Paul Raines, chief executive of Grapevine-based GameStop, will undergo chemotherapy after surgeons removed a small brain tumor last week, the company said Tuesday.In a statement filed with the Securities and Exchange Commission, the electronics retailer said the tumor was “very small” and “successfully removed from an easily accessible part of the brain.” Because it was found early, doctors have advised Raines that his prognosis for a full recovery is “very good,” the company said.Raines, 50, has been GameStop’s CEO since 2010, having joined the company from Home Depot as chief operating officer in 2008. Most recently, he has led the video game retailer into new areas of commerce by expanding two chains acquired last year: Spring Mobile, which sells AT&T wireless equipment, and Simply Mac, which sells Apple products.The preventive chemotherapy treatments are expected to take about six weeks, during which his travel will be restricted.“We have every confidence in Paul’s continued leadership and wish him a speedy recovery,” GameStop Executive Chairman Daniel DeMatteo said in a statement. “While he recovers, our highly-tenured executive team will ensure that our business continues without interruption.” The company, which operates about 6,600 stores worldwide, is expected to release its second-quarter earnings report Thursday. In the first quarter, GameStop reported net income of $68 million, up 25 percent, and sales growth of 7 percent as it benefited from strong demand for new Xbox One and PlayStation 4 gaming systems.GameStop shares (ticker: GME) closed up 23 cents at $40.88 on the New York Stock Exchange. The National Cancer Institute estimates that 23,000 new cases of brain and other nervous system cancers will be detected in the U.S. this year. An estimated 14,000 people will die from such cancers in 2014.Since brain tumors are diverse, response to treatment varies among patients, according to the Memorial Sloan Kettering Cancer Center. Surgery is the best treatment, and chemotherapy has been increasingly used in recent years after surgery and radiation. This report includes material from Bloomberg News.