"Cancelled without Prejuidice" means that they have cancelled the visa as it is no longer needed as they have approved you for your Permanent Residence. It also means that if you do not keep your Permanent Residence. you will have no difficulties in ever getting another visa should you ever need one
if a visa is cancelled WITH prejudice - then you would have had great difficulty in ever getting another US Visa
Source
if a visa is cancelled WITH prejudice - then you would have had great difficulty in ever getting another US Visa
Source
