How did your pumpkin turn out special ?
If you cut it back, it should allow the vine to focus more on the current pumpkin and allow it to grow larger, but you may not get new pumpkins. I wish I knew more, but I have either deliberatly or by accident cut back squash vines and my experience wasn't very good. They stopped growing beyond that point. It could be I cut them back too early and they hadn't branched out. It may be wise to do a search on pruning back pumkin and squash vines.
Personally I think it would be better off setting up a sturdy trellis for the vine to climb than to try cutting it back. You can use twist ties to anchor parts of the stems to the support and train the vine to climb. This is all provided you have a long enough growing season. Here in MN, our pumpkins and squash just may be done. If you see frost in your forecast, you may want to find some cloth or a garbage sack and cover that pumpkin to protect it.
oh brother dont ask me, I was going to post something like it LOL about how I can take cuttings from biourganvillea and plant them MJ where are you ......