Cervical Cancer Screening with PAP Smears and HPV Testing
The Importance of Cervical Cancer Screening:
Cervical Cancer is one of the important causes of mortality in Indian Women. It is the 3rd most frequent cancer in the world.
This is in spite of it being a slowly advancing disease. This means you can screen for the same. Screening is a vital part of detecting cervical cancer early. This allows for the appropriate treatment at the right time.
In the Cervix, there is a junction known as the squamo-columnar Junction. This is an area of active division of cells.
At Puberty, this area expands into the mucus-secreting region giving a “Transformation Zone”.
What causes Cervical Cancer?
It is a Sexually Transmitted Disease.
Both Types of cervical cancer(Adeno and Squamous) are related to infection with Human Papilloma Virus(HPV). The chief culprits are HPV types 16 & 18.
Smoking and Low Vitamin A are Cofactors.
What are the Types of Cervical Cancer?
Squamous Cell(SCC) is the commonest type(80%)
Adenocarcinoma accounts for 15%
Adenosquamous Carcinoma accounts for 3-5%
There are a few different types of carcinomas but these are unusual.
How does HPV cause Cervical Cancer?
HPV(Human Papilloma Virus) infection may lead to abnormalities in the “Transformation Zone”. Over a Period of Time, these abnormalities can give rise to “Dysplasia”. This means cells which are abnormal for a particular region of the body. This abnormality is of different degrees. All Types of Dysplasia need observation and if required, treatment. Not all women with HPV will develop Cervical Dysplasia.
Types of Cervical Dysplasia and the importance
The Abnormal growth of cells which may POTENTIALLY be cancerous. This is also called CIN or Cervical intraepithelial neoplasia.
CIN is NOT Cancer. It is usually remediable.
Squamous: Type of Cell in the lining of the cervix(Type of Epithelium)
Epithelium: Thin Tissue lining the hollow structures of the body including the GI tract.
Intraepithelial: Within the epithelium
LSIL = Low-grade squamous intraepithelial lesion and CIN 1 is included in this. LSIL is observed on PAP Smear while CIN is on biopsy.
HSIL = High-grade squamous intraepithelial lesion (HSIL), encompasses CIN 2 or CIN 3.
Image: Bethesda classification of Cervical Lesions:
CIN 1 is referred to as low-grade squamous intraepithelial lesion (LSIL).
CIN 2 that are p16-negative are LSIL, and those that are p16-positive are high-grade squamous intraepithelial lesions (HSIL).
Not all CIN will go on to develop Cancer. Some remain constant. The Immune system eliminates some.
A Small Percent, if untreated will develop Cancer.
HPV Testing and the PAP Smear:
Since Cervical Cancer develops over a period of time, the prudent way to prevent it is screening.
This consists of a PAP Smear + HPV test.
1. The PAP test involved taking cells from the cervix with a brush and examining them under a microscope after staining.
This allows us to detect the CIN stages EARLY. An abnormal PAP result requires further testing. This is known as COLPOSCOPY. A gynaecologist will use a colposcope to examine the cervix closely. If an abnormal area is suspected a biopsy is done. This involves removing a small piece of the suspicious area. This is later observed under a microscope by trained pathologists.
2.HPV Testing: Along with a PAP smear, an HPV test is recommended. It is tested with the sample taken for a PAP Smear. Since most cervical cancers are related to PRIOR HPV infection, an HPV test is a must. HPV 16 and 18 are most commonly responsible for Cervical abnormalities.
Next Steps after the tests:
1. If either is abnormal – Colposcopy is carried out
2. If both are normal i.e negative – No PAP test for 5 years..
3. If CIN 1 or LSIL detected: Follow up for 2 years. No immediate treatment is given.
4.If CIN 2 or HSIL detected: In a younger woman, follow up is recommended but varies case to case.
5. for CIN 3, HSIL and higher – Treatment is carried out in multiple ways to remove the cancerous cells. The options are LEEP(loop electrical excision procedure ), cryocautery, electrocautery etc.
What age should screening be started?
Age 21 is the ideal age regardless of sexual intercourse.
Outcomes of CIN
70% of CIN-1 will regress in 1 year. 90% within 2 years.
50% of CIN-2 will regress in 2 years.
11% of CIN-1 & 22% of CIN-2 will go on to Cancer which is confined and not invading surrounding structures(Carcinoma in Situ).
Progression to cancer usually takes around 10-15 years. It is possible for cancer to NOT progress through the earlier grades of CIN and directly present as a high-grade cervical cancer.
Symptoms and Signs
Women with CIN have no symptoms or Signs. All visible lesions need to be biopsied.
Vaccines against HPV-16 and HPV-18 may prevent more than 70% of cervical cancers.
If a woman tests negative for HPV, the vaccine can prevent 100% of Cervical cancers linked to HPV 6,11,16 & 18.
The protection lasts for around 5 years. The recommended age for vaccination is 11 to 12 years.
Who should be vaccinated?
Females ages 13 through 26 years
Males ages 13 through 21 years who have not been vaccinated.
What are the side effects of the vaccine?
They are considered quite safe. The usual side effects are pain, itching, irritation, redness and low-grade fever.
What is the dose of the vaccine?
Children between 11-12 years: 2 doses of the vaccine, 6 months apart
Above 15 years: 3 doses 6 months apart
To summarize, Cervical cancer is extremely common in Indian Women.
To know more about our PAP Smear and HPV Test Combination click here.
To read more from the CDC about the HPV test click here.
Cervical cancer is a sexually transmitted disease when linked to HPV
HPV 16 & 18 are commonly responsible.
Cervical cancer progresses over many years and is PREVENTABLE.
Screening using PAP Smears and HPV testing is a must.
HPV Vaccines are quite effective in prevention.