Tumor Policy for Mice and Rats (IACUC)

After a tumor or cell line has been injected, animals must be observed 3X/week and weighed or body condition score assessed at least 2X/week and findings documented. Once signs of morbidity have been identified or a tumor has reached 50% of the maximum allowable size or 10 mm in any dimension in mice and 20 mm in any dimension in rats, the animal must be observed daily, including weekends and holidays, and findings documented.

The site of tumor implantation should be chosen to minimize damage to adjacent normal structures. Sites involving the special senses should be avoided. Clearly defined endpoints must be stated in the IACUC protocol if different from those stated in this policy.

The visible size of the tumor is only one of the criteria used for determination of humane endpoint. The overriding consideration for humane endpoints of oncological experiments as well as spontaneous tumors must be the overall health of the animal. For subcutaneous tumors the maximum allowable size is 20 mm in diameter for a mouse or 40 mm diameter for a rat. If the animal is host to more than one tumor, this size is the maximum allowable size for all tumors combined.

For cutaneous or subcutaneous tumors, ulceration is a standard humane endpoint criterion. If a particular tumor model is expected to exhibit ulceration or experimental endpoint needs to extend past the point of ulceration, those presentations and endpoints should be described in the IACUC protocol.

All tumor-bearing animals must be observed on a scheduled basis and findings documented to assess the progress of tumor growth and/or metastasis, and the general condition of the animal. Records must be kept and be available in the animal room with all pertinent information including time and frequency of monitoring sessions, the name of the person monitoring the animals, identification of the animals, protocol number, the number of animals displaying clinical signs, types of clinical signs, and any treatments given to the animals.

Debilitating clinical signs observed after tumor growth and grounds for euthanasia:

• Impaired mobility (the inability to reach food and water)
• Inability to remain upright
• Interference with a vital physiological function, such as breathing, chewing, swallowing, urination, defecation, or locomotion
• Location of the tumor on the animal’s belly or its inner leg causing the tumor to be abraded or to interfere with locomotion
• Hunched abnormal posture
• Labored breathing and cyanosis [bluish pinnae (ears), feet, or mucous membranes]
• Clinical dehydration and/or prolonged eating or drinking
• Muscle atrophy and signs of lethargy and lack of physical activity
• Weight loss/Body condition score less than 2
• Chronic diarrhea or constipation
• Hematological or biochemical values that indicate organ failure
• Severe anemia [pale pinnae (ears), feet, or mucous membranes]
• Bloodstained or mucopurulent discharge from any orifice
• Self-mutilation; lack of grooming behavior; rough/unkempt hair coat
• Enlarged lymph nodes or spleen
• Significant abdominal distension
• Cranial deformity/neurological signs
• Exophthalmos (bulging eye)
• Skin pathology including ulceration or necrosis over the tumor
• Restlessness/inability to get comfortable
• Unconsciousness with no response to external stimuli

In circumstances involving declining health status, moribundity, or unrelieved pain and discomfort, every attempt will be made contact the PI in a timely fashion to reach consensus with the PI bearing experimental endpoints in mind. However, the final analysis and responsibility for animal welfare rests with the attending veterinarian.