Symbolism, Imagery, Allegory
Things seem like they'd be bad enough in Age of Iron even without throwing a terminal disease into the mix, wouldn't you say? So what's up with the fact that Mrs. Curren has to be dying from cancer while everything around her goes so terribly wrong, too? Lucky for us, Mrs. Curren gives us a couple of clues that link what's happening in the outside world to the disease that's running rampant inside her body. Let's take a look at things from her perspective as she tells John about her disease:
You know I am sick. Do you know what is wrong with me? I have cancer. I have cancer from the accumulation of shame I have endured in my life. That is how cancer comes about: from self-loathing the body turns malignant and begins to eat away at itself. (3.473)
Where does this cancer-causing shame come from? Probably from being a white person who's privileged at the expense of others because she lives in a society that oppresses non-whites. (And, by the way, for all you future doctors out there, we know shame doesn't actually cause cancer – it's a metaphor.)
So, what do cancer and Apartheid have in common? Well, let's simplify Apartheid and just call it hate. OK, so now, what do cancer and hate have in common? Well, for one thing, when either cancer or hate gets out of control, the results can be deadly. When cancer grows out of control, it kills a person from inside. And when hate grows out of control, as we see all too clearly, people kill one another and numerous others suffer. (You could also look at the country of South Africa as being riddled with the disease of hate, which is killing it from the inside.) It seems, then, that when Coetzee chose to create a character that's dying of cancer, he didn't do so to increase the amount of suffering we see in the novel. Instead, we'd like to argue that he gave Mrs. Curren cancer in order to create a localized and highly personal storyline that would resonate well alongside a really huge and hard-to-tackle subject like Apartheid.