Many cancer patients and their families are happy to never look back once they’re safely on the other side of treatment, in remission or cured. But for David Austin and his wife, Emily, whose 6-year-old son now has a clean bill of health, winning the cancer battle was just the first step on another journey to help other cancer patients, particularly those whose treatment involves central lines — catheters placed directly into a vein in the chest to administer chemotherapy or take blood for frequent tests.