Cancer Vaccines: Prevention and Treatment Roles
Cancer vaccines serve two distinct roles: proven prevention of virus-associated cancers (HPV and hepatitis B vaccines) and emerging therapeutic approaches for treating established cancers, though only preventive vaccines against oncogenic viruses have achieved widespread clinical success to date. 1, 2
Preventive Cancer Vaccines (Proven Efficacy)
Hepatitis B Vaccine
- The hepatitis B vaccine is recognized as the first anti-cancer vaccine because it prevents primary liver cancer (hepatocellular carcinoma). 1
- Universal childhood immunization against hepatitis B has decreased the incidence of hepatocellular carcinoma in children by 70-90% in endemic areas. 1
- Adult vaccination has been shown to decrease both the incidence and risk of developing hepatocellular carcinoma. 1
- Antibody titers ≥10 mIU/mL confer protection, with protective efficacy rates of 95% against chronic carrier states. 1
HPV Vaccine
- HPV vaccination prevents cervical cancer and other HPV-associated malignancies. 2
- Should be offered to all cancer patients up to age 26, and may be considered up to age 45, administered as a 3-dose series. 3
- This represents exceptional success in virus-associated cancer prevention. 2
Therapeutic Cancer Vaccines (Investigational)
Current Status
- Therapeutic cancer vaccines aim to boost anti-tumor immunity and promote tumor regression with minimal adverse events. 4
- The FDA has authorized the first therapeutic cancer vaccine, marking progress in this field. 4
- These vaccines show signs of efficacy and potential to help patients resistant to other standard-of-care immunotherapies, but have yet to realize their full potential. 5
Vaccine Types Under Development
- Predefined vaccines: Target shared tumor antigens or personalized neoantigens specific to individual tumors. 5
- Anonymous vaccines: Include ex vivo cellular vaccines or in situ vaccination approaches. 5
- Vector-based, protein/peptide-based, and cellular-based delivery modalities are all under investigation. 6
Key Challenges
- Tumor-induced immune suppression significantly limits therapeutic vaccine effectiveness. 4
- Advanced cancer compromises the immune system, making vaccination less effective than in prevention settings. 7
- Aggressive treatments like chemotherapy further impair immune responses to therapeutic vaccines. 7
Vaccination in Cancer Patients (Infection Prevention)
Critical Importance
- Infections are the second most common cause of non-cancer-related mortality within the first year after cancer diagnosis, with most deaths from influenza and pneumonia—deaths preventable through immunization. 8
- Vaccination reduces infection severity and associated hospitalizations despite lower immune responses in cancer patients. 8
Core Vaccination Recommendations
- All cancer patients should receive: influenza, COVID-19, pneumococcal, recombinant zoster (RZV), tetanus/diphtheria/pertussis (Tdap), and risk-based HPV and meningococcal vaccines. 3
- Annual inactivated influenza vaccine is mandatory; live attenuated vaccines are contraindicated. 3
- PCV20 pneumococcal vaccine for newly diagnosed, vaccine-naïve patients. 3
- RZV for patients ≥50 years or ≥18 years at increased herpes zoster risk, given as 2 doses 2-6 months apart. 3
Optimal Timing Strategy
- Vaccines should be administered at least 2 weeks before starting cancer treatment whenever possible, as this provides the best protection. 8, 3
- If pre-treatment vaccination is impossible, administer early in the treatment process. 3
- Vaccination between chemotherapy cycles yields higher response rates than during administration. 8
- Avoid vaccination on the same day as cytotoxic therapy. 8
Critical Contraindications
- Live vaccines are absolutely contraindicated during treatment and for 3-6 months after cessation of chemotherapy or 6-12 months after immunosuppressive therapy (CAR-T, B-cell depleting agents). 8
- Patients may require revaccination at least 3 months after therapy discontinuation once immune competence is restored. 8
Post-Transplant Vaccination
- After hematopoietic stem cell transplantation (HSCT), influenza vaccination response is optimal if given >6 months post-transplant. 3
- CAR-T therapy recipients require similar revaccination schedules as allogeneic transplant patients. 8
Household Contact Protection
- Vaccination of household contacts and caregivers is essential to protect immunocompromised cancer patients through herd immunity. 8
- Most live vaccines (measles, mumps, rubella) can be safely given to household contacts. 8
- ACAM-2000 smallpox vaccine should NOT be given to household contacts due to transmission risk. 8
Implementation Strategies
Documentation and Workflow
- Document vaccination status at the first patient visit to identify gaps. 8
- Implement electronic reminders and standing orders to prompt vaccination during clinic visits. 8
- Nurse-led protocols have increased influenza vaccinations by 97% and pneumococcal vaccinations by 684%. 8