Cervical Cancer Screening

INTRODUCTION

• Carcinoma of the cervix is the most common cause of cancer death in women worldwide.

• On average, cervical cancer takes at least a decade to develop from a focus of a cervical squamous intraepithelial lesion.

• Human papillomavirus (HPV) is the primary cause.

• SCC of the cervix occurs almost exclusively in women who have been sexually active due to exposure to HPV.

• The incidence of cervical cancer has decreased significantly through HPV vaccination, cervical cancer screening, colposcopy and colposcopically directed cervical biopsy.

• The cervical screening test uses a primary HPV test with partial genotyping. If an oncogenic HPV type is detected, a ‘reflex’ liquid-based cytology (LBC) is performed on the cervical sample to guide further management.

Clinical presentation Many patients with cervical cancer are asymptomatic and when early symptoms do arise they are often dismissed as of little consequence.

Symptoms, if present, may be:

• vaginal bleeding, esp. postcoital bleeding, intermenstrual

• vaginal discharge

• symptoms of advanced disease (e.g. vaginal urine or flatus, weakness)

Screening recommendations

• Begin cervical screening at 25 years (or two years after first sexual intercourse, whichever is later)

• An exit test can be performed at age 70–74 years

• Both HPV-vaccinated and non-vaccinated women require screening

• Screening applies only to asymptomatic women. Women with postcoital or persistent intermenstrual bleeding require a co-test (both HPV test and diagnostic LBC), and referral for an appropriate investigation to exclude malignancy.

PERFORMING A CERVICAL SCREENING TEST

The importance of a good specimen

The optimal cervical sample contains:

• sufficient mature and metaplastic squamous cells to indicate adequate sampling from the whole of the transformation zone

• sufficient endocervical cells to indicate that the upper limit of the transformation zone was sampled; and to provide a sample for screening of adenocarcinoma and its precursors

Results:

• HPV not detected:

  • – repeat in 5 years

• HPV not 16/18 detected:

  • – negative cytology, possible low-grade intraepithelial lesion (pLSIL) and definite LSIL, repeat HPV test in 12 months

  • – high-grade epithelial lesion (HSIL), refer for colposcopy

• HPV 16/18 detected:

  • – all cytology results, refer for colposcopy