Effect of surgical removal of subcutaneous tumors on survival of rats.

Mammary and other subcutaneous tumors were surgically removed from aged Sprague-Dawley rats in an attempt to extend survival. The surgical technique was straightforward, and survival following mastectomy was good (17/21). The number of mammary and pituitary tumors in sexually intact rats and those that had previously undergone ovariectomy were compared. The frequency of mammary tumors was significantly lower in ovariectomized vs sexually intact rats (2/47 vs 24/49), as was the frequency of pituitary adenomas (2/46 vs 27/41). Survival to 630 days of age was higher in ovariectomized than in sexually intact rats (42/47 vs 29/49), although tumors did not contribute significantly to mortality.