  We analyze the CCFR collaboration iron target data on the xF3 structure
function making particular emphasis on the extraction of the higher twist
contributions from data. Corrections for nuclear effects are applied in order
to extract data on the structure function of the isoscalar nucleon. Our
analysis confirms the observation made earlier, that the higher twist terms
depend strongly on the level to which QCD perturbation theory analysis is
applied. We discuss the impact of nuclear effects on the higher twist term as
well as on the QCD scale parameter Lambda_{\bar{MS}} extracted from the fit to
data.
