for potentially pre-cancerous and cancerous processes in the cervix (i.e. opening of the uterus or womb), i.e. cervical cancer. As a screen, unusual findings are followed by more specific Dx, and if warranted, intervention to prevent progression to cervical cancer. Examples of a pap test include ThinPrep Pap Test.


Source: Hologic

Patient information

What is a pap smear?
It is used to check for a possibility of cervical cancer.

Wait... what is the cervix?
It is the opening to the uterus (which is also known as the womb).

What do you mean by a "screening test"?
It means if it comes back negative, you most probably don't have it. But if it comes back positive... you need to do more tests, to confirm whether you have it or not!

So if it comes back positive does that mean I have cancer :'(??!
No. We are only testing for abnormal cells on the pap smear. It increases the likelihood of cancer, but it isn't cancer. Even HSIL/CIN 3 is still only considered "carcinoma in situ", a "pre-cancer". So it's not cancer , but just cell changes caused by HPV infection.

HPV DNA testing is a screen for the virus causing abnormal cells on the cervix, and can be done alongside the pap test.

Patient information

Wait... why have 2 screens? Why not just use 1?
Because they test different things. Pap smear tests for abnormal cells. HPV tests for the HPV virus - which causes the abnormal cells.

Sorry, what was HPV again ?
It's the virus that is implicated in 70% of cervical cancers.

Pathophysiology
  • Human papillomavirus (HPV) is a sexually transmitted virus that infects skin or mucous membranes, and is usually subclinical, causing no Sx. It can however, cause warts or papillomas (i.e. benign epithelial tumor), and even cancers of the cervix, vulva, vagina, throat, penis, and anus
  • There are more than 40 types of HPV transmitted typically through sexual contact, and infects the anogenital region, but HPV16 and 18 are implicated in 70% of cervical cancer cases
  • High risk HPV types are different from the ones that cause skin warts, and may progress to cancer
  • Most infections do not cause disease
  • 70% of clinical HPV infections regress to sub-clinical in 1 year
  • In 7% of women, subclinical infection persists, and there is high risk of developing precancerous lesions which can progress to invasive cancer
Purpose
  • Early detection of pre-cancerous and cancerous processes in the endocervical canal of the female reproductive system
  • The test may also detect infections and abnormalities in the endocervix and endometrium, but is not designed to do so
Indications
  • Pap smear is recommended from 18yo until 70yo, every 2 years
  • Abnormal results should be followed up by a repeat test in 6-12 months
  • If the Pt is menstruating heavily, they should use the liquid-based cytology method, as RBC's can obscure the cervical cells on a traditional slide; cf with liquid technology, RBC's can be filtered out
  • Pap smears CAN be undertaken during pregnancy, ideally <24 weeks. There is no evidence it causes any problems in pregnancy. However, cytobrushes should NOT be used on pregnant women
  • To be viable, the patient should NOT be menstruating and had NOT used a vaginal contraceptive in the prior 24-48 hours
  • Because of the preoccupation with pregnancy, you can opt to do the pap smear instead at the 6-8 week postnatal check
  • Cytobrushes should be used in all women >40yo

Source: NSW Health

Patient information

Who gets papsmears? Do men do them?
No , because men don't have cervixes!! Because papsmears test for the HPV virus which is sexually transmitted, it is done when a woman becomes sexually active AND is sexually active.

So if you're not sexually active, you don't need to do them?
Yeaaap !

A "complete hysterectomy" is where the uterus is removed with the cervix, right? Well, if you do that, do you still need the papsmear given you don't have a cervix anymore??!
It depends. In practice, most women continue to have papsmears, and they should particularly if they are at high risk, such as having had the hysterectomy done for a cancerous condition. But if they're not high risk, they don't have to.

Method
  • Opening the vaginal canal with a speculum, then collecting epithelial cells from the outer opening of the cervix, at the transformation/transitional zone (i.e. the squamo-columnar junction of the cervix between the ectocervix and endocervix). There are 2 methods of collection, of which either can be used:
    • Conventional pap, where samples are obtained using the conventional spatula, placed against the face of the cervix, and rotate 360 degrees. Then, the cylindrical endobrush is placed into the cervical os, and rotated 360 degrees. The specimen is then smeared on to a microscope glass slide by rolling or twisting the spatula/brush on to the slide. Fixitive is then applied
    • Liquid based cytology, where samples are obtained using the arrow-shaped broom brush, rotating the brush several times. Disconnect the brush tip, and suspend it in a bottle of preservative
  • Squamous cells are examined under a microscope to look for abnormal, potentially pre-cancerous changes called cervical intraepithelial neoplasia (CIN), caused by HPV. CIN involves dysplasia (abnormal growth) of squamous cells on the epithelium (surface) of the cervix. Most CIN remains stable or is eliminated by the immune system without intervention. However, a small proportion progress to cervical cancer, usually cervical SCC if untreated. An alternative system used to describe abnormalities is the SIL (squamous intraepithelial lesion) system. Squamous cell abnormalities include:
CIN SIL  
Normal cervical epithelium
ASC-US (atypical squamous cells of undetermined significance)  
ASC-H (atypical squamous cells of High grade significance)  
CIN 1 LSIL (low-grade squamous intraepithelial lesion) Involves mild dysplasia (abnormal cell growth), confined to the basal 1/3rd of the epithelium. It can usually be cleared by the immune response, but may take several years
CIN 2 HSIL (high-grade squamous intraepithelial lesion) Involves moderate dysplasia confined to the basal 2/3rd of the epithelium
CIN 3 (aka cervical carcinoma in situ) Involves severe dysplasia, that spans more than 2/3rds of the epithelium, and involves the full thickness
SCC (squamous cell carcinoma)  
  • Glandular epithelial cell abnormalities:
    • Adenocarcinoma
    • AGC-NOS (atypical glandular cells not otherwise specified, formerly atypical glandular cells of undetermined significance, AGUS)
  • Abnormal findings are often followed up by more sensitive Dx procedures, and if warranted, interventions that aim to prevent progression to cervical cancer
  • Vault smear is where the pap smear is taken from the top of the vagina, in women who've had their cervix removed, to test for cancer of the vagina

Patient information

So what does the pap smear involve?
A swab is inserted into the vagina, twisted around the walls of walls, to get a sample of cells on to the swab. That swab is then tested.

Side effects
  • Can cause spotting and minor bleeding following the pap smear
Follow up
  • LSIL (low grade abnormal) or CIN 1, will be monitored w/ a repeat pap smear in 1 year. (Usually papsmears are done every 2 years.) Notably, NO colposcopy is necessary. If the repeat pap smear STILL shows low-grade, it is referred for colposcopy. If the pap smear returns normal, a pap smear will be repeated at 12 months, which if normal again, will revert to the 2 year cycle
  • HSIL (high grade abnormal) or CIN 2/3, will be referred to colposcopy, and biopsy/Tx as required. Pap smear and colposcopy will be repeated in 4-6 mo after Tx. Pap smear and HPV test will be repeated in 12 mo after Tx twice, which if 2 in a row are negative, return to normal 2 year screening
  • Colposcopy in pregnancy is safe

Source: CancerScreening (page 26)

Patient information

OK, papsmear has been done. it's come back "low grade abnormal". What to do?
First of all, understand that what's come back positive is not a "cancer". It's a viral infection that's been detected. Now because it's "low grade", most likely it will clear within 1-2 years, so we just leave it.

How about if it's "high grade"? Or... the same case from before, but now I've done a repeat papsmear, and it's come back positive... again ?!
You will be referred for colposcopy.

Col... what? Coles supermarkets ?
Colposcopy . It's where a colposcope is used to magnify the cervix. We then use acetic acid, which should turn abnormal areas white. If that fails, we use Lugol's idone, which should turn abnormal areas yellow.

OK, "abnormal areas detected". What next ?
We loop it and take that biopsied loop. We can also freeze it, but that destroys the sample, so we prefer to loop it. If it's severe, we want to take it out PLUS a margin around it, done so in the form of a cone-shaped wedge, which is called a "cone biopsy".

That "looping" sounds a bit like a good ole Western... yeeeehah ! Where we loop it and yank the ole fella out!
True indeed.

Does the colposcopy have any side effects?
It's not uncommon to feel discomfort for a short time. You might also get some "spotting" of blood aftewards.

Now that I've been treated, anything else I need to know?
Screening now changes for you. We repeat a papsmear in 6 months, and from 12 months both the papsmear and HPV DNA test, and if they are negative for 2 years in a row, you return back to the normal schedule of screening every 3 years.

Epidemiology
  • 80% of people will be infected with HPV some time in their lives, and may not even know about it
See also
  • Cervical cancer (for more information about follow up)
  • Pelvic exam (method for taking the swab)
  • Colposcopy

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Definition of Pap smear | Autoprac


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