Finally, the court erred in granting in part the motions of Dr. Powalski and Dr. Martinez for summary judgment and dismissing the derivative cause of action, and we therefore further modify the order accordingly. The continuous treatment doctrine applies to toll the statute of limitations with respect to that cause of action to the same extent that it applies to the primary cause of action ( see Ewen-Massa v. Hemmerlein, 237 AD2d 968; Cappelluti v. Sckolnick, 207 AD2d 763, 764).