Same as @scottbeammeup . My mom was in her early 80s at the time, and I called her right after I called my spouse. My spouse called my kids, and my mom called my siblings. Then my older daughter called friends and neighbours to organise a meal train for my spouse, so there would lots of food in the freezer for her to eat while she was spending much of her non-work time visiting me in hospital for the next few months.

We didn't even know what kind of cancer it was yet, but there was no doubt I was going to need a lot of support to get through whatever happened next. And I got it (as did my spouse and other family members). I pay that forward now whenever I can.

Of course, I would always respect someone's decision to keep cancer private, but I wouldn't recommend it (if asked): cancer's a battle you don't have to fight alone.