Pre-excisional Fixation of Tissues in the of Cancer in Rats* Treatment

A chemosurgical method for the removal of accessible neoplasms under complete microscopic control has been developed for use in human cancer. This is to be described elsewhere in the near future (2). The object of the present paper is to describe some of the animal research which led to the development of this method and which has been withheld from publication until the treatment had been applied clinically. The basic idea was to devise a method by which cancers could be removed in successive layers, each of which could be studied systematically under the microscope to determine the presence or absence of malignant tissue. Such a technic would have the obvious advantage of enabling the removal of a given cancer with a minimal destruction of normal tissue. The only practical and safe means of removing cancer tissues in layers required their chemical fixation in situ prior to excision. After such fixation incisions were made only through killed and fixed tissue thus avoiding all danger of spreading cancer cells over the cut surface. Moreover, the fixed, form-retaining specimens could be used for immediate frozen sections so that by systematic mapping of the area under suspicion in relation to anatomical landmarks, the exact location of residual areas of cancer could be determined. Further fixation was confined to the cancerous areas and the process was repeated until completely cancer-free tissue was reached. Fixative preparations and method o[ testing.--The first necessary step was the selection of a satisfactory chemical fixative along with a suitable means for its administration. For purposes of testing, rats bearing transplanted Philadelphia I sarcoma, mammary sarcoma MS-2, Flexner-Jobling carcinoma, and carcinoma C-256 were used. Preliminary experiments showed that application of fixative solutions alone to the tumor surface resulted in insufficient penetration while intratumoral injection not only gave erratic penetration but was often fatal because of direct entrance of the