We use a special foam to inhibit root growth in sewer mains, and, in the case of your own pipes, you can get a plumber to do the same or use an electric eel. Repair and reinforcement of the affected sewer pipes is also a practical option worth considering.
However, in severe cases you may need to consider removing the offending tree. If this is the case it is vital that you correctly identify which tree is causing the damage. You should then obtain a copy of your local council’s Tree Preservation Guidelines, as you will need their approval to remove the offending tree.