>>One can speculate: To good to be true?
Or there is something?>>
Most probably more good than true. One of the references given at Yahoo! (referenced by Nigel) was the following.
Survival and Prognostic Stratification of 670 Patients With Advanced Renal Cell Carcinoma
Robert J. Motzer, Madhu Mazumdar, Jennifer Bacik, William Berg, Alison Amsterdam, Joseph Ferrara
From the Genitourinary Oncology Service, Division of Solid Tumor Oncology, Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center; and Department of Medicine, Cornell University Medical College, New York, NY.
Address reprint requests to Robert J. Motzer, MD, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10021
PURPOSE: To identify prognostic factors and a model predictive for survival in patients with metastatic renal-cell carcinoma (RCC).
PATIENTS AND METHODS: The relationship between pretreatment clinical features and survival was studied in 670 patients with advanced RCC treated in 24 Memorial Sloan-Kettering Cancer Center clinical trials between 1975 and 1996. Clinical features were first examined univariately. A stepwise modeling approach based on Cox proportional hazards regression was then used to form a multivariate model. The predictive performance of the model was internally validated through a two-step nonparametric bootstrapping process.
RESULTS: The median survival time was 10 months (95% confidence interval [CI], 9 to 11 months). Fifty-seven of 670 patients remain alive, and the median follow-up time for survivors was 33 months. Pretreatment features associated with a shorter survival in the multivariate analysis were low Karnofsky performance status (<80%), high serum lactate dehydrogenase (> 1.5 times upper limit of normal), low hemoglobin (< lower limit of normal), high "corrected" serum calcium (> 10 mg/dL), and absence of prior nephrectomy. These were used as risk factors to categorize patients into three different groups. The median time to death in the 25% of patients with zero risk factors (favorable-risk) was 20 months. Fifty-three percent of the patients had one or two risk factors (intermediate-risk), and the median survival time in this group was 10 months. Patients with three or more risk factors (poor-risk), who comprised 22% of the patients, had a median survival time of 4 months.
CONCLUSIONS: Five prognostic factors for predicting survival were identified and used to categorize patients with metastatic RCC into three risk groups, for which the median survival times were separated by 6 months or more. These risk categories can be used in clinical trial design and interpretation and in patient management. The low long-term survival rate emphasizes the priority of clinical investigation to identify more effective therapy.
These results are in line with what Peter has already posted, i.e. that there may well be a fairly large degree of variability with regard to expected survival times depending on the patients status at the time of recruitment into the study.
On the other hand - the design of the study (50 % on placebo) should in my opinion ensure that the number of patients doing "relatively well" was not over-represented. Patients with 0 risk factors would most probably think they would have better chances in other studies.
Erik |
