I misread the original question — yes, “the word” and “cancer” are in apposition to each other. What they are embedded in an absolute phrase, just in case you needed to know that.

When a participle and the noun that comes before it

combine to form an independent phrase definition, the structure is called an absolute phrase.

They ran down the hill but

  still hid in the background. Wherever they were, these children are described. *The party having finally gone,* we started cleaning up the debris.  

So in this case,

  the word Cancer exploding in the living room like a time bomb detonated by his grief has  

the same format. It follows the pattern for a phrase absolute.

I misread the original question — yes, “the word” and “cancer” are in apposition to each other. What they are embedded in an absolute phrase, just in case you needed to know that.

When a participle and the noun that comes before it

combine to form an independent phrase definition, the structure is called an absolute phrase.

They ran down the hill but

  still hid in the background. Wherever they were, these children are described. *The party having finally gone,* we started cleaning up the debris.  

So in this case,

  the word Cancer exploding in the living room like a time bomb detonated by his grief has  

the same format. It follows the pattern for a phrase absolute.