If you treat your lines with copper sulfate right after after having the line cabled it will provide you with some relief. You will just be killing the root ends and the roots may well continue growing. But it should allow time to budget for a line repair or replacement. Follow the manufacturers instructions.
Often removing the offending tree is an option but the roots may continue to grow for up to 4 years after the tree is removed unless you "kill" the stump.
If you only have the line cabled once a year you may decide to just figure that as an annual maintenance expense for awhile. One old codger in my home town did that for nearly 15 years before he decided to repair the line. He just didn't want the mess in the yard and felt it was worth having the line cabled once a year to avaoid it.
Work hard, Play hard, Sleep easy.