This is strictly from my experience. If the landlord is making attempts to have your home treated, you can not legally break your lease. You may ask the landlord to work a deal with you on breaking the lease however I doubt they are going to be willing to negotiate. My advice would be to ask her if you could pay half of whatever the cancellation fee is and get out of your lease. Other than that, if she is making attempts to treat your home for pests, you can not legally (without penalty) break your lease. You can put your rent in escrow if they are not making adequate attempts to remedy the situation. Your best bet is to contact a lawyer and speak with them.