Cancer, as we all know, is a killer, and the struggle a patient goes through is a difficult one to understand unless you've been through the same thing yourself.
But the pressure to come up with something profound or inspiring when someone tells you of their diagnosis can make us say silly things, only serve to irritate or hurt them.
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The Breast Cancer Foundation understands that internal struggle, and has offered some advice on how patients and their family and friends can communicate better with each other.
Speaking on The AM Show on Monday morning, cancer survivor Hannah Dhanaraj explained just how difficult it is for people to say the right thing in the right moment.
"A cancer diagnosis can be very shocking, not only for the patient but also those who hear it. People want to help but they don't know what to say," she said.
"I was told 'you shouldn't carry anger, because that's what caused your cancer'. One shocking one was 'how awful for your husband to carry this burden'.
"Often though, the comments are not wrong in themselves - it's just that the timing is wrong."
Ms Dhanaraj says the best approach isn't to minimise the struggle, which is tempting to do with comments like 'keep your chin up' and 'stay positive' - but to acknowledge and offer your support.
"I think what you could say is, 'It's going to be a difficult journey, but I'm here with you, and I'll walk this journey with you'. That's all I wanted to hear.
"Someone told me once, 'you don't have to be brave all the time, you can just be honest with me and I will not judge you for it'.
"My husband was rock-solid, he was good. He could listen to anything, good and bad. [I had] amazing daughters who helped out at home."
Breast cancer is a very personal battle that is difficult to share with others, Ms Dhanaraj said, and that can sometimes lead to periods of isolation - even with many people willing to help.
"It is lonely because the medication just puts you under such stress. It's really hard to share that with somebody else," she explained.
"Sometimes you don't want to burden them, so that's when the loneliness sets in. Sometimes the medication itself can make you spiral downwards."
Offering practical support is a key area family and friends of breast cancer patients can do better in, Ms Dhanaraj explained.
"I had a lot of friends who texted and said 'just let us know what we can do'. But we didn't know what times worked for them and so it was quite tricky," she said.
"[People need to be] more specific, and actually do as much as they can possibly do. That's what helped in my experience.
"For example a friend said 'come over when you're tired of all the hospital visits'. Another friend just brought us dinner every Thursday night."
Sunday was World Cancer Day, which prompted the release of the Breast Cancer Foundation's video.