Comparison of prognostic models in patients with advanced Hodgkin disease. Promising results from integration of the best three systems.
Several prognostic systems have been elaborated for patients with Hodgkin disease (HD) over the last 12 years, but early identification of a reasonably large group of both low and high risk, advanced stage patients remains unsatisfactory. Seven well known models were applied to 516 patients with advanced HD, with 315 patients used for the study sample and 201 patients used for the test sample. Individual performances as well as joint performances were analyzed univariately and multivariately in relation to overall survival, recurrence free survival, and time to treatment failure by means of a proportional hazards model. None of the models identified a group containing > 10% of patients from the total population who had a failure risk of either < or = 10% or > or = 50%. The systems of the International Database on Hodgkin Disease, the Memorial Sloan-Kettering Cancer Center, and the International Prognostic Factor Project showed the best prognostic power; only these three, when analyzed together, predicted clinical outcome with a statistically significant fit to the clinical data. Integration of the three systems in a linear model dramatically improved their individual discriminatory capacity by identifying patients with 10% and 50% failure risks, respectively, in 23% and 24% of the study patient population and in 19% and 25% of the test population, respectively. As powerful and simple new prognostic factors are awaited that may improve our predictive ability, this integrated index is probably the best way to exploit the significance of those presently available. The program required for the calculations can be downloaded from the Internet at the web site http://www.unimo.it/gisl/default.htm.