F* cancer. On my mother's side, her mom and sister died of breast cancer, her other sister caught it early, her brother died of cancer (throat or lung, not sure). She removed her breast 20 years ago at almost 50, went through chemo and radiotherapy, she was a survivor, cured. Just a month ago got headaches and turns out new brain tumor. Neurosurgeons removed it, but against all odds nothing to do with the old cancer, not a metastasis, but a new primary wildtype glial grade 4 tumor. It's just not fair.
If incidences of cancer of any type are 1 in 100,000 for the population at large, then generally any slice of that population will have similar odds. Which includes people with cancer.
So those who already have cancer, have a chance to develop a second cancer.
It is very not fair.
We all die eventually. All you can do is live your best life. Unfortunately we don't all get the same hand from the dealer.