Feline Fibrosarcoma Recommendations

The CVMA Feline Fibrosarcoma Task Force developed the following recommendations:

  1. CVMA will develop a document as a sample form for written informed consent. This should be a statement that indicates veterinarians have informed the client of risks associated with vaccination.
  2. If a palpable vaccination inflammatory reaction persists for three months, the attending veterinarian should consider the option of surgical excision and submitting for pathologic evaluation.
  3. At present the manufacturer’s label recommendation is the only “official” item a veterinarian has to demonstrate the basis for vaccination. Annual revaccination, therefore, is actually based on a “minimum duration” of immunity and not definitive scientifically derived data.
  4. The USP Practitioners Reporting Form from AVMA must be used to report occurrences of vaccine-induced sarcomas or other adverse reactions. Submission of this form can be facilitated by diagnostic laboratories if they include a sample report with each diagnosis of vaccine-associated sarcoma or other adverse effects. The record is to include vaccine type, lot number and vaccination site. This information can also be incorporated into the patient’s file. Adverse events associated with feline vaccination should also be reported to the manufacturer of the product and the USDA.
  5. Vaccination sites shall be left side for FeLV, right side for rabies. These vaccines are to be administered in the distal limb (below the elbow or stifle) in the event that neoplastic transformation takes place and amputation of the limb becomes necessary.
  6. Alternate vaccination routes, e.g. nasal, topical, should be considered when available.
  7. Use the term “vaccine-associated sarcoma” in CVMA’s future communications to veterinarians.
  8. Survival rates in cats with vaccine-associated sarcomas are low. Most institutions offer surgery alone or surgery coupled with radiation and/or chemotherapy. Although there is no definitive treatment that has proven successful, it was agreed clients should be advised to consult an oncologist for available alternative therapies that might be available.
  9. CVMA encourages the use of single dose vaccine vials as opposed to multiple dose vials to assist efforts to standardize quality and variation of adjuvant the patient receives, especially for products employing aluminum-based adjuvants. Vaccine vials used in veterinary medicine should include peel-off labels to assist record keeping and follow up studies.
  10. Veterinarians should emphasize to clients the value of annual examination of adult cats in addition to vaccine and/or laboratory testing schedules.
  11. CVMA will publish information emphasizing the importance of reporting tumors and the veterinarian’s obligation to assist the reporting process, as well as to inform clients of the demonstrated risks associated with vaccination.

Based on recent veterinary literature the prevalence (and apparent incidence) of vaccine reactions in general, and vaccine-associated sarcomas specifically, have increased in recent years in the feline population. When we consider vaccination we must be mindful that this procedure is not an innocuous one, and that the owners of animals need to be apprised of the potential for adverse reaction. The benefit and basic need for vaccination must then be balanced against these adverse reactions.

The task force members were selected from a broad perspective of veterinary medicine, all with special interest in feline fibrosarcoma.

© 2021 California Veterinary Medical Association

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