Human Papillomavirus (HPV)
1. Introduction
- Definition: Human papillomavirus (HPV) is a group of over 200 related viruses, some of which cause benign warts while others are associated with cancers, including cervical, anal, penile, and oropharyngeal cancers.
- Epidemiology: HPV is the most common sexually transmitted infection (STI) worldwide. Nearly 80% of sexually active individuals will be infected at some point.
- Significance: While many HPV infections clear spontaneously, persistent infections with high-risk strains (e.g., HPV-16 and HPV-18) can lead to cancer.
2. Causes and Risk Factors
- Causes:
- HPV is transmitted through direct skin-to-skin contact, primarily via vaginal, anal, or oral sex.
- Non-sexual transmission is possible through contaminated surfaces or vertical transmission (mother-to-child during childbirth).
- Risk Factors:
- Early sexual activity and multiple sexual partners.
- Unprotected sex and lack of HPV vaccination.
- Weakened immune system (e.g., HIV, immunosuppressive therapy).
- Smoking, which increases persistence of high-risk HPV strains.
3. Pathophysiology
- HPV infects epithelial cells, integrating into the host genome in high-risk cases.
- Low-risk HPV types (e.g., HPV-6, HPV-11) cause benign warts, while high-risk types (e.g., HPV-16, HPV-18) interfere with tumour suppressor genes (p53, Rb), leading to cancerous transformations.
4. Symptoms and Features
- Asymptomatic in most cases – the immune system clears the virus in 1–2 years.
- Genital Warts (HPV-6, HPV-11):
- Painless, flesh-coloured growths in the genital or anal area.
- May be single or clustered, resembling cauliflower.
- High-Risk HPV Infections (HPV-16, HPV-18):
- Often asymptomatic until precancerous or cancerous changes occur.
- Symptoms depend on cancer site:
- Cervical cancer: Abnormal vaginal bleeding, pelvic pain.
- Oropharyngeal cancer: Sore throat, difficulty swallowing.
- Anal cancer: Rectal bleeding, pain.
5. Complications
- Persistent HPV infections can lead to:
- Cervical, anal, vaginal, vulvar, penile, and oropharyngeal cancers.
- Respiratory papillomatosis in infants (if passed during childbirth).
- Emotional and psychological distress due to genital warts.
6. Diagnosis
- Genital Warts: Clinical examination.
- HPV DNA Testing:
- Used in cervical cancer screening (Pap smear + HPV test).
- Identifies high-risk HPV types.
- Pap Smear (Cytology): Detects precancerous changes in cervical cells.
- Biopsy: For abnormal lesions suspected of malignancy.
7. Management Overview
- Goals: Remove warts, monitor and treat precancerous lesions, and prevent HPV-related cancers.
- Approach:
- Genital warts: Topical treatments, cryotherapy, or surgical removal.
- Precancerous lesions: Close monitoring, excisional procedures (LEEP, conization).
- Cancer: Surgery, radiation, chemotherapy, or immunotherapy.
8. Treatment Options with Cost (USD)
- For Genital Warts:
- Imiquimod (Aldara) cream: ~$100–$300 per course.
- Podophyllotoxin (Condylox): ~$50–$150 per bottle.
- Cryotherapy: ~$100–$300 per session.
- For Precancerous Lesions:
- LEEP (Loop Electrosurgical Excision Procedure): ~$500–$1,500.
- Conization: ~$1,500–$3,000.
- For HPV-Related Cancer:
- Chemotherapy and radiation: ~$10,000–$50,000 per treatment course.
9. Advanced Treatment Options with Cost (USD)
- Laser Therapy for Warts: ~$500–$2,000 per session.
- HPV Vaccination (Prevention):
- Gardasil 9 vaccine (protects against 9 HPV types): ~$200–$250 per dose (3 doses required).
10. Pharmacological Treatment
- First-line for Genital Warts: Topical therapies (imiquimod, podophyllotoxin).
- For Persistent Warts: Cryotherapy, laser ablation, or surgical removal.
- For High-Risk HPV with Cervical Dysplasia: Excisional procedures (LEEP, conization).
11. Medication Tables
Table 1: Doses and Side Effects
| Drug | Indication | Dose | Common Side Effects |
|---|---|---|---|
| Imiquimod | Genital warts | Apply 3 times/week for up to 16 weeks | Redness, burning, irritation |
| Podophyllotoxin | Genital warts | Apply twice daily for 3 days, then stop for 4 days | Skin irritation, pain |
| Trichloroacetic Acid | Resistant warts | Applied by doctor weekly | Burning, ulceration |
| HPV Vaccine (Gardasil 9) | HPV Prevention | 3 doses over 6 months | Injection site pain, mild fever |
Table 2: Brand Names and Approximate Costs (USD)
| Drug | Brand Names | Approx. Cost |
|---|---|---|
| Imiquimod | Aldara, Zyclara | $100–$300 per course |
| Podophyllotoxin | Condylox | $50–$150 per bottle |
| Trichloroacetic Acid | N/A | $100–$200 per session |
| HPV Vaccine | Gardasil 9 | $200–$250 per dose |
12. Lifestyle Interventions
- Practice safe sex (use condoms and dental dams).
- Avoid smoking, which increases HPV persistence.
- Get regular Pap smears and HPV screenings.
- Encourage HPV vaccination before sexual activity starts.
13. Monitoring Parameters
- Regular Pap smears for cervical cancer screening.
- Follow-up visits after treatment for genital warts.
- Monitor high-risk HPV infections for potential progression to cancer.
14. Patient Counseling Points
- HPV is common, and most infections clear naturally.
- The HPV vaccine is highly effective in preventing high-risk strains.
- Genital warts are treatable but may recur.
- Regular cervical screening is crucial for early detection of precancerous changes.
- Partners of HPV-infected individuals should also consider screening.
15. Special Populations
- In Pregnant Women: Avoid podophyllotoxin; cryotherapy or trichloroacetic acid is preferred for warts.
- In Immunocompromised Patients: Higher risk of persistent HPV infection; aggressive monitoring and treatment are needed.
- In Adolescents: HPV vaccination is most effective when given before sexual activity.
16. Prevention
- HPV Vaccination (Gardasil 9, Cervarix): Recommended for both males and females (ages 9–45).
- Safe Sexual Practices: Condom use lowers but does not eliminate risk.
- Routine Screening: Pap smears and HPV testing for early detection.
17. FAQs
- Is HPV curable? → No, but most infections clear naturally.
- Can men get HPV? → Yes, and it can cause genital warts and cancers.
- Does HPV always cause cancer? → No, only persistent high-risk strains do.
- Can I get HPV from oral sex? → Yes, it can cause oropharyngeal cancers.
- Does the vaccine work if I already have HPV? → It prevents future infections but does not cure existing ones.
