If you don't treat the manholes outside your home they will keep coming. I have a pest control company spray the manholes outside my home twice a year. A good time to do it is when the weather starts getting hot; that's when they start to invade.
Last time we did it the main manhole was blocked. Hundreds, literally, hundreds of cockroaches came out. They were all over the ground, walls, pest control guys!
They died, eventually.