So what is the right thing to say? And more to the point, what are the wrong things to say?
"People constantly say to cancer patients: 'You look fantastic. You look so great,'" says Nancy Payeur, a team leader for patient and family counselling services at the BC Cancer Agency in Victoria. "And the cancer patients have mixed feelings about that because it's almost like they're saying, 'Are you really sick? You look just fine.'"
Some people with cancer have also been taken aback by such comments as: "'Oh, you've lost so much weight. How fantastic!'" she relates. "I mean, really, how ridiculous."
Payeur advises maintaining as much normalcy as possible to the person with cancer, but not saying in that hushed tone: "'Ohhhh, how are you doing?' Because I hear from people how annoying that is."
"They just want a normal conversation. They don't necessarily want to talk about their cancer. So I think something like: 'How are you doing?' and 'I've been thinking about you, and I know this is a difficult situation' — some acknowledgment, but not in a patronizing, over-the-top way."
Brittany Boniface used Facebook to keep family and close friends up to date with her fiance Steve Shaw's battle with testicular cancer prior to Christmas last year.
"It was definitely a shock for people when they saw him or pictures of him. He looked like a completely different person," she says, explaining that chemo had robbed the 26-year-old of his thick head of hair, eyebrows and eyelashes, and left him extremely pale.
"I know it's hard for people. They don't know what to say. Sometimes it's a very shocking thing to hear that someone has cancer, especially someone so young."
But as his 24-7 caregiver, Boniface got tired of hearing: "'I know how you feel.' It's like, 'Really? No you don't.' Unless you've been in those shoes, you don't know how that person feels."
When the Hamilton couple would tell someone about Shaw's diagnosis, "they would almost always tell us about a family member or friend that they lost from cancer, which was the worst possible thing to hear."
Instead, people should simply say they're sorry for what the person with cancer or their loved ones are going through and offer any help they can give, she suggests.
After Sara Schneiderman's mother went through chemotherapy and radiation for oral cancer last year, the already petite woman had shed "an enormous amount of weight" as well as her hair. The treatment also affected her ears, so she now wears hearing aids and walks with a cane.
"Of course, it is quite shocking when somebody hasn't seen you in a long time because they're not sure what to expect," says Schneiderman, whose mother is now in remission.
"And what we expressed to those who hadn't seen her was the truth. We said she had lost weight, she lost her hair and she's wearing a wig now. And we would focus on the positive accomplishments that she has come through."
"I think what happens naturally is that many people, when they are given a little bit of a head's up beforehand, people will reflect the positive that they see as well. They'll talk about the fact that you're post-treatment and they ask questions like 'How are you feeling now?'"
"And just to feel comfortable to do that is important."