Whether recency is of critical importance in your research will be decided primarily by your topic and your purpose. If your purpose is to discuss the latest cutting-edge treatments for cancer, then recency is a vital component for that speech. On the other hand, if your purpose is to review how cancer treatments have changed over the past decade, recency is not as crucial. Your intent in the latter speech would be to give a historical overview of cancer treatments, moving from earlier findings to more updated research. Obviously, your goal should be to find the most current data available to support your claims and ideas, but there are other criteria that you must consider as well.