The Questionable Practice of Clinical Staging

THE QUESTIONABLE PRACTICE OF CLINICAL STAGING CHANDLER SMITH, M.D* Cancer therapy is evaluated by comparing the rates of survival after different methods of treatment. Valid comparison, however, requires that the two groups of patients be uniform with respect to tumor spread so that a difference in results may be attributed to the quality of the respective methods. Clinical staging is the practice used to equate the patient groups for this purpose. Several different staging systems are extant, revisions of them are periodically made, and the practice is in worldwide use. Nevertheless, the practice has a questionable aspect because the error of staging has a greater effect on the rate of survival than does the difference in the accomplishment of the methods. It is therefore not possible to determine whether a high result is due to a superior accomplishment of the method or a favorable staging of the disease. In view of this, the practice of clinical staging is deserving of critical examination . The Effect of Staging Staging affects the interpretation of results. For example, both conservative and radical methods succeed when all of the tumor is located within the tissue ablated by the conservative method, and both fail when some of the tumor is located outside of the tissue ablated by the radical method. Suppose two surgeons each collect 100 patients all of whom are judged clinically to be stage 1. In actuality, however, the first series consists of 95 patients curable by both methods and five patients curable by neither method. The second series consists of 90 of the former and 10 of the latter. The first series is treated conservatively, and the survival rate is 95 percent. The second series is treated radically, and the survival rate is 90 percent. The two surgeons presume their staging is accurate and conclude that the conservative method is superior. However, both methods achieve the same result for both series. Therefore survival rates are misleading, and a high result can never be attributed solely to the quality of the method of treatment. *Professor of pathology, Kansas City General Hospital and Medical Center, 24th and Cherry Street, Kansas City, Missouri 64108. Perspectives in Biology and Medicine · Winter 1976 | 273 The Error of Staging The error of staging has been especially well documented for cancers of the breast and uterine cervix. For example, 49 percent of 253 patients with cancer of the breast and clinically normal axillae were subsequently found to have metastatic axillary node disease [I]. In another tabulation, 27 percent of 420 patients were found to have clinically undetectable axillary metastases [2]. In addition, it has been observed that different examiners assign different stages of the disease to the same patient, and "positive axillae" were found in one-third of patients who did not have breast cancer [3]. It is for such reasons that an editorial in a prominent medical journal refers to the "fallacy of clinical staging" [4]. For cancer of the uterine cervix, van Nagell and associates found the error of staging to vary from 25 to 34 percent [5]. Others report inaccuracies of the same magnitude [6, 7]. Moreover, the tendency is to understage rather than overstage, and even microinvasive cancers are occasionally found to have spread to parametrial or more distant lymph nodes [8-10]. For internal cancers such as those of the stomach, pancreas, colon, kidney, and ovary, "clinical" staging is not possible, and in these instances tumor spread is estimated by surgical exploration of the primary site. Since the main purpose of staging is to evaluate the quality of the method, however, and since surgical disclosure of the extent of the spread affects the selection of the method, it is evident that the usefulness of this practice is lessened for these cancers. Clinical staging is therefore inaccurate for accessible cancers, and of limited use for inaccessible ones. The Effects of the Methods The difference in the accomplishment ofthe methods has only a slight effect on the rate of survival. For example, a radical method is superior to a conservative method only when the tumor has spread beyond the tissue ablated by the latter but not beyond the tissue ablated by the former as shown in...