At age 43, English author and journalist Sarah Gabriel, was diagnosed with breast cancer. She had two young daughters and a loving partner and while cancer took her mother at a young age, she was determined not to accept her genetic legacy.

In her new memoir, Eating Pomegranates, Gabriel writes about her fight to survive, stay sane, to protect her young daughters and to stop the BRCA1, the rare and deadly genetic mutation that had caused her cancer, from claiming another victim. Gabriel also sketches a history of breast cancer treatment, from surgery without anaesthetic in the nineteenth century to modern chemical regimes

In a series of columns for That'sFit.ca, Gabriel, now three and a half years out from diagnosis, recounts her experience with this all too common disease. In this installment she explains the pressure your relationships go through as you battle the illness. To read previous columns, click the 'Breast Cancer' link at the top of the page.

This is a tough subject. And it's not really talked about enough. As you go through cancer, your relationships come under pressure – I mean all of them: with friends, family, partner and children. It's like a piece of flotsam caught in the path of an ocean liner bearing down. You don't know what's going to be left behind in the wake.

Some people are lucky. They come from families that know how to provide the maximum of warmth, understanding, support and care. Others are less lucky, as I describe in my book Eating Pomegranates. Cancer doesn't just happen to perfect families. It happens to normal ones - that is to say, averagely messed-up, only partly functional ones.

And under pressure, messed-up families may get more, not less, dysfunctional. They may run a mile. They may fall apart altogether. They may become cold and harsh. They may simply deny that the whole thing is happening. There are all sorts of ways of avoiding unwelcome truths.

I don't know any pain-free way of dealing with the fact that when you go through cancer some of your family and friends are likely to fail you, just as others will exceed all expectation in their immense generosity and loyalty. But perhaps one thing worth remembering is that, when other people can't cope with your cancer, IT'S NOT YOUR FAULT.

Cancer is big stuff. It goes to the heart of the human predicament. Send not to know for whom the bell tolls, as the English poet John Donne said, It tolls for thee. Fear is an unpredictable quality. And when people are afraid, you don't see the best side of them. They may exhibit a fight or flight response. They may get angry with you for getting ill; or angry with you for being sad about it, which puts them under uncomfortable pressure; they may wish you would just take your medicine and shut up, like a child with measles. They may become suddenly preoccupied - with children, travel, a new job – just when you need them most.

So you get the stories, on the bulletin boards of cancer websites, in the support groups, or talking at any length with someone who has had cancer.

"There is the woman who came down her front path after her diagnosis to see her 'best friend' pull her hooded anorak down over her face and cross to the other side of the street," as I write in Pomegranates. "The friendship never was repaired.... There is the man dying of lung cancer whose siblings don't come to see him even though they live just half an hour away... There is the woman who has to have a stem cell transplant for her aggressive cancer....Her prognosis is poor: a 10 per cent chance of surviving two years. She would like the consolation of making plans, of knowing how her children might be cared for. But her mother and sister consider it their duty to give her pep talks. 'Now Mary, you've got to stop this morbid thinking.... You've got to be positive, or you'll make yourself ill.'"

I sometimes found the effort of coping with other people's fear when I was going through treatment too much. It exhausted my vanishingly small reserves of energy. And I felt that if I heard a single other person telling me to 'be positive' as the cure for several Grade III breast tumours I would scream.

In this regard, I found attending a support group and private counselling sessions very helpful. There was a place I could go to where I was 'normal'. I was not expected to pretend that what was happening to me wasn't happening for fear of frightening anyone else. I learnt from these sessions that I was not alone. Other people too experienced alienation and difficulties with their surrounding social world when going through treatment, albeit with a different cast of characters, and a different set of details.

On the positive side of this, you will also be surprised (I hope you will) by the number of near strangers who step forward to help you in ways you couldn't have imagined. They may be able to do so because of their own life experience, the fact that someone once did the same for them, the accidents of their psychic make-up, or because of their professional training.

When you come through it, you may find that you have gained as much as you have lost. You may be broken-hearted because some relationships on which you counted couldn't survive in any close form. But on the other hand, others will have been tested in the fire. You will have forged something profoundly rich and enduring together because of troubles faced as one.