Tumor Production
The research protocol should contain early removal criteria that minimizes pain/distress to the animal as required by the IACUC. Animals should be observed daily (including weekend and holidays), and body weight should be accurately determined (in grams) at least once a week (or more often if rapid weight loss secondary to tumor development or therapeutic agent administration is anticipated). Weight loss should not exceed 20 % of an adult animals weight. Alternatively, growing animals should attain at least 80 % weight gain as compared to control animals.
Tumor size should be measured using a caliper for best accuracy. The measurements will be used to calculate tumor weight as follows. For a spherical mass, the diameter will be measured and calculated (4/3pr3). This will be equated to weight in grams assuming that 1cm3 = 1 gram. For other elongated masses (not spherical) the mass will be calculated as cylinders - average diameter and overall length (pr2 x L). Again, consider the volume in cm3 to equal the mass in grams. The total of the mass weight (as determined by its measurements) will be subtracted from the current body weight. The % of the body weight represented by the mass will then be calculated.
Tumor burden should not exceed 10% of the affected animal's weight (i.e. in a 25 gram mouse, a single subcutaneous mass should not exceed 1.6 cm in diameter, in a 250 gram rat, the mass should not exceed 3.6 cm in diameter). In the case of multiple masses, these should be individually measured as described above. The individual mass measurements should then be totaled and this number should be used to calculate the total tumor burden as described.
Depending on the anatomical location of the tumor, the mass might interfere with normal function of vital organs (breathing, etc) or impede the expression of normal activities/behaviors (locomotion, eating, drinking, grooming, etc). In other cases tumors might ulcerate and/or become infected or induce signs of systemic disease (hunched posture, piloerection, hypothermia, dehydration, etc).
If an animal fits any of the previously described criteria (weight loss, failure to attain weight as compared to control animals, mass exceeding the allowed measurements, inability to express normal behaviors/functions, ulcerated/infected mass, systemic disease), a veterinary technologist should be informed by means of a properly completed ATR.
Once an animal is determined to fit the previous criteria, the principal investigator (PI) will be informed. Action should be taken within 24 hours of notification to avoid undue stress or pain to the affected animal. The measures to be considered will be in accordance to procedures specified in the approved research protocol and may include treatment or euthanasia.
Depending on the nature of the mass, some animals may become distressed. In this case, animals should be evaluated and measures taken regardless of the tumor size. These measures may include treatment or euthanasia.
