Final answer:
Applying a TENS unit to the painful area has the effect of blocking pain signals to the brain.
Step-by-step explanation:
Applying a TENS unit to the painful area has the effect of blocking pain signals to the brain. TENS works by delivering low-voltage electrical impulses through electrodes placed on the skin. These electrical impulses help to disrupt the pain signals that are being sent to the brain, providing relief from bone cancer pain.