UT Southwestern IACUC Policy                                                     IACUC  # 101

Approval Date:__7/5/06______                                                   1 of 1

Rodent Tumor Burden

Rationale:

The Animal Welfare Act states that each research facility shall establish and maintain programs of adequate veterinary care that include the use of appropriate methods to prevent, control, diagnose, and treat diseases and injuries.

Tumors can grow rapidly and can compromise the health and well being of the research rodents. Tumors can become large enough to interfere with the rodent’s locomotion, grooming, and ability to access food and water. In addition, these tumors can ulcerate and result in secondary bacterial infections. If the tumor is growing in the abdominal or chest cavity, it can compromise respiration, and food intake.

Policy:
 
The IACUC recognizes the difficulty in establishing specific limits on tumor burdens for rodents due to host and tumor characteristics, personnel experience and skill, and research methodology; however, some guidelines must be followed.  Pathogen free tumor lines must be used.

Applicability:

This policy applies to all rodents used in research.
 
Exceptions:

Deviations must be clearly described and justified in an IACUC approved animal use protocol. 

Instructions:

The committee requires that these guidelines be followed.

• Some tumors, depending on type and location, may interfere with the function of vital organs, such as the lungs or digestive tract. If rodents are seen to be in distress according to the IACUC policy Guidelines on Quantitative Assessment of Pain or Distress in Rodents, they must be euthanized regardless of the size of the tumor or the weight of the rodent.
• Tumor-bearing rodents must be inspected daily by the PI or their staff once tumors are evident.
• Rodents must be euthanized if tumor size reaches 10% of body weight.  This can be calculated by

(weight of rodent with tumor) – (weight of age and sex matched control)   X 100
                                 weight of rodent with tumor

• Mice must be euthanized when tumors reach two centimeters in diameter or if the tumor size reaches 10% of body weight.
• Rats must be euthanized if the tumor size exceeds four centimeters in diameter or if the tumor size reaches 10% of body weight.
• All rodents must be treated or euthanized if a tumor develops full thickness ulcerations (tumors that break through the skin) as determined by the ARC veterinary staff.
• In some studies, either the tumor itself or anti-tumor therapies may cause the rodent to show signs of illness. Adult rodents must be euthanized if the animals lose 20% of their original body weight,
• If growing animals attain a weight less than 80% of untreated animals (i.e. littermates or control animals), they must be euthanized.
• If tumors interfere with locomotion, so that the rodent is unable to eat or drink, it must be euthanized.  The IACUC recommends tumor cells or promoters be injected in such areas as subcutaneous sites on the back or flank where growth is not restricted unless otherwise described in an approved animal use protocol.  ARC veterinary staff should be notified that the PI will place food on the floor of the primary enclosure   Please refer to the IACUC policy Feeding Laboratory Rodents on the Floor of the Primary Enclosure for more information
• Note:  ARC veterinarians are always available for emergency consultation on whether or not rodents meet these criteria. 

Contact Information:

For any additional questions, please contact the IACUC Manager at 5-6420.