prevention of cervical cancer Flashcards
List low risk and high risk HPV types
low risk: 6, 11. High risk: 16, 18, 31, 35, 45, 58, 56
What percentage of people with HPV develop invasive carcinoma
1.30%
guidelines for cervical cytology and cancer screening
Cervical cancer screening should begin at age 21 years. Screening before age 21 is not indicated. Cervical cytology screening every 3 years btw 21-29 yrs, and every 5 years btw 30-65 years. Stop at 65 if has not had CIN 2/3 for previous 20 years
Where do premalignancy squamous lesions of cervix arise
The squamo-columnar junction: the interface between the stratified squamous epithelium of the ectocervix and the glandular epithelium of the endocervix
- Name the two major epithelial cell types of the cervix and identify them on a cervical cytology specimen interpreted as normal.
stratified squamous epithelium of the ectocervix and the glandular epithelium of the endocervix. The endocervix surrounds the os and the ectocervix surrounds the endocervix
Normal pap test results
Superficial squamous cells: abundant cytoplasm, dark pyknotic nucleus. Endo-cervical cells: may appear in a “honeycomb” array, with distinct cell membranes due to cytoplasmic mucin.
List the low grade squamous intraepithelial lesions (LSIL) and high grade squamous intraepithelial lesions (HSIL)
LSIL: condyloma, mild dysplasia, CIN1. HSIL: moderate dysplasia, severe dysplasia, carcinoma in situ, CIN II/III
- Name the types of human papilloma virus associated with cervical warts, cervical dysplasia, and cervical carcinoma.
cervical warts: 6 and 11. cervical dysplasia/ carcinoma: 16 and 18
How many layers in the cervix epithelium. Cytology vs histology
8-12 layers. Histology takes all 12 layers, cytology only takes top cells
- Diagram the changes in the squamous epithelial layer accompanying progressive levels of cervical dysplasia and carcinoma.
CIN1: mild dysplasia, proliferation up to the lower third of epithelium. CIN2: moderate dysplasia: proliferation up to upper two thirds. CIN3: severe dysplasia, entire epithelium is abnormal. Invasion: cells extend beyond basement membrane
Describe cells of LSIL and HSIL
LSIL: Evidence of HPV infection include perinuclear cytoplasmic clearing (koilocytosis) due to viral proteins around nucleus. Also enlarged, hyper-chromatic nuclei with abnormal chromatin distribution, irregular nuclear contour and abundant cytoplasm. HSIL: Higher nuclear to cytoplasmic ratio.
HPV latency
Virus resides in epithelial cells in levels that ccant be detected by cervical swabs. They can reactivate months to years later
treatment of abnormal biopsy
can use cryotherapy, laser ablation and excision
- Identify the most common histologic types of invasive cervical carcinoma and recognize the cytologic and histologic features of these lesions and their associated premalignant lesions (CIN 1-3 and AIS).
HPV is associated with Most cases of invasive squamous cell carcinoma and LSIL/ HSIL. A majority of endocervical adenocarcinoma are also associated with HPV infections.
- Explain the basis of HPV vaccines, including antigenic component, viral types covered, efficacy, and clinical utility.
- Gardasil is a quadrivalent HPV 6/11/16/18 L1- virus like particle vaccine. Prophylactic efficacy of 98.8% in reduction of genital warts, CIN2/3 and adenocarcinoma in situ if never exposed, and 44% reduction if previous infection with one of the types. 2. Cervarix is bivalent HPV 16 and 18. Protection against CIN2/3 and adenocarcinoma is 93%. More effective at preventing dz attributable to other viral types like HPV 31 and 45
