Ian McKellen, 73, says he was diagnosed with prostate cancer “six or seven years” ago, but isn’t undergoing treatment. McKellen, best known for his work in the “X-Men” and “Lord of the Rings” movies, will be seen starting Friday in “The Hobbit: An Unexpected Journey.” “I’ve had prostate cancer for six or seven years,” he told The Daily Mirror. “When you have got it, you monitor it and you have to be careful it doesn’t spread. But if it is contained in the prostate, it’s no big deal. Many, many men die from it but it’s one of the cancers that is totally treatable so I have ‘waitful watching.’ I am examined regularly and it’s just contained, it’s not spreading. I’ve not had any treatment,” he said. “You do gulp when you hear the news. It’s like when you go for an HIV test, you go, ‘Arghhh, is this the end of the road?’ They come and say you have cancer of the prostate and then they say you can have it zapped, you can have it snipped, but you are not a candidate for that.”