Flashcards in cervical caner lab Deck (15)
What are the risk factors for HPV infection?
- Risky sexual behaviour, many sexual partners, being younger than 25, starting to have sex at a young age (
Role of HPV in cervical cancer
- Persistent infections increase the risk
- HPV divided into low (6 and 11) and high (16 and 18) oncogenic risk categories
- The duration of the infection is related to HPV type
o The longer the infection, the higher oncogenic risk it will be
How does it cause cervical cancer?
Integration of HPV into host cell DNA allows for an overexpression of E6 and E7 viral genes which encode proteins
- Both E6 and E7 enhance degradation of p53, therefore interrupting cell death pathways
- E7 binds to p21 and prevents its function as a cell cycle inhibitor
- E7 inactivates the retinoblastoma gene (Rb) blocking its proliferation-inhibitory function
Screening programs and vaccination to prevent cervical cancer
- National cervical cancer screening program: to reduce morbidity and deaths from cervical cancer, in a cost-effective manner through an organised approach to cervical screening
o Encourages women in the target population to have regular pap smear
What is the pap smear test?
- ells from the transformation zone of the cervix are obtained via a spatula or brush
- Smeared onto slide, fixed and stained using Papanicolaou method
- Available in Australia in 2006
- Designed to reduce incidence of cervical cancer caused by HPV types 16 and 18 and condylomas caused by HPV 6 and 11.
- Gardasil—quadrivalent vaccine currently used for the Australian national HPV vaccination program
Clinical features of cervical cancer
- Mostly asymptomatic, abnormal pap smear, abnormal bleeding (post-coital or intermenstrual), pain, haematuria and weight loss
- Early lesions visible only on colposcopy
- Focal induration, ulceration, elevated granular areas that bleeds when touched
- Advanced lesions
o Endophytic – ulcertated
o Exophytic – polypoid or papillary tumour mass
- Squamous cell carcinoma 80% of all cases
o Precursor CIN 3, characterised by nests and infiltrative tongues of malignant squamous cells with large, irregular and hyperchromatic nuclei invading beyond the epithelium into the cervical stroma
treatment of cervical cancer
- Depends on the clinical stage (see below)
- Early invasive carcinoma cone biopsy only
- Invasive lesions hysterectomy and lymph node dissection
Advanced lesions surgery and/or adjunct radiotherapy and chemotherapy
What is the significance of an aceto-white area in cervical cancer testing?
It is a hall mark of colposcopic diagnosis of CIN
What is an LLETZ?
Large loop excision of the transformation zone
What are histological changes of SCC?
Nests of tumour cells, keratinous pearls and reduced stroma, with lymphocytes.
There can also be a poor differentiation with a high degree of pleomorphism and mitotic activity
Keratinizing squamous cell carcinomas have polygonal cells with bizarre shapes
What type of cell lines the ectocervical mucosa?
Stratified squamous epithelium
What type of cell lines the endocervical mucosa?
Simple columnar epithelium. This is mucous secreting