Last night during an interview with David Letterman, actor Michael Douglas surprised everyone with the news that he has stage 4 throat cancer.

It is amazing that the doctors are not using the word "throat cancer", for they believe that a lot of diverse range of cancers can affect various parts of the throat and mouth.

Douglas revealed that he has a walnut-sized tumour at the bottom of his tongue. If that's where his cancer has really begun, then there’s a likelihood that he is suffering from oropharyngeal cancer.

Physicians deem that base-of-tongue tumors are "insidious" in nature because the tumors can spread to a great extent without the person coming to know about it, as there is no pain associated with this type of cancer. And, it is already too late when the signs of cancer show up.

Oropharyngeal cancer might affect bottom of the tongue, the tonsils and nearby tissues, the soft palate, or the front and rear walls of the throat. It can be caused due to excessive smoking and drinking.

Har-El tells WebMD, "Smoking is a major cause of oropharyngeal cancer. Drinking alcohol, as far as the statistics can tells us, is not as bad by itself. But the combination of drinking and smoking is the worst combination".

Douglas is hopeful that he will recuperate from this illness.