12-phase flow (12)

1. 1FRAME
   Confirm cervical-screening scope: asymptomatic person WITH A CERVIX, age 21-65. Excludes <21 (Grade D — transient HPV/regressive CIN, overdiagnosis dominates), >65 with adequate prior negatives (Grade D), post-total-hysterectomy for benign indication with no CIN2+ history (Grade D — no pretest target), and any visible lesion/abnormal bleeding (→ diagnostic work-up, not screening) (USPSTF 2018 PMID 30140884)
   inputs: age, has_cervix
   advance: Asymptomatic, has cervix, age 21-65, not in a Grade-D stop category
2. 2ENTRY
   Trigger: routine wellness visit, overdue/never-screened recall (equity — self-collection option), prior-abnormal-result follow-up, post-treatment-CIN surveillance entry, or HPV-vaccinated-cohort review (USPSTF 2018; ACS 2020 PMID 32729638)
   advance: Entry trigger captured
3. 3CONTEXT
   Set the pre-test prevalence prior: age band, prior cytology/hrHPV/genotype results (CONDITIONAL prior — prior-negative-hrHPV greatly lowers current-abnormality risk, Egemen PMID 32243308), hysterectomy status + indication, HIV/immunocompromise, HPV-vaccination status (Lei NEJM 2020 IRR 0.37 PMID 32997908 — prior shifts, protocol unchanged), pregnancy, DES exposure. This phase SETS the Bayesian prior — modality choice flows from it
   inputs: age, prior_screening_results, hysterectomy_status, hpv_vaccination_status, pregnancy_status
   advance: Pre-test prevalence tier + age band assignable
4. 4RED_FLAGS
   A visible cervical lesion, abnormal/post-coital bleeding, or new symptoms = DIAGNOSTIC indication → exit average-risk screening to diagnostic colposcopy/work-up. HIV/immunocompromise → off-interval more-frequent screening (not average-risk). Rare hereditary look-alike (e.g., Peutz-Jeghers cervical adenoma malignum) → genetics referral (NCCN). Symptomatic cervicitis/PID is a gyn look-alike — route to gyn.pelvic-inflammatory-disease.core.v1, do NOT process as screening
   inputs: abnormal_vaginal_bleeding_or_visible_lesion, immunocompromised_or_hiv
   actions: workup.genetic_counseling
   advance: Diagnostic/look-alike indications excluded or routed; average-risk eligibility confirmed
5. 5INITIAL_WORKUP
   Order the age-band-appropriate screen — the test with its fixed characteristics: 21-29 cytology q3y (sens ~55.4% single-test, Mayrand PMID 17942871); 30-65 primary hrHPV q5y (sens ~94.6%, PREFERRED per ACS 2020 / USPSTF-2024-draft) OR co-test q5y OR cytology q3y (USPSTF 2018 Grade A PMID 30140884). Self-collected hrHPV (PCR-based, sens ratio 0.99 vs clinician — Arbyn PMID 30518635) offered to under-screened. Each order is the "treatment"
   inputs: age, self_collected_hrhpv
   actions: workup.cervical_screening_hpv_pap, panel.hpv_genotyping
   advance: Age-band-appropriate screen ordered (modality documented; self-collection offered to under-screened)
6. 6BRANCHING_WORKUP
   Genotype/cytology triage of the positive screen — the second conditional likelihood layer: HPV-16/18+ (high LR+) → immediate colposcopy; other-hrHPV+ → reflex cytology (NILM → 1-yr surveillance vs ASC-US+/abnormal → colposcopy per ASCCP risk %); co-test discordance resolved by the ASCCP risk table. Feeds the structured result into RISK_STRATIFICATION (ASCCP 2019 PMID 32243307; Egemen PMID 32243308)
   inputs: cytology_result, hrhpv_result, hpv_16_18_genotype
   actions: panel.hpv_genotyping
   advance: Every positive screen has a genotype/cytology-triaged ASCCP-risk-table input assembled
7. 7DIFFERENTIAL
   Average-risk vs special-population (HIV/immunocompromised, post-treatment-CIN, DES, pregnancy), AND true-positive (CIN3+/AIS/invasive) vs false-positive (transient HPV, reactive/inflammatory cytology, regressive CIN overdiagnosis). The false-positive cascade + over-screening overdiagnosis are encoded as harm DATA, not prose; screen-negative returns to interval (USPSTF 2018; ASCCP 2019)
   advance: Each result classified as average/special-pop and true/false-positive likelihood assigned
8. 8RISK_STRATIFICATION
   ASCCP 2019 risk-based management — the post-test decision engine: the current+recent-past result combination maps to an immediate & 5-year CIN3+ risk percentage → one of six actions: 5-y return to routine (5-y CIN3+ risk <0.15%), 3-y surveillance (~0.15-0.54%), 1-y surveillance (~0.55-3.9%), colposcopy/biopsy (immediate CIN3+ risk ≥4%), or expedited treatment (immediate ≥60%, e.g., HPV-16+ HSIL). Risk is CONDITIONAL on screening history (Perkins PMID 32243307; Egemen KPNC 1.5M PMID 32243308)
   inputs: prior_screening_results, immunocompromised_or_hiv, prior_cin_treatment, des_exposure
   actions: calc.asccp_risk_based_management
   advance: ASCCP risk % computed and the corresponding 1-of-6 action threshold assigned
9. 9TREATMENT
   The screen IS the intervention; document modality + shared decision (hrHPV-primary preferred 30-65 per ACS 2020 PMID 32729638). Adjacent primary prevention: HPV-vaccination catch-up through age 26 (ACIP) — does NOT change the screening interval (USPSTF 2018) but reduces future prevalence (Lei NEJM 2020 IRR 0.37 PMID 32997908). No pharmacotherapy in this engine
   actions: workup.hpv
   advance: Screen completed, modality + shared decision documented, HPV-vaccination status addressed
10. 10DISPOSITION
    All screening is ambulatory. ASCCP immediate CIN3+ risk ≥4% → colposcopy referral; CIN3+/AIS/invasive → gynecologic oncology (differential-as-data — no dedicated colposcopy/CIN terminal engine on disk). Symptomatic gyn look-alike → gyn.pelvic-inflammatory-disease.core.v1; HPV-vaccination need → prev.adult-immunization.core.v1; broader multi-cancer screening context → parent prev.cancer-screening.core.v1 (ASCCP 2019; USPSTF 2018)
    advance: Disposition + referral route documented per ASCCP risk tier
11. 11MONITORING
    Interval + recall by age band AND ASCCP risk tier: cytology q3y 21-29; hrHPV q5y or co-test q5y or cytology q3y 30-65 (hrHPV-primary preferred per ACS 2020 / USPSTF-2024-draft); negative-hrHPV safe ≥5y (10-y CIN3+ risk 0.31% ≈ 3-y post-cytology — Gilham ARTISTIC PMID 31219027); 1-yr/3-yr surveillance per ASCCP risk %; post-treatment-CIN HPV-based surveillance with a 25-yr elevated-risk tail; immunocompromised/HIV more frequent and beyond 65 (USPSTF 2018; ASCCP 2019)
    advance: Next-screen date set by age band + ASCCP risk tier; recall scheduled
12. 12FOLLOWUP
    STOP-screening / over-screening-harm logic (the deprescribing-equivalent): discontinue at >65 with adequate prior negatives (≥3 consecutive negative cytology OR ≥2 negative hrHPV/co-test in 10 y, most recent within 5 y) and no CIN2+ in 25 y; discontinue after total hysterectomy for benign indication with no CIN2+ history (USPSTF 2018 Grade D PMID 30140884). Patient education: over-screening harms (colposcopy/biopsy of regressive CIN, overtreatment), the value of NOT screening <21 / >65 / post-benign-hysterectomy, and that HPV vaccination does not change the interval (transitional — ACS 2020)
    inputs: age, hysterectomy_status
    advance: Stop-screening decision OR continued-interval education delivered and documented