in cases where a patient has exhausted all treatment options, they can choose to enroll in a clinical study of an unapproved medicine. there are generally dozens if not hundreds of clinical studies for a given cancer type. if a patient is eligible for trials, these days they have plenty of options (however many pts are not eligible for studies). crispr based treatments would be one of many options

the 5 cancer studies of crispr treatments cited in the paper are all chinese studies, and all of them are basically crispr versions of therapies that work. for example, three of them use crispr to remove a gene that makes a protein called pd1. there are approved drugs that treat cancer by blocking PD1, and the safety of these is much better understood than crispr therapies.

for the patients in the crispr studies in china, there are drugs that essentially target the same disease related protein that are known to be fairly safe. so the patients could get a drug that probably works roughly as well as the crispr treatments but with less unknowns about safety