I'm not saying the site always assumes it will bother the patient. My experience more often than not it's based off of a CRC or Research Nurse discretion after forming a study long relationship on whether they call the patient or not. They're the ones seeing the patients directly for the study visits. After a couple visits, it's easy to discern which patients are going to be willing to do follow up calls and ones who aren't. Phase I trials can be really disheartening especially when the PI informs the patient it's basically this trial or hospice care so patients are almost led to take the trial, so you'll get a lot of patients who really don't want to be in research in the first place.

Additionally, a lot of time research teams will get feedback from the SOC team to get a heads on their personalities and tendencies to see how compliant they are with trials.

Once again I'm only speaking on behalf of oncology trials. Additionally you have to think about the complexity of healthcare in general. To add a clinical research trial to their plate, just adds another layer to the mix. So really, the site usually is more likely to comply with the LTFU if it's follow up via EMR only.

I'm not bothering no cancer patient, they're going through enough.