Have you heard the saying necessity is the mother of invention? It applies to a lot of successful business stories — think oven mitts, the water bottle or the Shazam app.

It's also true for Emily McDowell. At 24 she was diagnosed with Stage 3 Hodgkin's lymphoma. The first among her friends to face a serious illness, she found that no one knew what to say.

Some people dropped out of her world completely, while some said absolutely the wrong thing without realizing it. And while the diagnosis rocked her world, she was totally caught off guard by the loneliness.

Fifteen years later and cancer free, McDowell, has launched a line of what she calls empathy cards. A new twist on an old idea.

There are eight of them in the set, half of them are cancer specific while the others are aimed at people with grave illnesses or who have suffered a sudden loss.

McDowell says they are cards that she wishes she had received when she was sick. She found that get well cards didn't really make sense because there was a chance she might not get well and the sympathy cards she received made her feel like she was already dead.

McDowell's goal with the empathy cards is for the people who receive them, she wants them to feel like they are heard and seen and understood. She also wants the people who are giving the cards to foster a real connection with the person who is sick.

McDowell says the reaction has been overwhelming. Her cards have been shared millions of times on social media. She's heard from everybody from patients to survivors to caregivers and their friends, from doctors and nurses, people with other grave conditions asking her to develop more.

Asked if she has a favourite, she says the one that has personal resonance says, "Please let me be the first one to punch the next person who tells you everything happens for a reason, I'm sorry you're going through this."

Clear, direct and a little bit funny. Much like the woman herself.