Further Quantitative Methods for the Study of Transplantable Tumors. the Growth of R39 Sarcoma and Brown-pearce Carcinoma

The various methods that are used for the study of tumor growth can be classifiedinto three groups-the pictorial, the statistical, and the graphic. In the pictorial method, silhouettes are employed to represent the growth of the tumor. In the statistical method, the ultimate size of the tumor, the number and size of metastases, and other criteria of growth and malignancy are analyzed statistically. In the graphic method, tumor growth is represented by curves plotted with time as abscissae and some measure of tumor size as ordinates. Of these three methods, the graphic permits the most detailed study of the growth of each individual tumor. One graphic method for the study of tumor growth was presented by Mottram and Russ (1). These investigators represented the growth of an immunizing tumor, Jensen rat sarcoma, with time as abscissae and the logarithm of volumes as ordinates. They obtained four types of growth curves for this tumor: the progressive, the retarded, the oscillating, and the disappearing. These four types were associated with different degrees of immunity to tumor growth. Disappearing tumors occurred in rats with the highest degree of immunity and progressive tumors occurred in rats with little or no immunity. Another graphic method using the mean diameters instead of logarithm of volume as ordinates was presented in a previous paper (2). This method permits the representation of the growth of the Walker tumor and the FlexnerJobling carcinoma by linear growth curves. As these two tumor strains produce little or no immunity in the rats of this laboratory" further work was needed to extend this graphic method to tumors which produce a high degree of concomitant immunity. The R39 rat sarcoma and the Brown-Pearce rabbit carcinoma were chosen for this purpose.