Policy Number: 2007-032-v
Policy Title: Tumor Burden in Rodents

POLICY: Animals that have experimental or spontaneous tumors must be euthanized before the tumor affects the animal’s well-being. Euthanasia of animals with tumors is indicated if:

  • tumor burden causes an impediment to normal movement or normal body functions of the animal.
  • tumor burden causes a loss of body condition, resulting in a body condition score of less than 2, using the scoring method found at the following paper: Lab Anim Sci. 1999 Jun;49(3):319-23 (Body condition scoring: a rapid and accurate method for assessing health status in mice). For some tumors, weight loss is an acceptable substitute for body condition scoring; a maximum of 15% weight loss is permitted.
  • there is skin necrosis over the tumor.
  • animals exhibit extreme lethargy, such that they are unresponsive to a mild stimulus.
  • clinical signs indicate the primary tumor(s) has metastasized, e.g., seizures, labored breathing.
  • the tumor or its sequelae are causing pain as evidenced by chewing or excessive grooming of the tumor and/or surrounding area.

The investigator must include in the animal protocol a written description of clear endpoints that fall within the above guidelines and adhere to the approved endpoints. If exceptions to the guidelines are requested, a clear, scientifically justifiable rationale must be described. In addition, any measures that will be taken to ensure the animals’ comfort and well-being must be clearly described in the protocol and subsequently provided to the animals. All monitoring and treatments must be documented.

The veterinary clinical staff will investigate any observed tumor to determine if they meet the approved endpoint criteria. If so, the investigator will be contacted so that euthanasia can be performed as soon as reasonably possible. If the investigator is not available or does not respond, the veterinary staff will arrange for timely euthanasia.

The ACUC shall review proposed protocols for conformity to these guidelines and enforce compliance.

Author: J. Welter
ePublication Date: 3/2/2007; Reviewed, no changes 9/2017