Event forwarding in a content-based publish-subscribe system is an expensive task due to the need to match an event?s content against registered subscriptions at every router. We introduce lookup reuse, a novel approach to improve the efficiency of event forwarding. Lookup reuse enables faster event forwarding through reusing matching results computed by upstream routers in making forwarding decisions at downstream routers. In many cases, this lets downstream routers replace an expensive content-match with a much cheaper hash-table lookup. We investigate the integration of lookup reuse into existing content-based event forwarding algorithms. Our simulations show that lookup reuse reduces the event processing overhead on average by 40 to 55 percent, when used with existing content-based event forwarding algorithms.