Sammy Davis JR died with millions of dollars worth of debt, leaving his estate in a shambles, a new tell-all book has revealed.According to Deconstructing Sammy, a forthcoming biography by Matt Birkbeck, the Rat Pack star was so broke in his final years that when he was diagnosed with throat cancer in 1989, he opted out of surgery which offered him an 80 per cent chance of survival.Instead, he chose to undergo radiation treatment, which only offered a 30 per cent survival rate, reasoning that if he couldn't sing, he couldn't make money.Davis Jr. died in 1990 owing $15 million (£7.5 million) to America's Internal Revenue Service (IRS) - despite earning more than $50 million (£25 million) in his lifetime, reports New York gossip column Page Six.