Pocket ObGyn – Human Papilloma Virus (HPV)
See Abbreviations
Epidemiology
- Most common sexually transmitted virus worldwide
- Most common viral cause of cancer worldwide (5% of all cancers)
- Worldwide prevalence around 10% although 80% of sexually active adults will acquire an HPV infxn in their lifetime (Am J Epidemiology 2000;151:1158)
- Prevalence highest in teenagers & young women shortly after sexual debut (JAMA 2007;297:813)
- Risk factors: Young age, early age at 1st intercourse, number of sexual partners, other STIs (HIV, HSV, chlamydia), smoking, low education, minority race
Microbiology
- DsDNA virus. ~40 strains of HPV infect the anogenital tract & can be a/w anogenital warts & cancer including cervical, vaginal, vulvar, oropharyngeal, anorectal, & High-risk HPV types cause cancer: HPV16, 18, 31, 33,
35, 39, 45, 51, 52, 56, 58, 59, 66, 68. Types 16 & 18 account for 70% of cancer cases (N Engl J Med 2003;348:518). Low-risk HPV types cause warts: HPV6, 11, 42, 43, 44.
- Transmission usually through intercourse, but can occur through close personal
- Warts esp contagious ® infectivity up to 60%.Vertical transmission may be as high as 55% during vaginal Infxn generally transient ® 90% cleared by 24 mo (Vaccine 2006;24:S42).
- Risk factors for persistence/progression of HPV to precancerous lesions: Older age, immunosuppression, cigarette smoking, high-risk genotypes (Vaccine 2006;24:42).
- HPV’s carcinogenic potential related to (J Virol 1989;63:4417)
E6 gene a/w inactivation of p53 (tumor suppressor prot)
E7 gene a/w inactivation of the Rb apoptotic pathway
Clinical Manifestations
- Based on strain & site of Include genital & nongenital warts (condyloma acuminatum), Bowen’s dz (squamous carcinoma in situ), giant condyloma, & intraepithelial neoplasia.
- Cervical dysplasia: HPV infxn leading to cellular atypia & progression from low-grade to high-grade histology is the basis for cervical cancer (J Pathol 1999;189:12) See also Chaps 1 (screening) and 21 (cancer).
- Genital warts (condylomata acuminata): Caused by low-risk HPV 6 & 11 (90%) (MMWR Recomm Rep 2010;59:1). Usually asx papillomatous growths, commonly appear around Vary in appearance: Hyperpigmented, papilliform, flat, papular, pedunculated (in contrast to condylomata lata of syphilis which is flat & velvety). Regression occurs ~20–50% of cases. Persistence a/w immunocomp status & dev of squamous cell carcinoma. Lesions a/w HPV 6 & 11 are almost 100% benign. 30% of flat condylomas a/w high-risk types & have oncogenic potential.
Diagnostic Studies
- HPV testing: Current testing exists in either a binary (± high-risk HPV) form or specific genotyping that can detect presence of specific strains (HPV16, HPV18). See Ch. 1 and
- Genital warts: Dx of condyloma made by 5% acetic acid solution ® causes acetowhite change for easier identification. Bx considered if dx uncertain, lesion does not respond to rx or worsens w/ therapy, pt immunocomp, warts are pigmented, indurated, fixed, bleeding, or ulcerated.
Treatment (MMWR Recomm Rep 2010;59:1)
- Rx goal for genital warts is amelioration of sx & cosmetic improv
- CDC recommended regimens: Patient-applied:
Podofilox 0.5% gel applied BID ´ 3 d followed by 4 d off, up to 4 cycles Imiquimod 5% cream applied qhs 3 ´ a week for up to 16 w Sinecatechins 15% ointment TID for up to 16 w
5-fluorouracil 5% cream applied BID ´ 5 d followed by 9 d off, up to 4 cycles (Safety of all of these therapies in Preg is unk & should not be used)
Provider-administered: Cryotherapy, trichloroacetic acid 85%, surgical removal (excision, laser, electrosurgery, infrared coagulation)
- Ppx (CDC-ACIP 2011)
Bivalent (Cervarix) & quadrivalent (Gardasil) vaccine. Quadrivalent includes HPV 16, 18 as well “low-risk” strains HPV 6, 11.Vaccination recommended in females & males 11–26 yo. Bivalent effective against HPV 16, 18.