Bronchial carcinoma. V. A methodological evaluation of the vitagram index for measurements of quality of survival by means of the "MaxMin" correlation method.

The validity of the Carlens Vitagram Index for measuring the quality of survival in bronchial carcinoma was further tested on the basis of the result of therapy in 48 patients with advanced disease, 54 patients with localized disease and 34 deceased patients surgically. Different approaches for index construction are discussed and the "MaxMin" correlation method, in which the highest of the lowest correlations is sought, is presented. The principal algorithms of the method are given, and the mathematical proof and the procedures are described and exemplified. By finding the "MaxMin" correlation a new index was constructed with weights of 20, 12.36, 12.36, 8.18, -6.15 and 0 points. The corresponding weights of the Carlens index are 20, 16, 12, 8, -4 and -2 points. Thus the Carlens index lies very close to the optimal index found with the "MaxMin" method. This result gives further proof that the Carlens index is valid for use in the types of bronchial carcinoma described above.