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The American Joint Committee on Cancer proposes the following criteria for evaluating putative prognostic factors: they must be (1) significant, (2) independent, and (3) clinically important. Furthermore, we suggest the criteria for selecting a prognostic system that includes TNM and new prognostic factors. These criteria are: (1) easy for physicians to use; (2) provides predictions for all types of cancer; (3) provides the most accurate relapse and survival predictions at diagnosis and for every year lived for each patient; (4) provides group survival curves, where the grouping can be by any variable including outcome and therapy; (5) accommodates missing data and censored patients and is tolerant of noisy and biased data; (6) makes no a priori assumptions regarding the type of data, the distribution of the variables, or the relationships among the variables; (7) can test putative prognostic factors for significance, independence, and clinical importance; (8) accommodates treatment information in the evaluation of prognostic factors; (9) accommodates new putative prognostic factors without changing the model; (10) accommodates emerging diagnostic techniques; (11) provides information regarding the importance of each predictive variable; and (12) is automatic.

Examining costs and utilization in a single-payer universal health care system provides information on fiscal and resource burdens associated with head and neck cancer (HNC). Here, we examine trends in the Department of Defense (DoD) HNC population with respect to: (1) reimbursed annual costs and (2) patterns and predictors of health care utilization in military only, civilian only, and both systems of care (mixed model).

It is estimated that 20–40 of advanced medical imaging in the United States is unnecessary, resulting in patient overexposure to radiation and increasing the cost of care. Previous imaging utilization studies have focused on clinical appropriateness. An important contributor to excessive use of advanced imaging may be a physician “knowledge gap” regarding the safety and cost of the tests.

Lower serum albumin concentration (sAlb) and higher levels of pro-inflammatory cytokines have been reported to predict death in patients treated with haemodialysis (HD). SAlb, along with anthropometric measures, has been used as a surrogate marker for nutritional status in patients with chronic disease. Though adequate nutrition has been considered an important factor for patients treated with HD, it has not been established if any nutritional markers other than lower serum albumin and lower body mass index (BMI) predict death. Furthermore, it has not been shown whether anthropometric measures other than BMI are associated with predictors of mortality.

The human genome is a complex system characterized by gene interactions and nonlinear behaviors. Complex systems cannot be viewed as the aggregate of their isolated pieces but must be studied as an integrated whole. Microarray technologies offer the opportunity to see the entire biological system as it existed at one moment in time. It is tempting to try to analyze the entire microarray at once to immediately discover the pattern being sought, for example, the pattern of a breast cancer. However, such an analysis would be a mistake because microarrays provide massively parallel information, the analysis of which is a nondeterministic polynomial time (NP)-hard problem. Current statistical methods are not sufficiently powerful to solve this NP-hard problem. The best approach to microarray analysis is to begin with a small number of the elements in the microarray known to be a pattern and ask questions of the other elements in the microarray; i.e., perform instantaneous scientific experiments regarding whether each of the other elements in the microarray are related to the known pattern.

To the Editor.—There have been several studies comparing the academic performance of male and female first-year medical students.1-3 Generally, men perform better than women in the basic sciences. But none of these studies controlled for prior course work. It could be that men achieve higher test scores in the basic sciences in medical school because, prior to matriculation, they have taken more courses similar to those required in medical school than women have. To deal with unequal preparation, this study adjusted for prior course work by examining, by subject, the academic performance of those male and female medical students who did not have any prior course work in that subject.Study.—The numerical grades of the freshman medical students at the University of Chicago Pritzker School of Medicine in 1984 were obtained for the following courses: Anatomy I and II, Histology, Biochemistry I and II, Physiology I and

To the Editor.—The CASE REPORT by Roifman et al1 regarding the use of immune serum globulin in the treatment of chronic polymyositis requires clarification. The authors describe a patient with "normal immunity," but they did not provide any information regarding what this means. We need to know what immunologic studies were performed (eg, measurement of immunoglobulin, complement, and rheumatoid factor levels and antibody titers) and the results of those studies if we are going to understand what the authors mean by normal immunity. This knowledge is important because the intravenous infusion of γ-globulin has been associated with the death of a patient with abnormal immunoglobulins.2 If there is the slightest doubt regarding the patient's immunologic status, the prudent course is to begin with a test dose of immune globulin before proceeding to a therapeutic regimen. Finally, since spontaneous remission is possible in polymyositis, it is difficult to