Pocket ObGyn – Cervical Cancer Screening
See Abbreviations
Epidemiology & Definitions (Obstet Gynecol 2012;120:1222)
- 2nd most common cancer in women Mean age at dx: 40–59 y; bimodal distribution peaks 35–39 y & 60–64 y. Cervical cancer ¯ 50% from 1975 to 6.6/100000 women in 2008 due to pap smear screen.
Pathophysiology
- Caused by HPV An effective immune system clears HPV infxn; cervical cancer thought to be from long-term HPV infxn. >90% young healthy women clear cervical HPV w/i 1–3 y.
- HPV: E (early) & L (late) E6, E7 proteins expressed in malignant E6 ® degradation of tumor suppressor p53 ® cell proliferation. E7 binds tumor suppressor pRb (retinoblastoma gene product) ® release E2F transcription factors ® replication & cell division. Unchecked cell cycle ® malig.
High-risk HPV strains: 16, 18, 31, 33, 35, 45, 58 are carcinogenic
Low-risk HPV strains: 39, 51, 52, 56, 59, 68, 73, 82 (6, 11 cause genital warts)
- High-risk pts: Increased sexual contacts, new sexual partner, HIV+ or immunosuppression. These pts do not effectively clear the
Pap Smear Guidelines (J Low Genit Tract Dis 2012;16:175)
- Pap smear adequate if transformation zone (junction of squamous & columnar cells w/ embryonic component) is present for cytologic Sens 51%; spec 98%. HPV typing from pap smear cells can also be performed.
Start screening ³21 yo regardless of sexual Hx. Do NOT screen £21 yo, except HIV+ pts. Recent ¯ in testing frequency retains benefits but minimizes harms & unnecessary procedures. Regardless of pap screening, annual Gyn exam recommended for all. If abn pap, consult current ASSCP guidelines (www. asccp.org).
| Pap smear screening schedules | |||
| USPSTF | ASCCP | ACOG | |
| When to start screening | 21 yo | 21 yo | 21 yo |
| How frequently should you test? | |||
| Age 21–29 yo (pap smear alone if nml) | Every 3 y | Every 3 y | Every 3 y |
| Age 30 & older | |||
| Pap smear alone if nml | Every 3 y | Every 3 y | Every 3 y |
| Pap smear w/ HPV cotesting | Every 5 y | Recommended, but no more frequently than every 5 y | Every 5 y as recommended strategy |
| Age to stop | 65 yo if
adequate screening |
65 yo w/ adequate screening & no h/o CIN 2+ in last 20 y | 65 yo if adequate screening & no h/o CIN 2, CIN
3, or adenoCa in situ or cervical cancer in last 20 y |
| After hysterectomy including cervical removal w/ no h/o CIN 2–3, adenoCa in situ, or prior cervical cancer in last 20 y | No pap screening needed, but annual exam for vaginal & vulvar dz should continue | ||
| HPV vaccinated | No change in screening | ||
| HIV+ women, immunocomp, or in utero DES exposure | Pap twice in 1st year after dx & then annually thereafter; referral to colposcopy w/ ASCUS or high-level dysplasia
(Obstet Gynecol 2010;116:1492) |
||
- Pap results reported as:
ASCUS: Atypical cells of undetermined significance
LSIL: Low-grade squamous intraepithelial lesion ~ corresponds to CIN 1
HSIL: High-grade squamous intraepithelial lesion ~ corresponds to CIN 2–3
AGC: Atypical glandular cells (means columnar cells, has association with CIN 2–3)
• Management:
ASCUS ® reflex high-risk HPV testing; if HPV positive refer to colposcopy; if HPV negative rpt according to age appropriate guidelines (www.asccp.org) – OR ® rpt pap in 6 mo ® if rpt = ASCUS or more refer to colposcopy, if negative return to annual screening
Pts w/ negative cytology & positive HPV cotesting should either be referred directly to colposcopy or perform high-risk HPV typing. If high-risk type then referral to colposcopy should be made. If no high-risk type (16 or 18) then rpt w/ coscreening in 1 y.
LSIL/HSIL/AGC: Refer to colposcopy
| Special cases: Screening in pregnancy and age <21 y | |
| Cervical cancer screening in pregnancy (ASCCP) | |
| ASCUS regardless of HPV | Refer to colposcopy at 6 w postpartum |
| LSIL | Refer to colposcopy during Preg or at 6 w postpartum, no ECC during Preg |
| HSIL/AIS/AGS | Refer to colposcopy during Preg, no ECC during Preg |
| Adols should not be screened before 21 yo, but if they have been: | |
| Past ASCUS, LSIL, CIN 1 | Rpt annually for 2 y & then further screening delayed until 21 yo; refer to colposcopy if persists |
| Past HSIL, AGC, ASC cannot exclude HSIL, CIN 2–3 | Refer to colposcopy w/ ECC |
| Adols w/ HIV | Pap twice in 1st y after dx & then annually thereafter; referral to colposcopy for ASCUS or higher (Obstet Gynecol 2010;116:1492) |
Colposcopy
- Definition: Direct visualization of the cervix, vagina, & vulva w/ a mobile lighted binocular microscope to identify, map, & bx cervical Deemed adequate if
transformation zone is visualized on all sides since this is the region in which abn changes occur.Visualization is aided by:
Acetic acid: Dehydrates cells ® lighter appearance in dysplastic cells w/ n/c ratio/ chromatin = “acetowhite changes.”
Lugol iodine: Stains nml cervicovaginal epithelial cells dark due to high glycogen content, while dysplastic cells are lighter; used in place of or in addition to acetic acid.
- Abn colposcopic findings include:
Punctation: Small bld vessels visible as small dots
Mosaicism: An interspersing of white & nml epithelial cells
Acetowhite changes: A range of white-hued epithelium w/ diffuse or sharp borders
Atypical vessels: Larger vessels w/i lesions may indicate a more advanced lesion
- Any abn lesions are biopsied to evaluate for preinvasive cancer; colposcopy does not always mean bx; only abn lesions & endocervical canal are
- Endocervical curettage: Curetting the endocervical canal to obtain glandular cells or nonvisualized
- Bx results: Reported as:
CIN 1/mild dysplasia: Confined to lower 1/3 of squamous epithelium
CIN 2/mod dysplasia: Abn cells extending into the middle third of epithelial layer CIN 3/sev dysplasia: Abn cells extending into the upper third of epithelium CIS: Full thickness abn cells w/ no invasion of basement membrane
Cervical Dysplasia Management (Obstet Gynecol 2013;121:829)
- CIN 1 ® can follow conservatively w/ surveillance; consider conization if persists >2 y
- CIN 2 ® consider conization or follow w/ rpt pap/colposcopy, esp if young
- CIN 3 ® conization/LEEP
- CIS ® conization
- Invasive cancer ® refer to Gyn oncology (see 21)
- See ASCCP for most up to date recommendations (www.asccp.org)