Some big cities could see shortages of cancer specialists in the coming decade, according to a new analysis by Doximity, a social network for more than a million physicians. Researchers at the company delved into the data on oncologists and found there’s an imminent wave of retiring physicians. The areas most likely to see shortages: Miami, Virginia Beach, and Tampa. But other cities could also see large portions of the cancer physician workforce retire relatively soon. In half of the 50 metropolitan areas surveyed, more than 20 percent of practicing oncologists are over age 65.