The color dipole model is traditionally applied to forward rapidities. Alternatively, we employ the dipole model to obtain backward rapidity distributions. We have chosen to work with dilepton production in pAu and pp collisions at RHIC and LHC energies. The results are best understood with the help of a nuclear modification factor RpA as a function of transverse momentum and of rapidity. As it is found, dilepton production at backward rapidities is very dependent on nuclear effects.