Cervical cancers are caused by oncogenic, high risk types of HPV which are sexually transmitted. Most HPV infections go away on their own within 1-2 years without any sequels. Cervical infection with high risk HPV if persists can cause cellular changes which can develop into precancerous lesions and can eventually progress to cancer. It usually takes 10-20 years for a persistent infection with high risk HPV to develop to cancer.
Screening for cervical cancer-
It is done to detect precancerous and early cervical cancer lesions as these are completely curable. Two types of screening are available cytology based called as PAP smear and HPV testing. PAP can detect abnormal cells, infections and inflammation. HPV testing detects the presence of high risk HPV types in cervical cells.
Procedure- Done in a clinic during pelvic examination. A speculum is inserted in the vagina so that cervix is visible. Cells are taken with a wooden or plastic brush and sent to laboratory after fixing. Conventional one is on a glass slide and liquid is collected in a vial of liquid. In liquid, both cytology and HPV DNA can be done.
First test at age 21 if sexually active
Age 21-29 should be screened with PAP every 3 years
Ages 30-65 can be screened with PAP and HPV co-testing every 5 years or with PAP alone every 3 years
Women with high risk factors need to be screened more frequently and even after age 65. High risk are women with HIV, immunosuppresed, exposed to diethylstilbestrol before birth or treated for precancerous cervical lesion or cancer cervix
Women who had hysterectomy or removal of uterus and cervix need not be screened. If hysterectomy done for precancerous lesions then screening needs to continue
Normal- Report is negative for intraepithelial lesions or malignancy
ASCUS- Atypical squamous cells of undetermined significance. Cells are not totally normal but the doctor is uncertain. Maybe due to HPV or other factors
ASC-H –Atypical cells could be high grade and could be precancerous
LSIL- Low grade squamous intraepithelial lesion. It is a mild abnormality by HPV infection. Colposcopy with biopsy is usually done and may reveal mild dysplasia or CIN-1
HSIL – High grade squamous intraepithelial lesions. More severe and likely to convert to cancer if not treated. Also called as severe dysplasia or CIN-2 or 3
Squamous cell cancer is frank cancer of cervix
Abnormal PAP like LSIL needs colposcopy and biopsy and repeat screening after 1 year. If biopsy reveals CIN-2 or more, treatment should be done.
LEEP- Loop electrosurgical excision procedure
Cryotherapy- Abnormality is destroyed by freezing
Screening for women with CIN-2 or above should continue for 20 years even if they are above 65. Women vaccinated against HPV also need to be screened for cancer cervix.