Overview
Cervical screening is one of the cornerstones of a gynaecological visit.
Cervical intraepithelial neoplasia (CIN) is commonly diagnosed between 20 and 30 years.
Carcinoma in Situ is commonly diagnosed between 35 and 45 years.
It takes approximately 10 years for cervical dysplasia to progress to carcinoma.
- Indications for cervical cancer screening
- Any woman who has ever had sexual intercourse
- Women aged 25-49 years
- Women aged 50-65 years are still at risk and can receive screening every 5 years
- Screening methods for cervical cancer
- Pap smear is the primary screening method in these situations:
- Women 21 – 29 years old
- HPV testing unavailable
- Women not eligible for VIA/VILI because the squamocolumnar junciton is not visible
- HIV-positive women as co-testing with HPV DNA
- HPV DNA testing is the primary screening method for women 30 – 65 years old
- VIA/VILI is the primary screening method where:
- HPV testing is unavailable or loss-to-follow-up is a risk
- HIV positive or immunosuppressed every 1 year along with pap smear or every 2 years along with HPV DNA
- Pap smear is the primary screening method in these situations:
Human Papillomavirus (HPV) DNA Testing
Some guidelines use a HPV first system, where pap smears are only performed when high-risk HPV strains are positive
HPV testing results and intervention
| High-risk HPV | Intervention |
|---|---|
| Negative | Return to normal screening |
| Positive | Perform pap smear |
The Pap Smear
Cellular debris can give clues to cancerous processes.
Grading of abnormal cytology from pap smears
| Grading acronym | Description |
|---|---|
| ASC-US | Atypical squamous cells of undetermined significance |
| LSIL | Low-grade squamous intraepithelial lesion |
| ASC-H | Atypical squamous cells, cannot exclude high-grade SIL |
| HSIL | High-grade squamous intraepithelial lesion |
| AGC | Atypical glandular cells |
- Scheduling
- First Pap smear at 21 years
- Subsequent Pap smears every 3 years until 30 years
- Past 30 years routine Pap smears are done every 3 years
- If HPV DNA testing is added regular pap smears may be done every 5 years
- When to discontinue Pap smears (ACOG)
- From age 65 pap smears may be discontinued if:
- The patient has never had CIN 2+
- The patient is more than 20 years removed from the treatment of CIN2+
- Total hysterectomy is performed for reasons other than cancer, provided there was no abnormal pap smear in the past 20 years
- From age 65 pap smears may be discontinued if:
Cytology report and intervention
| Cytology | Intervention |
|---|---|
| Abnormal cytology | Colposcopy |
| Normal cytology but high-risk HPV positive | Repeat screening at 12 months. |
| Normal cytology but high-risk HPV negative at 12 months | Return to normal screening |
| Normal cytology but high-risk HPV positive at 12 months | Repeat testing at 12 months |
| Normal cytology but high-risk HPV positive at 24 months | Colposcopy |
| Normal cytology but high-risk HPV negative at 24 months | Return to normal screening |
| Inadequate sample | Repeat pap smear in 2 monrhs |
| Two consecutive inadequate samples | Colposcopy |
Colposcopy
Morphological changes (dysplasia) in the cervix and vagina can be visualised by staining with acetic acid or Lugol’s iodine (VIA/VILI).
- Morphological changes
- Acetowhite areas – areas that stain white with acetic acid
- Cobblestoning – areas that are “mosaic”-like in appearance
- Areas that display punctated vessels
- Areas with abnormal vessel geography )
- Contraindications to visual inspection with acetic acid
- Women who are very ill
- Women in the 2nd and 3rd trimester of pregnancy
- Women < 6 weeks after delivery
- Women with cauliflower-like growth or ulcer (fungating mass)
- Women with previous history of treatment of cancerous lesions
- Women with known allergy to acetic acid
- Women with a history of total hysterectomy
Histopathology
Histopathologists assess the biopsy and report it based on the depth of abnormal cellular invasion and whether or not the basement membrane is intact
CIN grading of cervical dysplasia
| Grade | Description |
|---|---|
| CIN 1 | Dysplasia restricted to the deep 1/3 of the epithelium. This rarely progresses to cervical cancer. |
| CIN 2 | Dysplasia occupies approximately 2/3 of the epithelium |
| CIN 3 | Dysplasia occupies more than 2/3 of the epithelium |
| CIS | Full thickness dysplasia |
| Invasive cervical cancer | Dysplastic cells penetrate the basement membrane |
Natural History of CIN Lesions
| Spontaneous regression | Persists | Progress to CIN-III | Progress to invasive cancer | |
|---|---|---|---|---|
| CIN 1 | 60% | 30% | 10% | < 1% |
| CIN 2 | 40% | 35% | 20% | 5% |
| CIN 3 | 30% | 50% | N/A | 12-22% |
- Treatment of cervical intraepithelial neoplasia (CIN)
- Surgical excision (cervical conization)
- Loop electrical excision procedure (LEEP)
- Large loop excision of the transformation zone (LLETZ)
- Cryosurgery
- Cold knife conization (CKC) using a scalpel
- Surgical excision (cervical conization)