Key Facts

Cervical screening is one of the most effective cancer prevention programmes. The shift to primary HPV testing has improved sensitivity for detecting high-grade cervical intraepithelial neoplasia. Primary care plays a central role in encouraging uptake and managing results.

Epidemiology

• Cervical cancer: approximately 3,200 new cases/year in UK; 850 deaths/year
• Screening coverage: approximately 70% of eligible women (target 80%)
• HPV prevalence in screening-age women: approximately 12-16%
• CIN2+: found in approximately 1.5% of screened women
• Cervical cancer is almost entirely preventable with vaccination and screening

Programme Structure

• Age 25-49: every 3 years
• Age 50-64: every 5 years
• Age 65+: only screened if recent abnormality or never/inadequately screened
• Primary HPV test on liquid-based cytology sample
• HPV positive samples reflexed to cytology; HPV negative = return to routine recall

HPV Biology

• Human papillomavirus (HPV) is the necessary cause of virtually all cervical cancers

• 200 HPV types; high-risk (oncogenic): HPV 16, 18, 31, 33, 45, 52, 58

• HPV 16 and 18 responsible for 70% of cervical cancers
• HPV infection is very common: 80% of sexually active people infected at some point; most clear within 1-2 years
• Persistent high-risk HPV infection leads to CIN → potential progression to invasive cancer over 10-20 years

Screening Context (Asymptomatic)

• Cervical screening is a screening programme for asymptomatic women
• Abnormal results prompt further investigation

Symptomatic Presentation (Refer — Do NOT Await Screening)

• Postcoital bleeding
• Intermenstrual bleeding
• Postmenopausal bleeding
• Abnormal vaginal discharge (blood-stained, offensive)
• Suspicious cervix on speculum examination
• These require investigation regardless of screening history

Red Flags

• Postcoital bleeding — refer for colposcopy regardless of screening status
• Visible cervical abnormality on speculum — 2-week-wait referral
• Persistent/unexplained vaginal bleeding — investigate

Bedside

• Cervical screening (liquid-based cytology) performed by trained sample-taker
• Speculum examination: assess cervical appearance

Laboratory

• Primary HPV test: PCR-based detection of high-risk HPV types
• Cytology (if HPV positive): liquid-based cytology classified as:
  • Negative
  • Borderline changes
  • Low-grade dyskaryosis (mild)
  • High-grade dyskaryosis (moderate/severe)
  • Invasive squamous/glandular neoplasia

Colposcopy

• Detailed examination of cervix with magnification after application of acetic acid (acetowhite changes) and Lugol's iodine (Schiller test)
• Punch biopsy for histological grading: CIN 1, CIN 2, CIN 3, CGIN

Special Tests

• HPV genotyping: some programmes genotype for HPV 16/18 specifically
• Cone biopsy or LLETZ: both diagnostic and therapeutic

Prevention

• HPV vaccination: Gardasil 9 (nonavalent) offered to all 12-13 year olds (1-2 doses depending on age at first dose)
• Reduces cervical cancer risk by >85% in vaccinated cohorts
• Catch-up vaccination available for those missed in school programme
• Screening remains important even in vaccinated women (vaccine does not cover all oncogenic HPV types)

Management of Screening Results

HPV negative:

• Return to routine recall (3 or 5 years)
• Reassure: >99.7% NPV for CIN2+

HPV positive, cytology normal:

• Repeat at 12 months; if still HPV positive, repeat at 24 months
• If HPV positive at 24 months (3rd test): refer to colposcopy
• If HPV negative at any point: return to routine recall

HPV positive, abnormal cytology:

• Refer to colposcopy

Treatment of CIN

• CIN 1: usually observed (60% regress spontaneously); repeat cytology/HPV at 12 months
• CIN 2/3: treatment recommended
  • LLETZ (large loop excision of transformation zone): most common treatment; performed under local anaesthetic
  • Cold knife cone biopsy: if LLETZ not suitable
  • Test of cure at 6 months: HPV test ± cytology

Follow-up

• After treatment for CIN2+: test of cure (HPV ± cytology) at 6 months
• If HPV negative at test of cure: return to 3-yearly screening for 10 years, then routine recall
• If HPV positive: colposcopy

Referral Criteria

• All abnormal cytology with HPV positive: colposcopy referral
• Persistent HPV positive (×3): colposcopy referral
• Symptomatic women (postcoital bleeding, suspicious cervix): urgent/2-week-wait referral regardless of screening history

• CIN 1: 60% regress spontaneously; 10% progress to CIN 3 over 10 years
• CIN 2: 40% regress; 20% progress to CIN 3
• CIN 3: >30% may progress to invasive cancer over 20 years if untreated
• After LLETZ for CIN2/3: recurrence rate 5-10%; test of cure identifies residual disease
• Cervical cancer (if diagnosed early — stage I): 5-year survival >95%
• HPV vaccination impact: projected to eliminate cervical cancer as a public health problem (incidence <4 per 100,000) in vaccinated cohorts by 2040s
• Screening effectiveness: prevents an estimated 5,000 deaths/year in the UK

NHS Cervical Screening Programme Summary

CIN Classification