... and explore diversity among studies. Threats to validity include heterogeneity, citation bias, publication bias, language bias, and variations in study quality. Because meta-analysis defines rational treatment expectations at a population level, it is an adjunct to, not a substitute for, clinical judgment...

...) and [ 18 F]FDG uptake. Conclusions: Our results confirm previous clinical and histologic observations that squamous-cell carcinomas of the upper digestive tract are heterogeneous tumors. Ki67 antigen, which has been shown to be of predictive value for proliferation and individual prognosis, correlated...